According to a Sainsbury's press release, the retailer "has worked with the cork manufacturer Sabaté for two years to develop natural cork based closures which go through a process of carbon dioxide extraction to 'clean' them [i.e., to levels undetectable by current state-of-the-art equipment] of TCA, protecting the wine from cork taint."
This is achieved by treating the cork with supercritical CO2 to extract TCA - or 2,4,6-trichloroanisole to give it its full name - the naturally occurring compound which is responsible for the mouldy, musty taste and odour of corked wine, and has been developed by Sabaté to help winemakers tackle the problem of combating wine taint at the same time as meeting consumer demand for cork, rather than synthetic, closures.
The Australian Wine Research Institute (AWRI) recently tested three models, and according to Sabaté USA president Eric Mercier, the results were impressive. Sabaté's new closures were tested along with a range of other closures and closure types. A screw cap was used as the control. The three Sabaté closures tested were all technical closures manufactured with cork granules treated with the supercritical CO2 extraction process the company calls 'Diamond.'
This is good news for the wine cork industry. There is increasing competition within the wine closures market, and Sainsbury's adoption of the new cork concept suggests that the material now has a technological edge - as well as traditional consumer preference for cork - to back the product up against new synthetic alternatives.
Up until now, synthetic stoppers have been seen as the most obvious way of addressing the problem of wine taint. But while this is one way of significantly reducing the problem (although evidence suggests that TCA from sources other than cork - such as wooden barrels or even the drainage system of the winery where its made - can still contaminate wine in screw cap bottles) consumer acceptance of such closures remains mixed.
Writing in FoodandDrinkEurope.com for example, Chris Jones points out that research carried out recently in the UK shows that while British consumers are the most accepting of a wide variety of closures, most still prefer to hear the pop of a natural cork when they open a bottle of wine. He cites specialist wine industry market research group Wine Intelligence findings that show that UK consumers clearly ranked cork as their favourite, with synthetic corks in second place and screw-caps a distant third, with nearly 60 per cent negative response.
"The distinctive 'pop' of a wine cork is still a key element of the wine drinking ritual, say consumers, and it is not one they are keen to give up," said Wine Intelligence's Richard Halstead. "Some 99 per cent of respondents to the survey said they were positive or neutral about cork. By contrast, nearly six in 10 respondents said they did not like buying wine with screw caps."
Halstead continued: "Ordinary consumers are not yet willing to abandon a key element of the wine drinking ritual, despite evidence pointing to the better sealing properties of screw caps. There is a danger here that retailers and wine producers will move too fast to embrace the new technology and in doing so alienate key segments of consumers."
However, the concern for the pro-cork lobby is that the move towards synthetic closures is gaining marketing momentum. For example, Halstead said that many New Zealand Sauvignon Blancs now came with screw caps because they were seen as best fitting the 'fresh' image of the wines themselves, less staid than their European equivalents.
The survey results suggest that this is a marketing policy which is working well: just over half of New Zealand wine drinkers thought that a screw cap on a bottle represented good value.
But in the end it will be cost which plays the most important role, it seems. Halstead said that a new survey from Wine Intelligence, due to be published soon, showed that synthetic closures were already the stopper of choice among the UK's leading wine buyers, and suggested that this, rather than consumer demand, would drive the market in the future.
Once large quantities of wineries orders are for wine bottles with synthetic stoppers, the cost of running separate lines for cork and alternative closures could become a more pressing problem, especially for smaller producers, effectively obliging them to switch to 100 per cent synthetic closures or risk losing a large part of their custom.
The number of wine bottles affected by cork taint is difficult to assess, with figures put at anywhere between 1 per cent (a figure cited by the cork industry) and 15 per cent (a more anecdotal figure based on winemakers' own perceptions), but no matter how high the exact figure is, the problem is one which plagues wine marketers the world over.
Jones says that the vast majority of the global wine-drinking public are enthusiastic amateurs or absolute beginners - in other words, they are highly unlikely to realise that corked wine is a widespread problem which can affect any product or brand. They are in fact much more likely to link it directly to the specific wine affected by the taint, making the chances of them buying that wine again extremely remote, with obvious implications for the winemaker.