Adam Lechmere, editor of, recently reported that the cork industry has secured the endorsement of Prince Charles for a new campaign called ‘I Love Natural Cork’, Vine Talk: Campaign promotes wine corks over screwcaps, Reuters, 7 September 2010.

The cork industry’s public relations material is designed to appeal to our sense of tradition and ‘green’ conscience: “Natural cork in your wine bottle does more than just preserve and improve the quality and character of your wine. It preserves a centuries-long way of life in the rural communities of the Mediterranean cork oak forests, its incredible wildlife as well as the planet by absorbing CO2.”

The decline in cork’s popularity as the preferred wine stopper is certainly a serious cause of concern for the cork industry, and especially for Portugal, which makes 85 per cent of the natural closures – a figure that accounts for approximately 3 per cent of its GDP. As Lechmere notes, 10 years ago 95 per cent of bottles had cork closures. Last year, natural cork accounted for 69 per cent of the 18 billion wine closures sold.

But leaving aside for the moment the merits of the preserving centuries of tradition and stopping global warming, is cork still the best closure for preserving and improving the quality of wine?

Wine connoisseurs are now starting to sample bottles with screwcap closures that have been cellared for almost a decade.

Campbell Mattinson, wine critic and editor of The Wine Front, made the following observations in his January 24, 2008 review of a Howard Park Cabernet Merlot 2001:  “It’s hardly ‘news’ but I was delighted to enjoy a bottle of 2001 Howard Park Cabernet Merlot last week – sealed under screwcap. This was my favourite red wine of the 2001 West Australian vintage and as a (nearly) seven year old it’s in the steady process of fulfilling every inch of its early promise. What delighted me as much as the wine though was its level of development; it was pretty much exactly as you would expect to see from a well-performing cork-sealed wine. Proponents of screwcap seals have long argued that, contrary to some popular opinion, screwcaps are “not a cryogenic chamber”, and wines do still develop well, and at an essentially ‘normal’ rate, under screwcap. This 2001 Howard park Cabernet Merlot, under screwcap, will enter its drinking peak in three or four year’s time, and will sit happily in that peak for a decade or more.”

The problem of cork taint is the main reason why wine producers have been attracted to alternatives. Lechmere estimates that the natural stopper has a failure rate of between 1 to 6 per cent, which he and many others regard as unacceptably high. As noted Australian wine critic James Halliday points out in his video post, Cork vs screwcap debate 23 May 2010 YouTube, sporadic oxidation is another problem associated with cork, because it is more likely than metal to deteriorate over time.

Due to investment in technology and research into the causes of trichloranisole or TCA, the mould-like compound which causes cork taint, rates of corked wines are falling. Lechmere observes that retail heavyweights like Sainsbury’s in the UK are starting to back cork again.

But while the verdict on cork closures is still out, many influential wine industry figures believe that screwcap is the best solution for the vast majority of wines. In fact James Halliday argues that the wine industry should be discouraged from using a closure which has two major defects: TCA and sporadic oxidation. He goes so far as to argue that “Winemakers in Australia (and I’ll wager the United Kingdom and the United States) are guilty of offenses under the Trade Practices Act if they knowingly sell a defective product, or a product which is not in fact suited to the purposes for which it is sold.” (Screwcaps and the Iberian Lynx, 28 July 2010, Australian Wine Companion)

Certainly, the cork woodlands in Spain and Portugal are worth preserving. For centuries they have provided shelter for many species of birds. Cork farmers carefully nurture and sustain their trees because it takes twenty-five years for the bark to be good enough to harvest, and the bark can only stripped every nine years. But as Lechmere and others point out, cork can always be used for other purposes; cork tiles, for example, are now back in vogue!