intner Views – January '07

 Wine Closures

   Whether it’s natural or synthetic cork, technical cork or a screwcap, the job is the same:  1. Keep the wine in the bottle; 2. Do so without damaging the contents.  Cork has been the traditional choice for centuries.  However, in the last 15 years, increasing awareness of a problem called cork taint has caused industry suppliers to offer alternatives to natural cork.  Included are synthetic corks of various kinds, technical corks, and screwcaps.  Technical corks are made of cork material that has been ground up and glued back together, like particle board.  Synthetic corks are made of some sort of plastic or other manmade material.  They come in various colors and act and feel similar to a real cork.  Screwcaps seem to be the latest and strongest challenger to natural cork.  These closures add no flavor, seal the bottle perfectly and don’t require a corkscrew.

   However, there is a perception in the marketplace that associates screwcaps with low quality wine.  Some wineries are gambling that perception is changing.  There’s no doubt that screwcaps perform well, and have gained a lot of ground on the other alternatives to natural cork.  But among wine producers in the U.S., natural corks are still the most popular closure.  Natural corks may allow very small amounts of oxygen into the bottle, which is said to be a good thing for wines that are intended to age for a period of years.  Wines that are aged without any access to oxygen may become “reduced”, a condition that gives the wine off aromas, sometimes like rubber or rotten eggs.

   Cork taint is the biggest concern with natural corks.  Cork taint gives the wine a musty, dank or moldy character, and is said to strip the wine of its fruit.  It is caused by a chemical called 2,4,6- trichloranisol, or TCA for short.  After  the wine comes in contact with the affected cork, the TCA transfers to the wine.  Some experts have stated that as much as 10% of naturally corked bottles may exhibit cork taint.  The big stink is that we humans can detect TCA down to around 5 parts per trillion.  That’s a VERY small amount.  Restaurants are particularly wary of cork taint because knowledgeable customers may rightfully reject a “corked” bottle of wine.

   Certain cork suppliers have responded to this problem by screening corks for TCA using expensive gas chromatography.  If the corks test out above a certain level, they are rejected.  Preventing cork taint may be as simple as buying good corks from a reputable supplier.  More recently, suppliers have developed ways of actually extracting and eliminating TCA from the corks.  This ancient closure isn’t quite obsolete, and won’t be for some time.

   One of the beauties of wine is the cork.  It takes a special tool and a bit of skill to extract, and the ritual is part of the intrigue and romance wine.  Though it’s not a perfect solution, it does work, and it adds an element of the ancient – a tie to the past.  Provided we can manage the TCA problem, natural corks will likely continue to play a significant role in protecting our wine.  Don’t trash your corkscrew yet.

This article appeared in the January 24, 2007 edition of the Grand Junction Free Press.

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