Corks Without Corkiness

In the first major use of a closure other than natural corks for fine wine, St. Francis Winery in Sonoma County has begun using synthetic corks. The switch was aimed at eliminating the corky aroma that has plagued many wineries in the last few years. Wineries report between 2% and 4% of all bottles of wine are “corked.” The undesirable aroma has been identified as a trace amount of a chemical called TCA-2-4-6, which appears to be a result of sterilizing natural corks with bleach.

St. Francis winemaker Tom Mackey conducted two years of tests on the synthetic cork material (Cellukork) for such problems as corkiness, leaks, pressure and flavor change. He says he found the Cellukork better in all respects.

Natural corks cost between 18 and 35 cents each, while Cellukork costs only 10 or 11 cents, but Mackey says cost was not a major consideration. “The primary reason we went to this was corkiness,” says Mackey. “Since we started using it, we haven’t had one corked bottle. In fact, the wines I bottled last summer are almost too fresh. The Cellukork slowed down the bottle aging process, which makes the wine more durable in adverse conditions.”

Mackey says the tighter seal may permit him to lower even further his use of sulfur dioxide in bottling: “There will be less air getting in, so we may not need as much sulfur as a protectant.”