Thursday, April 9, 2009

Corked wine--what to do about it?

In his blog today, the San Francisco Chronicle's Wine Editor, Jon Bonné, investigates a way to remedy corked wine at home. Before we explain cork taint, the remedy, and how it works, we must stress this:

If you have a corked wine, take it back where you bought it! You will get the wine replaced or your purchase price refunded.

If you bought the wine at a winery, they will be very happy to take it back. They do not want any consumers to think their wines are bad because of a corked bottle.

If you bought the wine at a wine store, they too will take it back. It will not cost them anything, as they will in turn give it back to the distributor for a credit, and the distributor will return it to the winery (or at least report the incident to the winery).

If you bought the wine at a supermarket, returning it might be a little harder. You may need to ask around to find a manager or whomever is in charge of the wine section, but once you have done so you should have no trouble making the return.

Inconvenient, perhaps, but not as bad as dumping a ruined wine down the drain or, worse yet, drinking it.

So, we do recommend attempting to resurrect a corked wine, but only if you are unable to return the wine.

What is a corked wine? There are many ways a wine can be off. Cork taint is among the most insidious. The taint is caused by a compound called trichloroanisole, or TCA. (Geek aside: Less frequently, the chlorine can be replaced by other halides, so trihaloanisole is a generic term for all the compounds that affect the wine in a similar way.) TCA is produced by molds as a defense against toxic (to them) chlorophenols.

The human nose is incredibly sensitive to TCA. Most people can identify TCA in concentrations as low as 4 parts per billion (4 nanograms per liter). TCA smells, by the way, like an extremely unpleasant musty attic.

What's more scary for wine producers is that below the recognition level, TCA still has effects: it reduces all the aromas in the wine, making it seem bland and uninteresting. Believe us, winemakers would much rather have a consumer recognize a wine as corked than have them think that the wine is flawless but boring.

TCA also has lingering effects. It is persistent. So if you smell a corked wine, and then smell another wine to compare, you will likely think that both wines are affected. Give your nose a good break (20 seconds or so) before making the comparison.

Bonné describes the home remedy well, but here is a summary. Crumple up a bunch of plastic wrap (to maximize surface area), and place it in a vessel, such as a decanter or even a bowl that is large enough to hold what remains of your wine. Pour the wine over it and let it sit for ~20 minutes. If you have two decanters or bowls, you can go back and forth a few times.

Discard the plastic wrap and drink the wine, which will be much better. Bonné recommends keeping a sample of the untreated wine as a comparison, but remember the warning about the persistence of TCA.

Why does it work? TCA has a greater affinity for the plastic than it does for the wine. The geeky explanation is that TCA is non-polar, as is plastic. Wine is mostly water, which is about as polar as you can get, with alcohol, which is only weakly non-polar. So TCA is attracted to the alcohol in the wine, but nowhere near as much as it is attracted to the plastic.

Do note that many aroma compounds are non-polar and will also leave the wine in favor of the plastic. This treatment will improve a corked wine a great deal, but will not make it the same as an uncorked, untreated bottle of the same wine.

Good luck, and remember--take those corked wines back where they came from!
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