A version of this article was first published in the August 2011 issue of Drinks Business.

There are many reasons why producers select particular types of closures, and while quality is always high up the list in the mix of reasons, it’s not always the one that holds sway in the final reckoning.

More often than not a selection of closures is used across the range of wines made.  South Africa’s Cape Point Vineyards is a case in point. Their winemaker Duncan Savage said their “approachable range is bottled under screwcap, [which is] user-friendly and cost effective at the price point.”

The 2010 vintage of their premium Cape Point Sauvignon Blanc was bottled under screwcap for the first time, but, Savage said, we “will be returning to cork on the Cape Point Sauvignon Blanc. Our wines from the Cape Point area are generally quite tight and mineral when young and blossom better under cork than screw cap.” Altogether about 30% of Cape Point Vineyards’ wines are stoppered with cork-based products, and while “taint is always the risk” added Savage, “our wines are just better under cork, they might not be perfect and faultless, they just taste better.”

Sometimes choice of closure can be as mundane as what’s available in the country of packaging, or the neck type of bottle available at the point of bottling. Larry McKenna was bottling his Escarpment and Single Vineyard wines under diam. But a shipping strike meant he couldn’t get bottles from France which were “30% cheaper because of the lack of demand in NZ for cork mouthed glass”.  Combined with new commitments to pursue carbon neutrality, McKenna has “decided to go with screwcap for all Escarpment products. With this saving in costs it has allowed us to buy the local, expensive glass and to be able to afford the best corks we can buy for the Single Vineyard wines. We feel there is some marketing advantage for wines under very high quality corks at the ultra premium end.”

Market demands are important dictators of closure choice, as the reports illustrate citing the need for New Zealand producers to return to cork in order to successfully penetrate the Chinese market.  John Hancock, president and founder of Trinity Hill in Hawke’s Bay said “China, which has become our number two export market very quickly, will not take wine in screwcap, so we bottle specifically for them in Diam. They are happy with that.” This position is reflected by Weingut Baron Knyphausen in Germany’s Rheingau. Their general manager Wolfgang Frank said “we have negative feedback for screwcap from our first presence in China.”

In all though, Trinity Hill put about 20% of their products under cork-based stoppers, and have done for some time. Hancock said “our Hawkes Bay range (entry level) moved from cork to screwcap with the 2003 vintage [and] we changed from natural cork to Diam for our Gimblett Gravels range. Our very top end Homage has stayed predominantly with natural cork, even though we have done a portion in Diam as an on-going trial.”

Hancock added “We like the structure of where we are right now and have resisted the lemming like approach of NZ wineries putting everything in screwcap. As closures evolve, we will evaluate them and use the most appropriate closure for each wine style.  There is not a ‘one fits all’ answer.”

There are a few other souls in New Zealand not among the 98% of producers who top their bottles with screwcaps. James Millton, of Millton Vineyards said “In 2010 we committed all our ‘village’ and premier wines to screwcap. We tried Diam but still I could smell these closures. We changed because of the number of de-listings we were facing from restaurants and bars who would not have taken the wine if they knew prior that they were closed with cork.” But he continues with cork for his premium Clos Ste Anne, “which I will never change”, adding “many consumers said that we shouldn’t return if we didn’t have screwcaps.”

The new world/old world divide is strong on this aspect, as Frank expressed the opposite experience, saying “we are using screwcaps as well as cork stoppers for our wines. We are using cork due to acceptance problems of screwcap in the high price range.” Charta regulations impose no rules on choice of closure.

Such market pressure is difficult to resist. “Tapanappa has been bottled exclusively under very expensive and good cork up until 2010” said Brian Croser. But the newer, less expensive, earlier-consumed ‘wines of terroir’ regional wines have been stoppered with screwcap. It’s “mostly commercially driven, responding to what the Australian wine press, the retailers and indoctrinated consumers are demanding” he added.

For Chilean producer Concha y Toro, their head winemaker Marcelo Papa said “for a couple of years people from the UK market were pushing us to change reds from natural cork to screwcap. We decided to continue with natural cork … we export wine to many [other] countries and they push strongly for natural cork.”

In terms of decision making parameters, Papa said “First is the variety and the style of wine. If it’s sauvignon blanc, I have no doubt and I push screwcap. With pinot noir, I’m half and half: medium level pinot noir could work well with screwcap; for high quality I have cork. Then is the country we will mainly sell. And the cost is getting more important. Screwcap is less expensive than natural cork.” But he added “if the market doesn’t accept [a type of closure], I can’t sell.” And he has to sell.  Of his 3 million cases of Casillero del Diablo, which sells in 120 countries, about 75% is cork-stoppered.

Though South America hasn’t embraced the screwcap revolution to the same extent as the UK and Australasia, the market leaders continue to innovate in this direction. Adolfo Hurtado, managing director of Cono Sur, said “we use screwcaps in all our more competitive wines, all the varietal wines; we keep natural cork only for our premium red wines, because premium reds need a small proportion of oxygen to keep improving in bottle, but varietal wines are consumed in 6-8 months, so we much prefer to use screwcap.”

This means cork still accounts for 20 to 25% of total Cono Sur production, and it has become a less risky strategy. Hurtado said “ten years ago cork taint was quite high, about 1%. Now it’s really unusual to find cork taint; about one in every 50 bottles”, adding “we’re not dealing any more with cheap natural cork, we buy only really good natural cork.”

Further north, the USA market has always been a strong supporter of cork stoppers, and its fervour is undimmed as the latest figures from the Cork Quality Council (CQC) show. They report significant growth in the sales of domestically-produced wines stoppered with cork and selling over US$6/bottle.  With 15 months of off trade survey data of the country’s the top 100 domestic premium wine brands in the bank, the latest quarter’s sales, to February 2011, show a 14% increase in sales of wine stoppered with cork, while sales of wines stoppered with synthetics and screwcaps dropped by 13%.

Peter Weber, executive director of CQC said “I do believe that cork closures are preferred by consumers who also consider cork to be an indicator of quality.  Between consumer preference and improved quality I’d be surprised if this trend does not continue.”

That the cork industry has made progress was a recurring theme, and global share estimates seemed to have settled at around 70%.  Papa said “my feeling is that 7-8 years ago, everything appeared like there was one way – screwcap. Today I am not clear. Natural cork is again becoming more relevant and important, though they still have lot of work to do with TCA and TBA.”

Also part of this article are:
Forest Stewardship Council (FSC) certified cork stoppers
Recycling cork stoppers

Originally published as part of a longer article in the August 2011 issue of Drinks Business.

The USA’s huge market and strong preference for cork make it an ideal market for recycling. Cork manufacturer Amorim have an ongoing project there where recycled corks, from any origin, are re-used by Sole, a Canadian footwear company.  Since the ‘Recork’ programme kicked off in 2007, 16 million corks have been collected.  Carlos de Jesus, Amorim’s director of communications said “it’s mostly California and Washington.  It needs to be done in a financially and environmentally viable way”, there’s no point shipping a few thousand corks across states because it costs more than any benefit of recycling stoppers.

In mainland Europe, said de Jesus, used corks “are sent back to Amorim and incorporated in the production process of any non-stopper produce including floor and wall coverings, and aerospace applications”. He added the NH hotel chain “with properties throughout Europe have announced a partnership with Amorim to recycle corks.”

The scale of recycling is still tiny. Amorim recovered the equivalent of just over 1% of the company’s annual sales of cork stoppers.

The costs of shipping used corks across the English Channel can outweigh the recycling benefits. So in the UK it was Direct Wines/Laithwaites that picked up the recycling baton at the beginning of 2009. Anne Linder, development manager for Laithwaites Wines said “it grew out of recycling wooden wine boxes at a special needs school close to us, who make all manner of things such as trays and bird boxes. They were looking to grow that art and craft activity with cork.“

To generate a flow of material for the school there are now cork bins, taking all cork-based stoppers but no synthetics, in all Laithwaites shops.  Linder added they were able go further “because we have a small vineyard, so we put the corks through a garden shredder to use as chippings to suppress week growth and retain moisture. All the glue is food grade, so there’s no risk of anything nasty.” Word is spreading, because Laithwaites also collect the used corks from the Savoy Hotel, and now the Goring, in London, though the garden shredder is a personal option is available to all consumers with a garden or allotment.

The remainder of the original article can be found:
Forest Stewardship Council (FSC) certified cork stoppers
Reasons to choose stoppers

Mediterranean cork oak forest

Originally published as part of a longer article in the August 2011 issue of Drinks Business.

The Forest Stewardship Council (FSC) has been certifying Mediterranean cork forests since 2005, and by 2010 the certified area had reached nearly 72,000 ha, out of more than 2.5 mha of Mediterranean and North African cork oak landscape.

Certification means cork oak growers can supply to cork stopper manufacturers traceable cork planks from forests certified to adopt landscape-sustainable practices. Part of this sustainability includes forest regeneration to prevent the landscapes from eroding.

Vera Santos, the executive director of FSC Portugal said “Portugal has around 52, 000ha of cork oak forest FSC certified. It is expected that by August this year, the FSC certified area of cork oak forests will reach 90,000ha [due to] a new FSC group certification and some new members joining existing groups.” She added “the target is to have 150,000ha certified by the end of 2012.”

In Spain, some 30,000 ha of mixed forests, including cork forests, have been certified.

Across the two countries there are also some dozen cork manufacturing companies that are certified by FSC to produce FSC-certified products, for example cork stoppers. Amorim have been at the vanguard of FSC certification, but even for them it’s a tiny proportion of their total stopper production, about 10 million FSC stoppers out of 3.2 billion stoppers in total. de Jesus said with FSC there “could be as much as 20% more cost” and what started with single piece natural cork stoppers – the traceability and chain of custody was manageable – now includes technical stoppers and those made from cork particles such as sparkling wine stoppers.

As recently as a couple of months ago [sub – the timing of this comment is correct for August publication] the manufacturers of diam stoppers “applied for FSC certification, which should be available by the end of this year” said their vice president of marketing, Bruno de Saizieu. But, he added “demand is not huge, today it’s less than 1%”

In the UK, Sainsbury’s and the Co-op have drawn a line in the sand regarding FSC stoppers.

Clem Yates, winemaker and product technical manager for Sainsbury’s, said “own label wine accounts for one third of the wine range at Sainsbury’s and of that I would say 40% of those wines are under cork. We are already the world’s largest purchaser of FSC corks and use over 6 million corks per annum.”

