Sun, Sep 30, 2007 - Page 9 News List

Screw caps divide winemakers

Given the maddeningly random problem of wines contaminated by cork taint, it's easy for consumers to wonder why the entire industry has not moved to screw caps


Grant Burge, an Australian winemaker, is no fan of screw caps. This puts him in something of a minority position in Australia and New Zealand, where the vast majority of wines that sell for US$25 and less have forsaken corks.

He has done that for his less expensive wines, he said, mostly because restaurants told him they would not sell his wines otherwise. But he doesn't have to like it.

"I'm actually a traditional cork person," he said over lunch recently in New York. "I didn't really want to go to screw caps, but I'm not blind, either. My top six red wines, I refuse to go to screw caps at this time."

With that, he applied his corkscrew to a bottle of 2004 Grant Burge Filsell, an intense, polished Barossa Valley shiraz that sells for about US$35. He poured a glass, took a sip and grimaced. It was corked.

Given the maddeningly random problem of wines contaminated by cork taint, it's easy for consumers to wonder why the entire industry has not moved to screw caps. Sure, some people will always prefer corks for esthetic reasons and because of tradition. The ceremonial flair of uncorking a bottle has yet to find its counterpart in an unscrewing. And while it's not yet clear how age-worthy wines will evolve under screw caps, the question remains: Why would anybody want to risk corked wines?

Screw caps are effective antidotes to cork taint, which is caused by a compound called 2,4,6-trichloroanisole, or TCA, a result of fungi that occurs naturally in the cork tree. Corked wines take on a moldy, musty aroma resembling wet cardboard. Sometimes the aroma is obvious to all, while other times only the most sensitive noses can detect it. Either way, it is an irreversible problem that dooms what many experts estimate to be about 5 percent of wines that use cork closures.

But screw caps, it turns out, have their own issue. It can be summed up by this forbiddingly opaque bit of wine jargon: reduction. Please bear with me as I try to explain what that means.

Winemakers battle endlessly with air. In general, they want to protect their wine from too much exposure to air in order to prevent oxidation. That is why wine bottles are filled nearly to the brim and then sealed.

Yet a little bit of air can be a good thing. A chardonnay, for example, can be protected from air by covering it with inert gas and aging it briefly in steel tanks. When bottled, it will mostly likely be a straightforward wine, juicy, fruity and crisp. But chardonnay aged in oak barrels will be exposed to the minute amount of air that penetrates the wood, which can add pleasing elements of complexity. It's all a matter of the winemaker's goals and the quality of the grapes.

Depriving a wine completely of air can produce the opposite of oxidation, reduction. Broadly speaking, reduction is a kind of catchall term for the bad things that can happen in what scientists call anaerobic conditions. Those bad things involve sulfur chemistry and can ultimately include aromas of burned rubber, cabbage and rotten eggs.

Yes, screw caps, the good guys in the battle against corked wines, have been implicated in reduction problems.

"With the widespread use of screw caps," Jamie Goode wrote recently in Wines & Vines, a trade publication, "some technical issues have emerged, surrounding the post-bottling sulfur chemistry, known more commonly as `reduction' in the trade."

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