My Money's on Cork (September 21, 2007)
For the last twenty years Ontario wine writers have tasted the wines listed by Vintages' stores about three weeks before their release. The bottles from all over the world are lined up in the LCBO lab on a long U-shaped table. Whenever one of us comes across a corked wine (a wine affected by cork taint), we put an upturned glass on the neck of the bottle as a warning to our colleagues.
Last week Vintages' staff put out 107 wines for sampling. When we had finished our tasting there was only one bottle wearing a glass. This happy circumstance has nothing to do with the number of wines now under screwcap, but everything to do with the cork producers' belated attempts to deal with the problem of infected corks that taint wine.
The taint is caused by mold in cork bark, which, if it is not neutralized, can bond with chlorine that was used to bleach and clean the corks. When in contact with wine this combination can create a compound called trichloroanisole (TCA).
TCA makes wine smell like a swampy basement but in lesser amounts is almost undetectable on the nose. Yet even in undetectable amounts it flattens out the flavours and consumers wonder why their favourite wine doesn't taste as good as it did last week. (TCA, incidentally, is not exclusively a cork problem. It can also come from contamination in the cellar: in 2003 Gallo admitted it had TCA in its Sonoma facility caused by the use of chlorine to clean tanks and hoses.)
All of us have been served corked wine at some time or other and the cork industry's inability or unwillingness to come to terms with the problem sent winemakers in search of alternative closures. First there were plastic "corks" and then glass stoppers and the most successful closure to date, the screwcap. Each claimed it was the answer to corked wines. But the perfect closure has yet to be designed.
Independent studies of cork, plastic and aluminum closures by research institutes in Australia, Belgium, the Netherlands and South Africa have shown that each method has its own problems. Cork is subject to TCA; plastic does not provide a totally hermetic seal, which means that wines can oxidize over time (let alone the difficulty in removing and recorking); and screwcaps, because they are impermeable, create a build-up of sulphur dioxide that gives the wine a rubbery, struck flint character. One New Zealand journalist infuriated his country's wine industry by suggesting that the plastic liners in screwcaps might leach endocrine disruptors into wine, which can cause breast and prostate cancer.
In this era of environmental preoccupation my money is on cork as the once and future closure for wine bottles. Unlike plastic and aluminum, cork is a renewable resource. A cork tree can be harvested every nine years. Cork is biodegradable, while plastic and aluminum are not. The environmental impact of screwcap production has been calculated to produce nine times the amount of carbon dioxide that it takes to produce the same number of corks. And cork trees absorb carbon dioxide. Add to this an apocalyptic warning from the World Wildlife Fund in May 2006: "Unless the commercial value of cork stoppers is maintained there is a risk that the Western Mediterranean cork oak landscapes will face an economic crisis
an intensification of forest fires, a loss of irreplaceable biodiversity and an accelerated desertification process within less than 10 years, according to the worst case scenarios."
Amorim, the world's largest cork producer, which sells three billion corks a year, has spearheaded Portugal's drive to rehabilitate cork in the consciousness of both consumers and winemakers. They have instituted selection, storage, cleaning and quality control protocols that will reduced the incidence of TCA to a minimum. Their methods include storing the cut bark not on forest floors, as was the custom, but on concrete areas outside their factory as large as seven football fields; boiling the cork bark and then subjecting it to high pressure steam instead of using chlorine; and submitting the final product to chemical analysis.
There is no argument from winemakers that when cork works it's the best closure for wine. And for consumers, what would you rather have? A piece of petroleum product in your bottle or a natural cork? And when it comes to tableside service, what would you rather sniff, a cork or a piece of tin?