Environment clearly plays a role in decision making.  Yates said “At JS, one of our core values is sourcing with integrity. This helped us decide to move all our own label cork stoppers to FSC.” This is a work in progress, initially moving existing cork stoppers to FSC cork.

Over at the Co-op, Ian Rogerson, their technical manager for beverages, said “As a business, we’re committed to using more sustainable packaging. The Co-operative has moved a large number of its own-brand wines with cork closures to FSC cork. We are trying to move as many suppliers as possible to FSC, on our own labels.”

He suggested supply had been a limiting factor, saying “When FSC closures first came on market, they were initially only available at very top end of the market”, i.e. single piece cork.  He said that regular level stoppers, and technical stoppers only became available about two years ago, adding “the quantity of FSC material available is now beginning to increase, so opportunities to pursue this option are becoming greater.”

The remainder of the original article can be found:
Reasons to choose stoppers
Recycling cork stoppers

Forget closure OTR (oxygen transmission rate) for the moment. In closing up a wine bottle, TPO (total package oxygen) is where the TLAs (three letter acronyms) are at, and the bottling operation is the bigger oxygen issue by far.

TPO is the sum of dissolved oxygen (DO) in the wine plus oxygen in the air of the headspace (HO), and whilst many folk have got their heads around DO, the idea of TPO is still relatively new.

Warren Roget, technical manger at the AWRI (Australian Wine Research Institute) said “normal bottling processes entrain oxygen in the bottle. There is oxygen dissolved in the wine, and there is oxygen in the headspace. Our work shows that 60 to 70% of the total package oxygen is typically contained in the headspace.”  What is concerning, added Roget, is that “it’s typical industry practice to measure DO in wine, meaning the majority of the oxygen in the bottle is not being measured.”  In practice he added, this means QA specifications may state permissible DO levels at less than 1mg/l, but when “you look at TPO, they may be closer to 3mg /l because they’re not measuring oxygen in the headspace.”  Wine specifications should be moving to detail TPO instead of the less relevant DO.

Measuring TPO has only been possible for a few years with the development of non-destructive (i.e. not needing to open the bottle of wine) measurement kits, such as PreSens, OxySense and NomaSense. Standard laboratory equipment only measures DO.

Importantly, TPO is a snapshot measure immediately after the bottle has been packed. “Three months after bottling” said Roget “the TPO will virtually all be consumed by the wine. It is from this point forward that closure OTR becomes the important factor in regulating oxygen intake into the wine. However significant quality and shelf life impacts may already have been incurred.”

Management of headspace is therefore one of the most critical areas for control of oxygen ingress at bottling.  Sometimes remedies are simple, though incur costs: using inert gases, for example nitrogen, or carbon dioxide, to flush out oxygen in the filling tanks, in pipework, the empty bottle, the headspace, prior to the wine being transferred.

According to closure trials done on riesling at Geisenheim Research Centre, Professor Dr. Rainer Jung found that after nearly a year, cumulative OTR varied significantly across screwcap and synthetic, from “0.5 to 2.5 mg/l in total, which is not very much.  It is not enough to oxidise the wine.”

But a different picture emerged with headspace trials. Jung said “we measured 6mg/l oxygen in the headspace. It takes about 4mg/l SO2 to reduce 1mg/l oxygen, so if you have 6mg/l of oxygen, you need 24mg/l SO2.” The first AWRI closure trial identified oxidative characters developing in white wine at about 10mg/l free SO2, and whites are commonly bottled with 30 to 40mg/l free SO2, so, said Jung “if you don’t want to lose of 24 mg/l SO2, flush the headspace [with inert gas].”

Jung highlighted the snapshot significance of DO and TPO, saying wine can arrive at the bottling line with 1-2mg/l DO already in the wine, though this completely depends on what has happened to the wine before, and its style. For example a micro-oxygenised red versus a reductively made sauvignon blanc. And he said, of a reductively made wine, where oxygen has always been kept away “in the last step, you pump into the bottling tank, and get the same amount of oxygen uptake. This will directly react with wine components, so no DO is measured, but the aromatics and phenols can be oxidised.” So the wine is in specification, but its defining characters have been lost.

Even some reds won’t benefit from oxygen at bottling. Stéphane Vidal, global oenology director at Nomacorc, said “syrah is quite reductive. If you add oxygen at bottling, you are simply wasting sulphur dioxide” and shelf life. He added that improving bottling TPO by 2mg/l “could save one year of shelf life of the wine”, if the bottle is closed with their Nomacorc Classic+, for example, which has a 2mg/l OTR over the course of a year.

Headspace management is also a critical control point for traditional method sparkling wine. Michel Valade, responsible for viniculture at the CIVC in Champagne said “the quantity of oxygen that might enter the bottle at moment of disgorgement varies according to conditions of disgorgement.” CIVC studies showed that the amount of oxygen introduced at disgorgement varies from 1 to 10 mg/l, and averaging 2 to 4mg/l.  Valade said that during ageing [sur lattes] “only 1 mg/l per year of oxygen enters the wine, and is consumed by the wine, so 2 to 4mg/l is the equivalent of 2 to 4 years of oxygen transmission through the closure.”

Valade explained “at the moment of disgorgement some bottles let some mousse escape, in which case there will be no oxygen entering the bottle [as the effervescence expels headspace oxygen]. But if bottle is very quiet, or stays a bit longer on the line, up to 6 mg/l may enter the bottle.” This clearly creates big bottle variation which will directly affect the flavour profile. 

The ideal is to have zero oxygen entering all bottles at disgorgement.  And to this end, the CIVC are developing a technique already used by the brewing industry, and, according to Valade, by some of the big Champagne houses, though the CIVC are still completing trials. A tiny amount (20 μL, or 0.02 mL) of wine is injected into the bottle under pressure, after dosage, immediately before the bottle is closed. This provokes the wine to effervesce, which expels the headspace oxygen. 

“Very soon” Valade said “this technique will be widespread in Champagne.” It “is not very expensive, and can easily be installed on the disgorgement line.“ Added to which, he said, achieving a close to zero ingress of oxygen at bottling means producers can use less sulphur dioxide, to achieve a lower final sulphur dioxide measure.

The level of TPO that industry should be aiming for depends on individual wine style, though “generally the lower the better” said Roget. Vidal said their studies showed “on average, DO is 1-2ppm mg/l. And headspace is 1-4mg/l, giving a TPO of 2 to 6 mg/l.” So, he said “A TPO of 2 mg/l is therefore already a good situation – a bottling line that is working fine.“

For the majority of wine which is drunk within two years of bottling, this is all crucial, as high TPO at bottling quickly erodes shelf life. And for these wines, the wine should be ready for drinking at the point of bottling.  Jung said “During bottling and storage the lowest quantity of oxygen coming into the bottle would be the best way to keep the wine in a ‘ready to drink’ situation.”  Roget added “a high TPO can have a shelf life reduction equivalent to 10 years of oxygen transmission through a Saran-tin screwcap.” He said it’s a “completely different order of magnitude with TPO versus OTR.”

It’s clearly time to focus attention on the moment immediately preceding closure.

CASE STUDY – Reh Kendermann GmbH Weinkellerei

Reh Kendermann (RK) moved from measuring DO to measuring TPO in March 2010, with the purchase of NomaSense equipment.  Their winemaker Phillip Maurer explained that some years ago their contract customers wanted to know about oxygen management, so “we started to measure oxygen input at all the different situations in the cellar – racking, filtration, centrifugation, blending, the whole bottling – tank, filter, filler, bottling line.” 

Measurement, by sampling bulk wine was relatively easy, enabling RK to control the whole process. Flushing pipes, tanks, bottles etc., and blanketing wine with carbon dioxide minimised oxygen uptake. But this only measures DO.

With NomaSense, the TPO is measured and the “main goal is to have a TPO in bottle below 2mg /l.” Maurer added that such a TPO measure is now included as standard in the wine specification for Black Tower and the Kendermanns wines.

Intel has become one of the best know brands of computer chips, and our lives rely on that ‘invisible’ piece of technology.  Just as wine relies completely on the closure, so should closure companies pursue the ‘Intel inside’ concept of quality perception? 

Such branding would be useful for industry to distinguish different brands of synthetics, of screwcaps, of cork-based products, but would it, even in some years’ time, give consumers appropriate reassurance? Oeneo’s Dean Banister said: “we wanted to do ‘Diam inside’ a few years ago but Intel have the trademark on inside” adding, “a problem driven closures have is consumers don’t know what’s inside and we absolutely want to differentiate our closure from plastics and natural [one-piece] cork.”

Stelvin - clearly branded at the top

There’s the thing … all screwcaps are not equal (how many of us are guilty of saying ‘Stelvin’ when we mean ‘screwcap’?); all corks, natural one-piece and technical, are not equal; and all synthetics are not equal (moulded, single extrusion, co-extrusion). So “before we talk about consumer awareness” said Malcolm Thompson, vice president, marketing and innovation at leading synthetic maker Nomacorc, “we should talk about industry awareness for closure brands.  There’s still a tendency to genericise closure types by cork/synthetic/screwcap.”

It’s time to get serious about the individual quality performance factors of specific closure brands. Can some specific brands provide a safe route to quality assurance (notwithstanding application issues; transport and storage issues etc.)?  Mark Coleman of Neocork, believes so, saying “given the number of low quality producers on the scene and the various inferior materials they may use to accommodate lower pricing, I think brand is a key proxy for ensuring quality” adding the closure brand “adds another level of assurance for the winery. Our goal is to ensure the winery and its customers can focus on the wine, not the closure.”

Closure disclosure

Having the manufacturer’s brand name or logo on each unit leaving the factory would be a start towards brand differentiation, but not even all the big manufacturers brand every unit. Bruno de Saizieu, commercial and marketing director for Alcan Packaging Capsules, which make Stelvin, said “we put Stelvin on 99.5% of our screwcaps.  There is an occasional specific order without the full name on it.” He added: “we want our brand name on our product: firstly it’s important to get our name on, secondly, it’s important for majority of our customers because Stelvin is a sign of quality.  It’s why we communicate about Stelvin, not Alcan Packaging Capsules.”

In the spirits business, said Anne Seznec, marketing manager for Guala Closures Group “our logo is important for traceability, and it’s an additional protection for the final consumer, to be sure he’s bought the original bottle with the original screwcap.”

