Cork and TCA: Fighting Against Tainted Wine

You’ve planned a celebration to commemorate a birthday, anniversary or the acquisition of a new job. As the family gathers around the dinner table, you open the special bottle of wine purchased for the occasion. When the wine is poured, you notice that it smells like damp cardboard, rather than the glorious aromas of blackberries and cherries you were expecting. The wine is ruined.

If you think that situation is unfortunate, try this: You’ve pulled the last bottle of 1990 Chateau Latour from your cellar. You bought the wine as a future before release, paying slightly more than $100 per bottle for a wine worth about $1500 today. You open the bottle, carefully decant it, and realize that it is undrinkable.

In both cases, your wine was likely affected by a bacteria called TCA, or 2,4,6-trichloroanisole, which accounts for that musty smell and robs the wine of both aroma and flavor. In some cases it attaches to the cork during the aging process, although no one is exactly sure how. There are many theories about where it comes from and how it spreads. In the worst-case scenario, TCA can infect a cellar and ruin an entire batch of wine.

Most consumers who encounter a “corked” bottle of wine can spot it immediately, but those are only the full-blown examples. There are many bottles devoid of aroma or flavor, and we tend to make excuses for them (the wine needs time to aerate, the wine is going through a dumb stage, etc.). More than likely, these bottles are suffering from the early stages of TCA contamination. The best estimate on bottles with TCA contamination is that they comprise 5-6% of the wine sealed with corks.

This would be unacceptable with any other type of consumer product---if 5% of milk were ruined by bacterial contamination, you can be certain something would be done about it. One of the worst aspects of TCA is that many beginning wine drinkers are unsure whether or not the wine is bad; while they realize it may not smell or taste exactly right, they also have no precise idea what it would be like in good condition. If the wine is a current vintage and/or recent purchase, you can return the bottle to the retailer for credit. Our friend with the 1990 Chateau Latour would not be quite as lucky (“Excuse me, but I bought this bottle here 21 years ago, and there seems to be something wrong with it…”).

The first step in addressing this problem was the development of synthetic, or plastic corks. While free from TCA contamination, these had several drawbacks. They tended to offer a much tighter seal than real cork, and were difficult (sometimes impossible) to remove from the bottle. Because of the tighter seal, they also did not allow the very gradual inflow of oxygen that real cork made possible, and were thus unsuited for long-term aging.

The Stevlin, or screwcap closure, first made its mass-market appearance on bottles of Sauvignon Blanc from New Zealand. There was initial resistance to them in the United States, since wine with screwcaps was historically a low-grade product consumed by alcoholics. Gradually, consumers realized that a screwcap closure delivered a wine that was brighter, fresher, and free of contamination. The issue of how wine ages in these bottles is still a mystery, but they have been adopted by wineries all over the world, and today accounts for nearly 20% of bottled wine. It can be argued that if you plan on drinking a wine within 18 months of release, as most of us do, the only thing you are adding with a cork is a 5% chance that the wine will be undrinkable.

Other types of alternative closures are Vino-Seal (a glass stopper), Zork (which seals like a screwcap but pops like a cork), and the old-fashioned crown cap. This latter solution is frequently applied to local wines desgined to be consumed young, and which will not be exported beyond their immediate region.

Don’t think that the Portuguese cork producers are thrilled by the popularity of alternative closures. Cork is a huge industry in that country, and the growers have lost nearly one-fourth of their income in recent years. On a visit to Portugal last year, I was told by several people that it would be “unpatriotic” of them to purchase a bottle of wine with a screwcap (not that they could find one there in any case).

The extent of Portuguese consternation over alternative closures was revealed in a pair of recent ads produced by an organization called 100% Cork, which is sponsored by the Portuguese Cork Association and the Cork Quality Council. The first one depicted an upwardly mobile female executive bringing a bottle of wine to an office party. When her colleagues discover that the bottle has a screwcap closure she is disgraced and shunned, her career ruined. In the second, a young man is opening a bottle of wine while attempting to seduce a lady friend. The amorous woman is completely turned off when she realizes the bottle has an artificial cork. When he tries again with a bottle sealed by a real cork, she literally throws herself at him.

A study conducted by Lab Excell and published in the Journal of Agriculture and Food Chemistry suggested that French oak barrels might actually be the culprit in corked wine. In fact, a chemical precursor to TCA is also an agent used in processing wood. Even so, the French coopers and barrel manufacturers went ballistic over this, accusing Lab Excell of having a secret profit motive (they’ve developed a procedure to check barrels for TCA before they leave the cooperage).

If you encounter a bottle of wine ruined by TCA, what’s your best course of action? If the contamination is full-blown and it’s feasible to return it, do so. If not, you can try soaking some plastic wrap in the wine. For some reason, the TCA is attracted to the polyethylene in the plastic, and this actually seems to help. It also makes an interesting topic of conversation at dinner parties.

What are you personal experiences with “corked” wine? Have you encountered them often, and if so, what do you usually do about it?