With just two SKUs for wine in their portfolio, Supremecorq’s vice president of global sales, Simon Waller said: “Every single one [is branded] without exception. Inside each [mould] cavity our name is engraved, so our name is on the end of every cork.  It’s subtle branding, a reassurance for wine producers that they’re getting the real thing. If we’re selling through distributors and agents, we think it’s smart to have our name on our corks, it’s a guarantee that it’s our brand.”  

Diam

It’s a similar story for Oeneo.  Banister said for “the last two to three years, when it leaves the factory there’s a Diam, or ‘D’ on it, or ‘Mytik Diam’.  We’re not advertising product by putting the logo on, we’re taking responsibility. We’ve made a lot of noise about what Diam can offer. And there’s a lot of look-alike products, so if it doesn’t say its Diam, it’s not Diam.”

It’s manageable with seven SKUs, but the big cork companies offer thousands of SKUs effectively making whatever their customers want: length, coatings, grades for each of a number of different diameter stoppers; technical, single-piece etc. Plus different stopper qualities for bottles that sell between £3 and £3,000. Felipe Neves, sales director for cork manufacturer Alvaro Coelho said: “around 90% of our production is branded. We always try to have our logo [a stylised ‘C’], but we won’t sacrifice the sales. The logo is more a matter between winemakers, who uses who. If they’re happy, the referral is very important for us.” 

Twin Top - not often branded

Nor do cork giant Amorim brand each of the 3 billion stoppers they make.  Their communications director Carlos de Jesus, said: “we try to brand as much as we can, but the decision is ultimately made by the customer, not by ourselves.”  It’s a similar situation with Nomacorc, where Thompson said: “our preference would be to put Nomacorc on every closure, but some of our customers don’t want it.  Some of the larger wineries are focused on building their own brands, and want to use the surface area for that purpose. Other customers [are happy] with Nomacorc artwork.”

Quality Assurance

So the top suppliers in each closure sector brand completely or as much as they dare, but with such a fragmented closure supply base, several hundred companies deep, can wineries and influential retailers do more to ensure they meet tight quality assurance standards?

Banister is convinced wine producers need to take more responsibility. He said “it’s hard for suppliers to push other suppliers out of business.  The cheapest are there because they don’t have HACCP, GCMS (gas chromatography, mass spectrometry machines), QA, hygiene etc., which are expensive.”

But wine brand owners don’t take these decisions lightly.  Carmel Kilcline MW, wine development manager at Percy Fox said: “we’ve used screwcap on Blossom Hill for 18 months, and we’re planning to move Piat d’Or to screwcap in spring 2009 for quality reasons. Our monitoring of consumer attitudes suggest change is welcome. But it’s important to get the technical performance and consumer acceptance aligned.”  

The need to combine a good customer proposition and consistent technical performance is reflected at Sainsbury’s where Barry Dick, product technologist for beers, wines and spirits, is reviewing closure policy. He said: “at the moment we’ve got a myriad of different closures which are inconsistent in terms of customer usability, quality and performance, cost and environmental impact.”   

Not that one wine brand owner or one retailer linking up with one closure supplier is a good idea.  Kilcline said: “For ease of production, most wine producers will have at least two suppliers of packaging material. If any unforeseen issues occur then we have an alternative supplier.” Plus, having a number, even if it’s a small number, of preferred suppliers keep the competitive edge sharp amongst them. She said “the technical team decides closures and we have two or three different producers who have to meet strict technical performance criteria, including on the bottling line.” 

Nor does global producer Constellation have a single policy on closures. Simon Thorpe MW, vice president wine development, said: “it depends on destination market because we work in so many different markets, which have varying degrees of acceptance, understanding and interpretation of closures. For example Da Luca Pinot Grigio we automatically close with a screwcap from a quality and consumer perspective, but if we developed this into a market such as the USA, they would want a natural cork.” And he added: “for more premium brands, the decision is made on the style of wine, and what winemakers think is best for the product.”  

Communicating closures: B2B or B2C?

Not surprisingly, virtually all communication is with the customers – wineries, retailers – of closure manufacturers. The relationship with consumers is effectively one of invisibility, much like service in a restaurant – you don’t notice excellent service, but you really notice when it’s not good.  

Education is an enduring theme. Thompson said: “there’s still a hump to overcome in the industry with awareness and understanding. And there is an opportunity for wineries in branding. The closure can add additional credibility to wine brand on a quality basis. Quality closures allow winemakers to give consumers a consistent product.”  Waller agrees, saying “we have a responsibility to the category to educate wine producers and those who influence the choice of closure.”

It’s more pressing for the cork industry, which continues to lose market share. And it’s because the closure market is no longer an accidental monopoly that manufacturers need to turn more attention to communication, of all sorts.  Neves said: “the amount of money that would have to be spent on a consumer campaign would be too big for the benefit.” But, he added “we are losing time, our company is increasing sales, but our industry is losing sales because we’re not communicating.”

However, Stelvin has been active. De Saizieu said: “we were in Paris recently, comparing cork and Stelvin with consumers. We do an event per month in France and other countries, with final consumers or with sommeliers. And when they discover something, the first thing you do is talk about it with other people.”

Amorim have used social networking sites to target a younger audience with their ‘Save Miguel’ campaign, which, said de Jesus, “is about bringing the brand to consumer, using a well know actor. The full five minute video  has more than 400,000 views on Facebook/You Tube/flickr.”    

Though communicating directly with consumers is at an embryonic stage, brand leaders emphasise consistent technical performance will win the day. Thompson said: “when wineries start to transition to a closure like Nomacorc that guarantees a certain level of quality and consistency, they elevate the whole quality game. If you’re not following suit, you differentiate in a negative way.”

Have the investment and new product development measures taken by cork manufacturers during the last decade to better control TCA (the chemical that causes musty, mouldy taint in wine had any real impact on our perceptions of cork as an effective stopper?  

Lab research

It was Dr Christian Butzke, president of the American Society of Enology and Viticulture, (ASEV), who wrote in 2009, that TCA was no longer a major problem for the USA wine industry. As chairman and chief judge of the Indy International Wine Competition, he reported that less than 1% of the wines entered were noticeably corked.

Going some way to achieve this redefining position for cork closures has been the California-based Cork Quality Council (CQC). Before CQC members (cork manufacturers and suppliers) accept any cork lot into stockholding, samples are sent to third-party ETS Laboratories for GC/MS analysis (gas chromatography / mass spectrometry) of TCA.  They have reported an 80% decrease in the incidence of TCA contamination since 2002.

Since 2007, technical corks are also systematically tested, and reveal remarkably similar results to single piece stoppers. Peter Weber, the director of the CQC estimated “that our group now supplies about 80% of USA corks.”

Weber explained the early quick win for the CQC “When we first started chemical testing for TCA we enjoyed very quick improvement. Most of which was because we could now see what sources were supplying “good” corks. It was easy to instruct the manufacturers to redirect their purchases away from [less good] suppliers.  We probably achieved a 50% improvement from this type of adjustment alone.”  As manufacturers increasingly used high-tech equipment, the pre-screening process showed continued improvement.  

On the other side of the pond data is rarer, and an almost visceral mistrust of the cork industry’s ability to put its house in order appears to have developed in the past decade.

Cork harvest from tree

The picture for cork closures is also now blurred because a lot of mainstream merchants and big retailers moved away from cork-based stoppers into either or both synthetic and screwcap. Bottle Green’s wine director Nick Butler said “we have reduced natural cork closures in the wines we sell to less than 20%.”  It’s a similar picture at Alliance Wines, where business development director Fergal Tynan MW said “we moved almost all of our own production wines to screwcap some time ago, This remains our preferred closure, far from perfect but offering the best overall solution at the moment.” 

Whether retailers initiated this trend is a mute point.  Sainsbury’s winemaker Clem Yates said “over the past five years most of Sainsbury’s own label wines were either under synthetic or screwcap with little natural cork used in the range.” Direct Wines’ product manager, Martin Campion echoed this approach, saying “we are buying more wines under screwcap than ever before.” But added “we will continue to take the more classic wines under natural corks,”

Despite this loss of market share by cork stoppers, within the cork share of market there appears anecdotally to have been modest improvement, though monitoring of customer complaints is unreliable, and many retailers don’t attribute credibility to these data. Thierry’s winemaker and quality manager, Jeneve Williams, urged caution regarding false positive reporting of customer complaints, saying “cork taint is still an issue … though products such as Diam have made a difference to the incidence rate along with the efforts of the cork industry to improve quality of production processes”.

Thierry’s Burgundy supplier Mommessin supported a slight improvement. Their quality manager, Paul Correia said “‘we still do in-house batch testing on the corks because the R&D programs implemented by cork suppliers started only 10 years ago. The rate of cork taint has decreased – I rejected 4 lots in 2009, 4 in 2008 but 14 in 2007, so the quality has improved but cork suppliers have more to do.”

This leaves anecdotal evidence largely coming from tastings and observed experience, and carefully monitored wine competitions provide some clues.  Thomas Costenoble, director of the Concours Mondial de Bruxelles, where taint issues have been analysed since the competition started in 1994, said cork “problems decreased significantly, however we cannot say that TCA disappeared. This year 120 samples came back to the preparation room (~1.7% of the total) [all faults: TCA, oxidation, reduction, re-fermentation etc]. No more than 66 samples were really suspected of cork problems (0.9%).”

The International Wine and Spirit Competition (IWSC) have only more recently been measuring faults.  Competition director Frances Horder, said “we have measured requests for a replacement bottle, by closure type, for the last 3 years, and added fault types last year. In 2007 and 2008, 8.3% of bottles with natural cork were replaced, falling to 7.2% in 2009.  Just under half of these were identified as due to TCA, so 3 to 4% of the total. … anecdotally this year also looks better.”  So significantly different figures, but a slight downward trend.

This is confirmed by the more traditional merchant sector of the UK market. Patrick Sandeman of Lea and Sandeman said “I would confidently say that we have had far less of a general problem with corked wines over the past decade because the cork producers have finally realised that they had a problem and it needed sorting.” Anecdotally, at a recent Lea and Sandeman tasting, Sandeman said “of the 130 or so wines which we opened, of which upwards of 80% were under cork, we only came across one bottle which was very definitely corked.”  Elsewhere, Joel Lauga sales director at Great Western Wine and Ewan Murray, the head of tastings, events and PR at the Wine Society have guestimated reductions in cork taint from 10 to 20%.

Some positive stories have emerged. Yates said “we have recently reviewed the Sainsbury’s closure policy and we feel that the risk of TCA has decreased, so we’re in the process of working with Amorim to use a more sustainable FSC (Forestry Stewardship Council) natural cork in a wider range of own label wines.”

One or two others have revised their views on cork. Sandeman said “a decade ago we were very much in favour of Stelvin, but our attitude has changed back in favour of cork for many reasons – aesthetic, environmental, and quality. Cork will always be the best closure so long as it works, and increasingly it does so.” Waitrose buyer Andrew Shaw’s views on cork closures have “gone full circle – it’s once again seen to be the best closure if managed correctly”, but 60% of Waitrose’s sales are of screwcapped wines, so “reduction [a different type of wine fault] is a potentially greater concern.”  

Despite the promising news, hesitancy and caution remained the watchwords of the trade, with Lauga saying “the rate of infection, although better, is still too high to regain wide confidence especially for new drinkers. We still rate cork closures high risk.” Yates was similarly strident, saying cork taint “seems to have reduced dramatically from recent years, but there are still very dangerous levels of TCA which just dumb the fruit and are not obvious even to the trade so therefore still have a large potential to negatively influence the consumer.”

Cork taint is unequivocally still an issue.  Butler said “why invest so much in the wine, packaging, marketing and then possibly risk it all with a risky closure. Certainly my perception is that the cork manufactures have improved their systems, supplying better cork, more consistently BUT the vulnerability to random TCA issues persists.”

The message is clear from the UK.  The cork industry still has plenty of work to do.

Cork harvested from cork oak tree

In the last decade, each cork oak tree has been harvested only once. In the last decade the main cork manufacturers have taken seriously the issue of TCA (the chemical that causes mouldy, musty taint in wine). Consolidation has seen some players hit the wall, while the big boys have put big money into technology to monitor and clean up the raw material.

Proprietary cleaning technologies, mostly based on deep steam-cleansing of cork particles, discs and whole single piece stoppers are combined with multiple quality assurance checks in the manufacturing process to eliminate batches of contaminated product before they reach the finished product stage.

Also in the last decade other businesses have been enticed alongside the cork industry, providing new barrier technologies to modify cork performance.  After all, cork remains the most natural and sustainable stopper, and it has high consumer approval.

Such so-called barrier technologies that are now being added to the business end of corks have long existed in the food industry, and wine is, after all, legally a food.  The two main protagonists in the barrier technology game are Procork and Nanocork. Both tout consistent oxygen permeability as their main function, and both claim TCA reduction as a side benefit of the technology.     

Procork was first out of the blocks, and are now selling around 100 million units a year after their commercial introduction in 2002. The five-layer barrier acts as a TCA barrier, a flavour barrier and an oxygen barrier. Former CSIRO (Australia’s Commonwealth Scientific and Industrial Research Organisation) packaging, polymer and food sciences scientist, and founder of Procork, Dr Gregor Christie said “wineries using it stick with it because wines are better, stay fresh, keep character, don’t lose the edge which you get with oxidation, and don’t get a taint issue.“

He said “two separate, independent AWRI (Australian Wine Research Institute) trials have shown that coated corks outperform screwcap and natural cork” adding “we have a number of Bordeaux chateaux starting with Procork technology after 3 years of carefully evaluated trials.”

Source: AWRI Commercial Closure Trial 2002, 24 Months, Procork

Christie explained “we started the work with an oxygen permeability control layer. The TCA adsorber layer is a side benefit we came across. It’s not a barrier, it doesn’t block it, but TCA will soak into it. Two of the other layers are barrier layers, so TCA can’t get through those layers.” Christie said the crystalline polymers of the barrier layers also stop glue taint. He added “The layer in contact with the wine also needs to be crystalline to stop wine flavour being scalped into the skin.”

The quality of the cork remains important with similar choices as for non-membrane cork, according to wine style. Christie said “the cork has to seal the bottle. We decided to purchase corks so we can control that aspect of it. We use top quality cork for top quality wines. With quicker turnover we can adjust quality of cork.”  

The products in the Procork portfolio all have same barrier technology. Christie said “Platinum signature is our leading brand designed for reserve wines being cellared. This is top quality natural cork.  Procork blue is right at the other end, using an agglomerate-technical cork. Technically they perform very similarly.”

Whilst the membrane is produced in Australia, all the production and distribution is done from Portugal.  Corks are bought from big and small suppliers, all incoming lots meeting industry norms for quality control of the usual parameters such as TCA, sensory, density, mechanical performance.  The final product said Christie “is slightly less permeable than a good quality cork, and more permeable than a screwcap with SaranTin.” 

These are the same parameters for Nanocork, also produced in Portugal, under exclusive licence by the second largest cork manufacturer Alvaro Coelho, using the Bacchus barrier membrane.  In their 24-month trial of Nanocork, AWRI reported that, in comparison to a reference 2 natural cork, a Supremecorq X2 (top of the range), and a Stelvin SaranTin screwcap, the Nanocork was fresher and fruitier than the driven alternatives, and less reductive than the screwcap.

The Bacchus membrane, in development for cork since 2002, uses a polymer that has been used in the bag-in-box industry for many years, and more recently in flexi-tankers for bulk transport. Managing director of membrane producer Bacchus Wine Closures, David Taylor said “we use a separate adhesive which is excellent for bonding plastic to wood in wet conditions. It gets harder and stronger in contact with moisture.”

Having trialled the membrane since 2005, Alvaro Coelho adds the membrane to colmated corks. They signed up their first paying customers this year and are confident of market demand.  Henrique Figueridos, the sales director at Alvaro Coelho, said “this year we are expecting to sell more than 10 million. As orders grow we still can’t determine the final figure but it will be an excellent figure for a startup cork product. We expect to reach hundreds of millions in the coming years and our goal is one billion in a five year period.”

Figueridos asserted that the on-cost for customers is ‘tiny’. And Christie was equally bullish, saying “nobody’s not buying the product because of the price. We can match the prices that other people are selling at. “

The development lead times for such new technologies are not far short of the length of time the cork industry has been cleaning up its product, and the barrier guys are still early on the curve of potential take up, so time will tell if they become mainstream options for producers, but at least more options exist.

Equipment developed in the 1990s by NASA to keep fruit and vegetables growing and healthy on the space station has been found to remove airborne TCA – trichloroanisole, the chemical that causes mouldy, musty taint in wine.

Independent proof of concept trials by UK specialist drinks industry laboratory Corkwise found it removed 90 to 95% of airborne TCA within 24 hours.  The potential applications for the wine industry are manifold. Corkwise’s Geoff Taylor mentioned “anywhere that stores wine either in bulk or bottle. Particularly prone locations would be old cellars, warehouses where there is dampness, wood for example, old, expensive wine.” But, he added “even modern cellars can become readily contaminated with TCA.”

Alistair Thompson, general manager of Surrey Diagnostics, UK agents for the kit said: “Airocide works by photo-catalytic oxidation. Air is passed on bed of a titanium dioxide catalyst. This is irradiated by UV bulbs, and organic contaminants are oxidised.” Water vapour and carbon dioxide are the final oxidation products of organic compounds. A difference from filters is that filters trap things, whereas Airocide destroys them, leaving just CO2 and water.  

That Airocide doesn’t remove 100% of airborne TCA is explained by Taylor: “once a room or cellar or warehouse becomes contaminated, some TCA is readily absorbed into the walls, floors, ceiling and packaging materials. Wood and cardboard particularly act like sponges. As the aerial levels drop, trace levels of TCA are fed back into the atmosphere. The crucial point is the very significant reduction.”

Chateau Montelena in California has used Airocide in the fermentation cellar and wine library for more than three years.  Their winemaker, Cameron Parry said: “The cellar went from having a slightly musty smell, not surprising for a 127-year-old building that is half underground, to having virtually no aroma, and no musty tones at all.  Really the only thing you smell in the cellar now is the oak from the barrels and wine if racking is taking place. I am very confident in the Airocide units and do not have any fears about exposing the Montelena wines to the cellar air.”

A flurry of activity, mostly generated by customer demand for innovation, has seen several new closures on the market, both for premium and high volume wines.  TCA (2,4,6-trichloroanisole, the chemical that causes musty off flavour in wine) has given way to OTR (oxygen transmission rate); new stoppers have been brought out for sparkling wines, and marketeers are getting back on the act as closure choice becomes a way to differentiate brands.

Three new sparkling wine stoppers have appeared.

Three new sparkling wine stoppers have appeared. Alcan’s Maestro stopper has all the pizzazz Champagne could want, and it is built around the utilitarian crown cap, which frequently does the stopper-work in maturation cellars before disgorgement.  The functional cap is dressed to the nines with thick foil and the new one-arm bandit opening mechanism. 

The business bit of of the Maestro

Crown caps with synthetic liners have been used in Champagne for more than 10 years. Maestro uses a single piece liner of “unique shape that gives it a better sealing, with a thicker layer of polyethylene” said Mathias Mélan Moutet, president of cap-maker Solocap-Mab, which, he said, gives it a CO2 loss well within the lowest third of the CIVC’s ‘acceptable’ range.

Bruno de Saizieu, the commercial and marketing director of Maestro-maker Alcan Packaging Capsules cheekily smiled “the effort to open it is easy enough for a woman to do”. The opening is made simpler without the foil to unwrap and the wire to unwind. Restaurants should love it.

Australian company Zork has brought out a plastic stopper for sparkling wine, based on the technology for its still wine stopper. It comes at a cost they say is comparable to cork-plus-wire, but, said marketing manager Jo Baker “the big cost saving for producers is to opt for no [foil].”

Zork sparkling

Evans and Tate have used this on their new sparkler Zamphire.  Rosemary Scott, their general manager for global sales and marketing, said “the re-sealable closure appeals to consumers as it allows them to have a glass or two, reseal the bottle and save the rest for another day. Equally, almost 50% of Australian sparkling wine consumers who we surveyed said they found it difficult to open bottles. The new closure allows more control when opening while still providing the traditional ‘pop’ and ceremony.”

The semi-sparkling (frizzante) market is big in Italy, and Guala Closures has brought out the ‘Moss’ (Italian for slightly fizzy) screwcap for semi-sparklers. Marketing manager Anne Seznac said the screwcap “was used for small formats, but not for big formats until requests came from Italy, Argentina and Brazil” for something easy to open and close for younger consumers.” A polyethylene liner was developed, but the shell of the screwcap and the bottle are the same, so, she said, only an adjustment to the block pressure of the capping heads needs to be made.

With Prosecco resurgent, as well as semi-sparkling usually attracting a lower duty rate in the UK than sparkling, this could be an interesting development, although Neil Bruce, wine director at Waverley TBS said he would want to know “firstly, if we have a need for a semi-sparkling. Is there enough innovation in the wine?” With 85% of Waverley’s business being in the generally slow-to-innovate, fragmented on trade, he added innovation in the on trade “tends to be supplier led.”

'Moss' screwcap for semi-sparklers

For still wines, a number of premium products have been launched and brand differentiation is emerging as a consideration for choice. After nearly five years without reported quality issues, glass stopper Vinolok’s general manager Siegfried Landskrone said the stopper’s “attributes combine the oenological standpoint of a proven system, and it meets the aesthetic view of a new trend for customers – it’s easy to open, there’s no extra tool, it’s a more modern and fashionable way, and it meets the emotional requirements for how a closure should look.”  

Landskrone said: “Vinolok is moving from a purely technical solution, where the main contact was the winemaker.  In the last 18 months this has changed to the sales and marketing guys. Where people are producing wines for export, more wineries are looking for marketing strategies to makes attractive packages.”  He added in terms of cost Vinolok is comparable to high quality natural cork, so it’s not an option for many.

Peter Gago, chief winemaker for Penfolds agrees that “aesthetically and psychologically people have a lot of trust in glass.” Indeed Penfolds are at the very early stages of trialling two prototypes of true glass-on-glass stoppers, though phase one is not yet complete, Gago’s confidence notwithstanding: getting a glass disc appropriately fixed onto the levelled top of a bottle. If this development is successful, said Gago, “it will be for wines meant to age long term, the upper end of our portfolio,” adding “the proof is we have bottles [Grange] under this seal for over a year now. It’s working.”

Another product aspiring to the premium niche is Econatur from cork producer Juvenal. Cork is undeniably the most environmentally-friendly wine stopper, and Juvenal have amalgamated cork harvested from their 600 hectare organically-certified forest with cork from FSC-certified forests to produce a range of corks they market as ‘chemical-free’. 

Econatur one-piece cork

Rui Pereira, sales director of Juvenal said “the idea had been just to do single-piece cork, but there was pressure from customers to include technical corks”, which has already given Juvenal orders for 1m stoppers.  

At the high volume end of things, cork giant Amorim have re-launched a single-piece cork stopper, targeted at the fighting end of the market where clients want whole cork not technical (cork particles/discs of whole cork), but have not been able to afford it. It is cited as being able to undercut the alternatives by up to 50%. 

Communications director Carlos de Jesus said Aquamark is a single piece “lower quality natural cork stopper wrapped in new technology, which is sensorially neutral and has a visually-appealing result while keeping costs at a price point that brings natural [single piece] cork stoppers to price sections from which they were previously excluded.”

The price range was given between €35 and €110/1000, and de Jesus added: “Since we launched five months ago, 100 new clients have started using it, including some brand new customers.”

Acquamark stopper

The cost competitiveness of such a product may be the only thing that gets the UK trade interested. Matt Dickinson, director at Thierry’s said: “I look at [innovation] from two perspectives: what will the consumer think, and what will our customer think? And what about the cost? Can we benefit because of the cost, or for profile?”

He explained: “For cost and profile, commercially it depends on type of product. If mass market, finding as perfect a closure as possible for as little as you can pay is the route to go down. Any saving we can make on any aspect of packaging is a good thing, especially if it improves the overall quality of the liquid.” But, he warned. “the consumer is key to all this. If they don’t accept a particular type of closure, you need to find ways of bringing them on board.”

A different strategy has been adopted by Nomacorc who are working with scientific institutions to understand oxygen management throughout winemaking to arrive at “the sensory profile of the wine that the winemaker wants” said Malcolm Thompson, vice president of marketing and innovation, adding “OTR is one aspect. We have learned that oxygen management upstream is critically important. Ultimately we’ll look at pre-bottle ageing, micro-oxygenation and try to bring the whole process under control.” Adding “we’re aligning the research to our closures, and we can imagine a range of closures with different OTRs.” In the meantime their customers get valuable insight.

Such total control for reliability and consistency should elicit the interest of the big brand owners. Though, having adopted screwcaps 18 months ago, Greg Wilkins, director of Brand Phoenix, owners of First Cape, said: “for brand owners, consistency is the most crucial factor. We evaluate new closures periodically [but] we’re fairly conservative. Once we’ve found one that works, then the person who is the most important is the consumer.”

Pernod-Ricard’s wines development director, Adrian Atkinson was equally circumspect, saying: “Whist we do keep up to date on new closures, we have put a lot of time and research investing in screwcap closures – it is a commercially viable investment for Jacob’s Creek both now and for the foreseeable future.”

Ultimately, no matter the innovation, it has to stand firm with consumers. David Gill MW, director of Bottle Green said “It’s all very well if we or the retail buyer thinks it’s a good idea, but will the consumer buy it?”

Oxygen ingress has become the new black for the closures industries.  TCA (the  mouldy, musty taint in wine) is last season’s outfit, and environmental considerations remain an underground movement, threatening to move into mainstream fashion at any moment. 

In its efforts to forge an environmental path, cork closure champion Amorim held a seminar on the sustainable future of natural cork, presented by Dr Miguel Cabral, their research and development director. According to communications director Carlos de Jesus, the seminar covered “anything that people want to talk about – carbon footprints, the latest research and development, TCA, new products, new oxygen permeability research.”

But cool chic is all about oxygen management, and OTR (oxygen transmission rate – how much oxygen passes through/past the closure into the wine) is the new three-letter acronym of closure cool.  It’s during the last year or two that oxygen ingress through/past the closure has quietly become the accepted norm.  Screwcaps are no longer considered hermetic by the mainstream, though it is difficult to pinpoint the origin of this, as the Stelvin brand of screwcaps have been available with two differently permeable liners for more than 30 years, and, according to Bruno de Saizieu, sales and marketing director of Stelvin makers Alcan Packaging Capsules, have been marketed as such.  

Why is OTR so ‘of the moment’? Managing oxygen is related to the mechanical and physical properties of the closure in contact with the bottle bore or top of the neck. Closures need to be consistent, and, by and large, it is the industrially made closures, where each and every one is the same as the others in a batch, that are likely to perform most consistently. With such consistency of closure, and therefore, it is thought, of OTR, trials and observations can be made from which wine behaviour in bottle can be predicted with confidence.  Dean Banister, the sales director for Oeneo, who make Diam, said: “at Oeneo we’ve been talking about OTR for a few years now and for us it is the next big issue for closures. For me the subject is being led by Oeneo and Nomacorc because we can both actually control OTR with our closures whereas it is not possible with natural punched cork.”

Indeed, earlier this year, synthetic stopper supremo Nomacorc, with G3 Enterprises and Lallemand, founded O2inWines, a group bringing together industry technical leaders to expand science-based understanding of oxygen’s relationship with wine. Inter-Rhône has just become the fourth industrial member of this Association, alongside academic members such as AWRI, INRA, UC Davis and Geisenheim (institutions in Australia, France, USA and Germany respectively).

Nomacorc’s vice president, marketing and innovation Malcolm Thompson, said: “there’s quite a buzz associated with the whole oxygen management in winemaking. Some as a direct result of the conference, a lot of it as a result of work Nomacorc has done specifically”, which includes four initiatives with leading institutes across the world, researching the effect of oxygen on different grape varieties and bottling conditions.  He added “the research is step by step globalising, with four programmes at AWRI (the Australian Wine Research Institute), INRA (the Institut National de la Recherche Agronomique) the Geisenheim Research Centre and UC Davis. And we’re nearing a position to announce a fifth programme in south America.” 

PLASTICS

As well as OTR research initiatives, a new model of Nomacorc closure – Classic+ – has just been released, after a three year development programme. It has an OTR about 30% lower than their Classic model and Thompson said: “the Classic+ driver is from performance to preservation. We’re capitalising on breakthrough technology when we developed Premium.”  Classic+ adds another 12 to 18 months shelf life compared to Classic.

Nomacorc may have five different models on the market, but competitor Neocork  have adopted a different paradigm, with just a single product. Mark Coleman, their director of global business development, said with: “a decade of commercial performance in the marketplace, we’ve been reluctant to start compromising a proven formula because when you start changing materials or densities on such a technically engineered product, there will be compromises.” He emphasised their single product met the age-ability needs of 85% of the wine market, that is, drunk within a couple of years of bottling.

But trials are under way, he said “to address market demands of both a lower cost cork and one more suitable for wines intended to age five-plus years with products whose densities, mechanical and sensory attributes mirror the proven performance of our current product.”  Expect some news in late 2009/early 2010.

SCREWCAP

A similar time frame is forecast for news on new screwcap liners. At least two types of liner are undergoing trials, one with an OTR between the two existing liners on the still wine market, Saranex (higher OTR), and SaranTin (lower OTR), and one with a higher OTR than Saranex. 

At one of the leading screwcap manufacturers, Guala Closures Group, different types of testing has involved different materials. Their marketing manager Anne Seznec said: “we’re working on a liner with a 100% hermetic closure because we need to achieve an hermetic seal first, before we decide the rate of OTR that we want to put in the liner.”

Alcan Packaging Capsules vie for global top dog slot with Guala Closures in the long skirt screwcap market. De Saizieu said “we are making some trials with customers on finished products. We’re testing regularly those liners to be sure that what we expect is right with the wine. But this takes time because of the ageing.”

CORKS

While both synthetic and aluminium closures are industrially made and therefore batches are expected to be consistent, natural cork, being natural, is argued to have some variation.  Single piece natural cork is still the most widely used cork closure with Amorim alone making about 1 billion of them, but, being single piece natural corks, they’re naturally subject to individual variation, though the amount is widely, and often inaccurately, debated. A two to three-fold variation is oft-discussed among academics, and there is also an argument that the high level of cork compression inside the bottle neck bore eliminates much of any natural differences between individual corks.

It may be difficult to offer a precisely measured OTR parameter for natural whole-piece corks, but it should be possible on high quality technical corks, such as Oeneo’s Diam, even though we don’t yet understand what a specific OTR means in terms of wine development in bottle.  

Nonetheless, OTR becomes a relevant topic of conversation to further that understanding.  Since the launch of Diam in 2004, Banister has been doing his bit to move OTR up the agenda. In fact, he said “we have not produced natural punched cork for over two years and we ended supply of this product in most markets at the end of 2007.” He added, “We will be a single technology company in the next few years, focusing only on the Diam technology” which means their ‘Reference’ product will be gradually phased out.

PROCEED WITH CAUTION

With Diam, Oeneo offer four levels of OTR, which, Banister said “because of the low understanding of the effect of OTR on wine we offer them on the basis of wine ageing potential [shelf life].” There’s also a differential cost “because of the density of each closure and the size of the cork grains.”

Carlos de Jesus says Amorim’s technical granular cork Neutrocork is their fastest growing stopper, though it’s long way behind the volumes of twintop.  On the various merits of single piece versus technical cork, he said: “Cork offers different products for different price points for different wines. You wouldn’t cross a desert with a 2CV [car], you might want something better adapted. We’re creating different products for the market, which is becoming more segmented. No one else can cover so many price points, we can offer something for £1 bottle or £1,000 bottle. 

And he doesn’t think the single piece natural cork stopper will fall out of favour any time soon. Using Bordeaux growths as his example, he said “If natural cork stoppers did not give you predictability and consistency, natural cork would have gone long ago. There has to be some consistency, there is a common sensory thread running through [different bottles of the same] wine.” He has a point. High level blind tastings would be tricky without some consistency across the board.

Though our understanding of oxygen management is at a foetal stage, OTR  and the closure is only one aspect, albeit a crucial one, of many, involved in managing oxygen. Before bottling, management through the vinification process and at bottling are crucial.  And oxygen ingress rates are affected by environment throughout the supply chain, from point of bottling to the consumer shopping basket and beyond.   

The reality is that we don’t yet know which level of OTR is good for a particular country or grape variety, or vintage, or vinification method, or bottle age. As Banister said: “”Do we really understand OTR, in short no not yet. Much work is being done on this subject and we know it matters but as yet it has not been quantified, so many variables, wine styles, winemaking style, expected consumption date etc. And remember that oxidation to one person can be seen as nice development by another.”

Consumers prefer glass bottles. And most Brits believe glass is an environmentally friendly form of wine packaging; more than for any other type of drinks packaging.  Innovation in wine packaging is rife, but what about the actualities of recycling so-called recyclable alternative packs.

As part of the drive to damage the environment less, weight is being designed out of packaging. Government-funded WRAP, the Waste Resource and Action Programme, has been driving the light-weighting of glass bottles, which so far remain consumers’ unchallenged favourite packaging format. By taking out weight, fewer carbon emissions are created during manufacture and transport. Part of the initiative includes shipping wine to the UK in bulk containers, and bottling in the UK at specialist bottlers. One whole container shipment can be saved this way.  Transporting one container of bulk wine is the equivalent of two containers of bottled wine. 

But a study by Reh Kendermann has shown there may be a greater element of sustainability to bulk ship to Germany, bottle there, then ship on to the UK. Their research looked not just at carbon emissions, but also how much recycled glass was used e.g. 34%, on average, in the UK, versus 90% for green bottles at Reh Kendermann, and energy sources – the UK average is just 4% renewable energy, and RK uses 16%. Their export sales director, Alison Flemming MW said: “There are obvious savings to be made when not bottling at source for new world wines, but perhaps it is not so well known that Germany has a distinct advantage in terms of reduced carbon emissions thanks to using the Rhine for transportation, as well as more effective, renewable energy use. We work with a number of partners in the UK and around the world on this basis.”

Can do

Rexam, makers of cans, have also been busy. They’re responsible for the recent launches onto the UK market – Wild Pelican, Elkan, Black Tower, as well as some prosecco brands.  John Revess, their marketing director said: “Consumer research showed young female consumers in England find the concept and product delivery of wine in a can appealing.  It’s light, it’s practical, it’s non-masculine. For sparkling white, why open a whole bottle, when you have the correct serving size.” 

He added, with the “number of single households increasing, single serve wines in 187 and 200ml are convenient. And cans are the most recycled drinks container in the world.”

The 18.75cl/20cl slim-line Rexam cans are well differentiated from a beer or carbonated soft drink can. But it is the Rexam fusion bottle that has been making waves recently. Stephen Howell, their breakthrough innovation manager said the “fusion can is new for the industry. We wanted to create a brand for the bottle, rather than create another can. We’ve fused standing can manufacture with a unique necking facility to produce something new and dynamic. It’s taken about 4 years in development and more than €4m in a pilot plant.”

Howell said there’s no reason not to use this for wine as well as other products. Only in May was the pilot plant opened, with the aim for full commercialisation by the end of 2009. Clearly the impetus for wine in a can could not wait that long.  As thought predicting success, a75cl fusion bottle is already on the drawing board.

On the technical side, as with bag-in-box and composite cartons, an internal food-grade barrier lining is required to prevent metal pick up by the wine.  This is the same coating used for other drinks, just thicker for wine. And on the oxygen front, still wines are dosed with liquid nitrogen which expands and pushes out the headspace oxygen immediately prior to sealing on the lid. It also gives a rigid feel to the filled pack.  

Yvon Mau’s new brand, Jolie Terre, has overcome the squat PET bottle as ‘wine-stubbies’ equivalent, with an elegant, slim PET bottle, which is just as tall as its glass bottle equivalent. Technology is key here too. Their CEO, Philippe Laqueche said: “we are using a single layer barrier which has been improved, and we will use a [further improved] multi-layer barrier later this year.”

Perfectly proportioned portions?

Wine cans of 20cl for sparkling and 18.75cl for still fit the single serve idea perfectly. To this end, The Company of Wine People have brought out a 25cl pouch pack for Arniston Bay, following on from the success of the 1.5 litre pouch last year. The company’s brand and trade marketing manager, Felicity Billington, said: “we launched the 250ml this year to broaden the appeal to a different sector. 250ml is more for the convenience sector, for travel and events, festivals and sporting events where you can’t take glass into arenas; for catering and airlines. It’s much lighter to carry and it’s flat once empty, so less weight and space is use on board.”  She added women especially were interested in the concept.

Recycle

Of the three ‘R’s (not reading, ‘riting and ‘rithmetic), but reduce, re-use and recycle, a lot of energy has been invested in the first R, with lightweight packs of all descriptions.

Pouches and composite cartons such as Tetra Pak, SIG Combibloc and Elopak are evidently single use, but the re-use of glass drinks bottles is not currently on the agenda.  A reversion to the 1970s deposit system would certainly remove the high level of energy required to re-melt glass cullet to make new glass bottles, but it’s not so simple, said Rebecca Cocking, recycling manager at British Glass: “returnables are heavier, they have to be designed to go through up to 12 washes. The collection, transport and distribution and wash side also needs to be considered. There’s not necessarily a saving to transport empty bottles to a filling point.”

Despite energy-intensive production for, among others, glass containers, Cocking argued: “our raw materials are abundant, they’re readily available in the UK. If you do a life cycle assessment such as WRAP’s glass versus PET, the carbon footprint is not that different. Glass is indefinitely recyclable, and it doesn’t lose purity from the closed loop.” Closed loop recycling is where a glass container is recycled into a glass container. But it occurs only where glass colours are kept separate, so mixed kerbside collections, which meet Local Authorities weight-based packaging reduction targets, do little to promote the best practice of closed loop recycling.  

It is plastics recycling which came on in leaps and bounds during 2008, especially for composite cartons. Prior to this, said Andy Dawe, WRAP’s head of retail programmes “even though PE (polyethylene), HDPE (high density polyethylene), and PET are recyclable, they tend to end up in landfill because there’s nowhere to recycle them. But In last few years, Local Authorities have put in the infrastructure for HDPE and PET bottles.  Over 90% of LAs now have plastic bottle collection facilities.”

And some plastics fit well the closed loop model.  Dawe said: “PET/HDPE can now be put into closed loop recycling system. About half a dozen new plants are under construction in the UK to process material.  Empty bottles currently go to Europe, are processed, and plastic pellets come back into the UK for re-use. ”

Recycling of composite cartons has long been an issue. The need to separate the card from the plastic from the metal creates challenges, and even up to the end of 2007, composite cartons were one of the ‘recyclable’ materials that couldn’t be recycled in the UK. Germany though, manages to recycle 65-70% of its cartons.

However, said Richard Hands, chairman of ACE UK, the trade association for composite cartons said “a huge amount has happened on collection. We had little collection a year ago. Now 83% of LAs have carton collections, run by the carton industry. We have used a paper mill in Sweden which was extracting the cardboard for plasterboard liner, and recovering the plastic and aluminium as energy to power the mill. We’re expecting to shift to a mill in Norway which has a fully recycling solution,” and which uses a high proportion of renewable energy. This, he said, more than offsets the transport costs from the UK in terms of life cycle impacts.

Sustainable Consumption Institute

Without comprehensive life cycle assessments which consider not just carbon footprints, but also wider sustainability issues, it is difficult to gauge the relative merits of one system/product over another, and decisions are never linear.

The Sustainable Consumption Institute (SCI) at the University of Manchester was set up last year, funded by Tesco, to look at some of the challenges. The SCI is undertaking academic carbon footprint studies on different types of drinks packaging – looking at industry averages for various types of packaging. Professor of sustainable chemical engineering, Adisa Azapagic, is leading this research. She said: “we’ve concentrated on the carbon dioxide equivalent emissions of the six main gases. Other sustainability aspects we are looking at include environmental impacts such as acidification, ozone layer depletion and eutrophication. But economic and social aspects are not included.

“The questions are very complex. This is industry average study,” Azapagic said, “you can come to opposite answers depending on what specific issues you took into account. When we do the specific pack analyses, the results could be different.

“And you can’t base decisions on one criterion. Image is important. If, for example, whisky manufacturers could be persuaded to bottle in green glass, we wouldn’t have a surplus of green glass in this country. 

In the end, consumers will decide their preferred packaging, and carbon footprints or wider sustainability and recycling issues may form only part of our buying behaviour.  Glass remains the favourite and it’s the only pack that’s fully inert, not requiring internal coatings. But, as with the screwcap initiative, industry is driving the innovation and watching what consumers like

RECYCLING CLOSURES

Closures make up only 1-2% of the total wine pack.

Alupro, the industry organisation said “The lacquer or coating is burnt off in the de-coater after shredding, before re-melting in the same way as the paint on the exterior.  The screw caps go off for reprocessing, via a metal processor to remove the plastic cap from inside the lids and then on for recycling.”

Amorim’s cork recycling trials in 2007 in the USA and Canada exceeded expectation.  Carlos de Jesus, director of communications said “we targeted 1 tonne in 12 months. In 8 months we’d already collected two tonnes. We were overwhelmed by the positive response, and we need to put in place the right logistics.”  He added: “In the UK, we’re in conversation with a leading retail chain to launch what will be the first natural cork recycling programme. We’ve established the CO2 impact of shipping corks back to mainland Europe and that impact makes the exercise worthwhile.”

The position on plastic stoppers is unclear.

Cork oak landscape

Cork forests have a wealthy biodiversity, reaching up to 135 plant species per square metre. This alone makes them an important resource for the planet. But cork oak forests are also managed landscapes, so key concerns for the WWF are to achieve an environmental, social and economic balance in them. They argue “over the last decade, damaging policies, poor forest management and a change of the cork market have resulted in the degradation and loss of these unique habitats,” suggesting the biggest threats are man-made: overgrazing, over-harvesting, over-conversion to agriculture, over-clearing forest, and simply abandoning the land.

That cork trees are harvested only every 9 to 12 years, and only after the tree is already at least 25 years old, means cork tree husbandry is a multi-generational issue.  For cork stoppers, the first harvest cannot be used as the quality is insufficient, so a tree will be around 35 years old before it first becomes potentially useful for cork stoppers. It is worth the wait, because cork stopper production accounts for two-thirds of the total value of the cork market, other uses including flooring, insulation etc. It is probably for this reason that the WWF has targeted the wine industry.

In the meantime, income must be derived for cork forest owners. It is their portfolio of activities, usually comprising stopper production, hunting, agricultural crops such as pine nuts, cheese and honey, and livestock grazing, that has the potential to damage cork oak landscapes.

Cork oak tree regeneration is the big issue, whether natural or by artificially planting seedlings. Hunting is profitable, and the temptation is significant to graze more livestock than the delicately balanced forest landscape ecosystems can tolerate. Cork oak seedlings are fragile things which need many years to establish themselves. Too-frequent hunts and too many livestock prevent them from establishing, and as few as one cow or three sheep per hectare can be too many. WWF say the number of livestock is not regulated, but that it may need to be in the future. Conservation of landscape biodiversity in conjunction with an economic return is no easy ask, but at least the WWF are evaluating cork forest landscapes as entire natural and cultural ecosystems which should enable a clearer picture of all the elements of management and landscape to emerge.

2006 marked the ten-year anniversary of the Quercus Project. Its findings and report arguably marked a seismic shift in the sensibilities and responsibilities of the cork industry. The extent of reformation and revolution in the cork industry in those ten years was wide-reaching, and still continues. 

It feels as though we’ve known about TCA (2,4,6 trichloroanisole – the chemical compound that causes ‘corky’, or more accurately musty/mouldy taint) forever, but when Quercus was being put together in the early 1990s, it was not known if TCA was one of a range of agents responsible for off flavour, a minor player, or the main culprit. Quercus demonstrated how TCA could be formed, and that it was indeed the villain of the piece: 80% of musty/mouldy taints implicated TCA. The cork industry knew definitively where to focus attention and investment. Before this, it had been thought that taking chlorine out of cork manufacture would solve the TCA issue, until it was later realised than chlorine is ubiquitous.

But the cork industry was only just beginning to consolidate into a more vertically-integrated structure. Antonio Amorim, chairman of APCOR, (the Portuguese promotional body for cork) said: in the early ’80s, the cork business was configured so cork manufacturers were completely separated from the reality of the market. There was a clear separation between cork manufacturers and cork distributors, the latter being in touch with bottlers and having access to wine requirements. It was not clear that any technical issues raised at the time were in fact technical issues, but rather commercial, negotiation issues.” He added: “In the ’80s we were concerned with the physical and mechanical properties of cork stopper. It was only from early 90s that some larger manufacturing companies began taking control of importers/distributors in the consuming markets and by the mid 90s vertical integration was taking effect; we were dealing with winemakers regularly, getting feedback and access on a direct basis.”

So Quercus set out to identify the agent(s) responsible for off flavours; to identify what stages in manufacture these agent(s) were generated; to produce a strategy for cork stopper manufacture, and to produce a protocol and control measures for cork stopper manufacture. Essentially Quercus undertook a hazard analysis of cork manufacturing. Sofia Afonso, one of APCOR’S technical experts, said: “we can consider Quercus was the first step for developing control methods for TCA.  It was the first time people began to talk to each other in scientific way. It was one of the foundations to control methods and research for several studies that followed.” 

It’s most immediate success was the drawing up, through CELIEGE (the European Cork Federation), of the International Code of Cork Stopper Manufacturing Practices (ICCSMP). Though a voluntary code, it was the first attempt to lay down best practice in cork stopper manufacture, across different producing nations.  The ICCSMP code is now in its fifth edition (2006), with protocols updated to reflect new best practice, for example, cork stoppers not to be transported with materials likely to contaminate them.

This was followed, in 2000, by Systecode: a third party accreditation system that audits companies working according to the ICCSMP.   It’s estimated that more than 90% of cork stoppers are now made according to the code.

Sainsbury’s were one of the original partners of Quercus.  Howard Winn, their quality manager for beers, wines and spirits at the time, said “the cork industry realised it was watching its market disappearing. The Quercus Project was a good starting point. It catalysed a raft of things. Some of its recommendations were fundamental things which weren’t happening before.” 

By focusing on critical control points in the manufacture of cork, Quercus identified ways to eliminate and minimise risk, some of them very basic: not using the bits of cork bark nearest the ground as these to have the highest incidence of TCA; eliminating from stopper production cork planks contaminated with ‘yellow stain’ (which had a high concentration of TCA); keeping cork planks off the forest floor, and off bare ground; removing treated wood from the manufacturing process, for example, replacing wooden pallets with metal ones; and controlling the water used during the boiling phase.

Martin Hall director of food science at Campden and Chorleywood Food Research Association Group, and the original Quercus Project co-ordinator, said: “Quercus laid the foundations for technological development and innovation especially with boiling processes.  Innovations in boiling processes have largely removed the need for post-boiling stabilisation. Planks are now racked so there is less compression, significantly reducing the amount of water taken up into cork. This has reduced the amount of time for post-boiling stabilisation.  Also, water is re-circulated after each boil [to remove volatiles such as TCA extracted from planks,], etc. The process is now largely in the 21^st century.”  Passing the water through heat exchangers ensures the temperature is a constant 98-99°C throughout the hour-long boil, where previously it had been a static system – no circulation, dropping water temperature, no removal of volatiles from the water.

Over and above this have been proprietary innovations occurring later in the manufacturing process – DIAM and ROSA are the obvious examples. Brand-specific extra cleaning and processing technologies which remove even more volatiles compounds.

Hall believes the key things over the last decade have been “the acknowledgement and acceptance of the issue, and one that could be dealt with, and the foundation given by the Quercus Project with the boiling processes and the code of practice.”  He singled out Antonio Amorim as a prime activator of change saying change would not have happened without such visionaries.

In the immediate aftermath of Quercus, both the Altec (Sabate, now Oeneo) and Twintop (Amorim) brands or cork closure were launched. Even before Altec met its demise, Oeneo were working on supercritical carbon dioxide. Dean Banister, their commercial director, said: “investment with supercritical carbon dioxide started eight years ago. Capital investment was completed in 2000: research, the pilot plant and validation, and getting the technology right. It took two to three years to adapt supercritical technology to suit cork, getting the ratio of pressure and temperature correct for cork rather than coffee.”

The Natural Cork Users Group convened early in the new millennium – an ongoing technical dialogue targeted to drive down levels of mustiness in wine. The group addresses itself to international standards, quality improvements, and the exchange of expertise, and counts over 60 members of technical experts, trade representatives and research personnel. It was the first time that the supply chain – retailers, industry associations, technical institutions, and the cork industry – came together in a technical forum with the intent to work together.

The frontiers of technical research and innovation in cork continue to be pushed. Scientific research is ongoing in some two dozen or more institutions in a dozen or so countries, all of which developed work since Quercus reported. Barrier technologies such as Procork have been developed; management and control of closure permeability are high on the agenda of all closure manufacturers; new types of technical cork binding materials are being researched; the idea of cork as a positive flavour contributor, like oak, may not be so far away.  Banister said: “supercritical has identified another 180 compounds that it extracts such as vanilla, terpenes, benzenes. By adjusting pressure and temperature and time we can leave in x and y.  TCA comes out pretty fast, other compounds take longer to extract.”

Quercus found TCA was involved in 80% of musty/mouldy taints. That still leaves 20% coming from sources other than TCA. We now know some of these are TBA (2,4,6-tribromoanisole), and TeCA (2,3,4,6-tetracholoroanisole). We also know the omnipresence of chlorine has compromised entire wineries with TCA contamination, no connection with cork.  This is another of the frontiers to be approached.  

On the environmental front, one of Quercus’ objectives was ‘to ensure the viability of cork forestations in Europe’. Ten years on, the WWF (World Wide Fund for Nature) report has emerged to refocus attention on the environmental aspects of cork oak landscapes. And fortunately for the cork industry, WWF are addressing the wine industry, challenging it to use more natural cork stoppers for the sake of the environment.  A more relevant approach towards sustainable cork oak landscapes may be accreditation by the Forest Stewardship Council. Certification means cork growers can supply to manufacturers traceable cork planks from forests certified to adopt landscape-sustainable practices. Part of this sustainability includes forest regeneration to prevent the landscapes from eroding.

But big plantations to increase the potential for cork stopper production are well underway. APCOR’S chairman said: “in the last ten years Spain and Portugal have planted nearly 150,000 hectares of cork forest … [so] I’m predicting we will have 15-18% more cork in 10 to 12 years from now.”  These are big plans indeed for an industry that some would write off. It’s true that the cork industry has lost market share, but an estimated 95% share of, say, a 12-14 billion stopper market in the early 1980s, to an 80% share of, say, an 18 bn stopper market today, is still somewhere between 10% and 25% growth in absolute volume terms. With a 27-year lead time for any increase in cork raw material, suddenly these plantations seem like a good idea.

That Quercus brought together eight groups from six countries (France, Germany, Italy, Portugal, Spain, UK) in a multi-discipline team should not be underestimated. It apparently took many meetings even before a title could be decided upon for the project. But since Quercus and the ensuing code of practice, the cork industry has dramatically changed the way it does things.  As APCOR’s chairman, Antonio Amorim believes the seminal moments of the last decade to be: “the change in the cork industry’s attitude towards quality and quality-related investments; the verticalisation of  the cork sectors’ leading companies, and the industry-wide adoption of GC-SPME technology.” (gas chromatography – solid phase micro-extraction).

Despite what has been achieved so far, there is still plenty more to do. Amorim said “the cork industry must avoid complacency and look for a total eradication of TCA.” The expanding boundaries of science and technology may provide help. For the moment, Hall said: “What matters is: does the industry and the consumer acknowledge that there is an improvement?”

Random, or sporadic post-bottling, oxidation is a misunderstood term. We speak of it confidently, yet not always with ful

l knowledge of its possible causes. Is random oxidation a convenient ‘cork-bashing’ tool now that those cork manufacturers who adopt best practice are finding ways to minimise TCA?  Or are there are wider issues with implications for both bottle and closure and the process that joins them together? And what about the variability of natural cork?

It may seem obvious, but “random oxidation is bottle to bottle variation” said Dean Banister, sales director of Diam, “a lot of people misunderstand and confuse oxidation with random oxidation.”  If a bottle is being tasted in isolation, without comparison to the rest of the batch, it’s impossible to say if it’s random oxidation, i.e. bottle variation, or a more widespread quality control issue.

A number of causes to consider – 1, 2 and 3: the closure, the bottle and bottling.

The closure

Everyone agrees that random oxidation can occur under any closure.

An inconsistent performance of the closure will increase the likelihood of random oxidation.  Technical closures made on an industrial scale, such as screwcaps, synthetics, technical corks such as Diam and Twintop have much greater consistency than natural cork. Jim Peck, senior research scientist with G3 Enterprises, said: “dense technical corks such as the Diam and Neutrocork have very uniform exteriors and press against the bottle bore quite tightly, reducing the possibility of  oxygen ingress no matter what the position of storage [see below].”

Natural cork is a potential culprit here; it’s a product of nature and its sealing capability is influenced by nine years of natural growing conditions.

The bottle

For driven closures, the neck bore of the bottle is key, for screwcaps, the top of the bottle.  Geoff Taylor, managing director of UK technical lab Corkwise said: “one bottle mould could give a slightly defective bore [though still within specification]. Even with a perfect closure, this could cause random oxidation.”  This is complicated by the fact that different neck bore sizes are used in different parts of the world.

Bottling

Joining closure and bottle together is a risky process for wine integrity. Bottling is, essentially, an exercise in oxygen-avoidance. The opportunities for oxygen pick up are manifold and if something goes wrong with the equipment even the best risk-management protocols can be breached.

Even with a perfect natural cork, said Taylor, “the cork may be OK, but if something as simple as the corker jaws are not set properly, the cork will be over-compressed.  The cork is blamed for random oxidation, when the jaw is at fault. Synthetics are more of a problem with over-compression because they spring back less.”  And if a crease develops along the length of the closure, then the opportunity exists for rampant and random oxidation.

Olav Aagaard, chief technology officer for Nomacorc said: “Bottling and closures are not yet integrated into winemaking. If something is wrong at bottling, people say the closure has to be guilty, but it is not always the case.” If 1 or 2 heads in a 24 head filler are badly tuned, this can lead to random oxidation down the road. And this is with any closure. 

“Differences in tooling and maintenance can create differences” said Jacques Granger, consultant to the manufacturers of Stelvin, “the shape of the filling pipe in the bottle, jogging or shocking bottles as they move between filling and capping can allow in oxygen.”   Banister added “if the labeller breaks, filled bottles wait [for the repair], then they’re sent to the capper.”   If the vacuum doesn’t pull on one bottle, to evacuate the headspace, some bottles start out with a little more oxygen.

And the rest  4, 5, 6  

Sulphur dioxide management

“No matter how good the closure is” said Banister, “if there’s not enough SO2 in use to begin with, then the wine will die.”

The first Australian Wine Research Institute (AWRI) closure trials identified oxidative characters developing in white wine at about 10mg/l free SO2.   This is a potential risk for producers operating a minimum SO2 regime.  “There’s no leeway” according to Taylor, so “if organoleptically there is no difference between 15mg and 10mg free SO2, why not bottle at 15?  We need to take more notice of SO2 because it is related to oxidation.”

Control of sulphur levels is not a random issue. But if there is no leeway, then sporadic incidences of oxidation may occur as a result of other causes.

Ascorbic acid

Ascorbic acid is often used in conjunction with SO2 to keep wines fresher and more youthful than by SO2 alone, and there have been suggestions that ascorbic acid might be implicated in random oxidation events.  Dr Geoffrey Scollary, now consulting to the wine industry, has done much research on ascorbic acid and said: “this is the critical thing. Ascorbic acid as ascorbic acid is fine and safe; as soon as it breaks downs, when more than 95% is consumed that’s when colour reactions [signifying oxidation] occur.”

But, he says: “ascorbic acid does not decay rapidly unless a large amount of oxygen is present.” Indeed, AWRI research showed wines were less oxidised if ascorbic acid was added at bottling than if it was not added. Industry consultant Richard Gibson, of Scorpex backs this up, saying “ascorbic acid is not the culprit – it cannot degrade SO2 unless it has been exposed to oxygen. And it is just not possible to get enough oxygen into the bottle at bottling to account for the extent of change that has been seen.”

Storage and transport

Incidences of driven closures moving within the neck of the bottle are well-recorded, especially as wine travels across the equator.  Mai Nygaard, Nomacorc’s business development manager said she had observed where “there’s no temperature control in the container, there is more variation on the outside boxes than in the ones in the middle of the container” which suggests such an occurrence may lead to random incidences rather than the whole container being compromised.

In a shop environment, display bottles in the window or under bright lights will have a different evolution than those kept in their cartons in the storage area.

Back to natural cork

In addition to the risk factors that cross closure type, natural cork is created by a process of nature which give it unique attributes, both positive and negative. Does its natural variability affect random oxidation events? 

Studies using Mocon Oxtran measurements ten years ago found a 1,000 fold variation in oxygen transmission rate (OTR) across a sample of natural corks. Yet other studies, using free and total SO2, and colour change measurements, show only a 2 to 3 fold variability in the OTR of natural cork.

So where is the science at now? Gibson, who was involved with the original Mocon research during his time at Southcorp said the “1,000 fold variation reflects the risk of random oxidation when upright storage with some batches of cork is used. Variation is less when laid down storage is used, but can still be considerable.” He emphasised the variation across cork batches, saying some batches are fine, but “I’ve continually said, some cork batches are worse than others.  I’ve no idea why.”    

One of the analytical issues with Mocon is that it only uses dry cork, that is, cork not in contact with wine.  At G3 Enterprises in California, Peck has developed a ‘wet’ OTR cork method for the Mocon Oxtran, which is designed to more closely resemble horizontally stored wine bottles.  He said “in an upright situation it is likely the lack of a good seal between the cork and glass that allows in oxygen through what I call micro-channels between cork and glass. As the bore of the glass bottle is decreased, a better seal is created by increased compression between the glass and the cork, sealing off these channels, lowering the OTR.  In a laid down or inverted position, wine will help seal these and also soften the cork to conform to the glass more completely, resulting in low OTR.” The study is ongoing so he doesn’t reveal the actual OTR value.

A study by Elizabeth Waters, a biochemistry research manager at the AWRI, also 10 years ago, looked at different natural corks, bottling a wine with the corks, also bottling the same wine with screwcap and bottling the wine with cork plus screwcap, one on top of the other on the same bottle. The idea being any variability under cork-stopper should not be replicated with the cork+screwcap stopper. 

The study found with some of the natural cork there was a big spread in the data for free SO2, total SO2 and colour, yet Waters said: “It is very hard to calculate an OTR variation rate from the spread of SO2 data, but with some assumptions, we can attribute a 2 to 3 fold variation in OTR to the largest spread of SO2 we saw in this study.”

In another study, using non-destructive spectrophotometry to monitor browning in white wine as a measure of oxidation, she said; “the spread of data was more like 2 fold. These values are a long way from 1,000 fold.”

Scollary’s observations of random browning also concur with the 2 to 3 fold variation. 

Miguel Cabral, heading up research and development at Amorim, the world’s biggest cork producer, said: “After the publications of Paulo Lopes et al. [at the University of Bordeaux] in the Journal of Agricultural and Food Chemistry in 2005, 2006 and 2007, it became clear that the theories defending OTR values with a 1,000 fold variation in natural cork stoppers cannot survive a scientific analysis.

“This variability obtained by Hart et al. [the Southcorp work] was probably due to a methodology error, or something else.  But one thing is clear, this information was not published in a scientific [peer reviewed] paper as Lopes’ study has been. Lopes’ data was clear: technical corks have less variability in permeability than natural corks but nothing even remotely comparable to a 1,000 fold variation.” 

He added “we are looking into reasons for the possible variability in natural cork stoppers, but its too soon to present any definitive conclusions.”

What’s clear is the science does not agree and partisan proponents are able to pick the parameter that best promotes their cause (whichever cause it is).  Speculation amongst scientists includes a rogue result in the 1,000-fold study, for example by a crease in one of the cork samples, or some unknown aspect of Mocon Oxtrans measurement that is not yet understood. Gibson emphasises he sees samples with oxidation rates that cannot be explained by oxygen ingress at bottling, and emphasises certain cork batches are worse than others for reasons we don’t yet know.

It’s clear the science is at odds on this issue, which is not necessarily unusual, and industry can draw no definitive conclusion until the science catches up to explain experience. It’s only in recent years that miniscule oxygen ingress has been widely accepted as a normal part of bottle age.

The reality is there’s not been much work done looking at the OTR variability of natural cork, apart from the studies mentioned.  Another reality, perhaps related to the first, is the measurement of dissolved oxygen in wine is still a major technical and analytical challenge, whatever the methods used. But science is on the cusp of a new frontier of oxygen measurement and, therefore, management. This will undoubtedly help our understanding of non-random and random oxidation events.  Peck even suggests emphasis might shift to the bottle, saying “I suspect that bottle bore may have been the culprit as much or more than the cork. We now do much of our OTR testing in precision bore glass sleeves to eliminate problems with bottle bore variation.” 

We await results from Peck’s ‘wet’ Mocon measurements. And at the AWRI, Waters is beginning research using two new methods. Oxysense uses “oxydots, a fluorescent method, using scanning technology to measure oxygen through bottles” and the other new method has been developed at the AWRI, which uses a specific oxygen trap.   

What is clear is that random oxidation can occur across closure types. Natural cork is more variable than industrially produced closures. More than this we cannot really say until science provides industry with consistent, and commercially-useful, information. The spotlight, or maybe the oxydot, is on.