Due to improper production, handling or storage, there are a fair amount of things that can go wrong with wine--most of which should be cause to return a wine if ordering in a restaurant. Some wine merchants will also take back a flawed wine, though I suspect only for their best customers.

How often a wine is flawed turns out to be a controversial questions. Some people feel that 1 out of every 12 wines they consume is flawed. Personally, I don't find anywhere near that many wines to be a problem (but then I don't have the wherewithall to consume a lot of really old wine).

A good number of people, when faced with a bottle that doesn't seem right (or is just plain awful) will say that it is "corked." They have come to use the term as a catch-all for all flaws. So just what is a corked wine?

Corked Wine

To me corked wine has the flavor of wet, musty cardboard. Once you have really tasted a corked wine, you'll know what it is--it is not subtle. It is caused by trichloranisol [(TCA) 2,4,6], a compound released by molds that can infest the bark from which corks are made. One theory: you can't get TCA without chlorine, which is used to bleach corks (for aesthetic reasons). If corks aren't properly rinsed and dried this problem can occur.

If you haven't been "lucky" enough to experience a corked wine (at least for educational purposes), apparently you can buy the odor of the stuff from enterprising entrepreneurs. One advertised business is: The Wine Trader, attn: "Corky," P.O. Box 1598, Carson City, Nevada 89702.

Other Flaws

While some people attribute all flawed bottles to being corked, there are a number of other things that can go wrong. A non-exhaustive list follows.

  • Brettanomeyces(Brett). Earthy and/or manure type smells caused by the Brettanomeyces strain of yeast. Liked by some (for example particular French wines), disliked by many California vintners. In small amounts, can add "character" to a wine. Too much, and forget it.
  • Dekkera. Another wild-yeast caused flavor of fresh dirt or cement. Liked by some (for example in some Bordeaux, Burgundy, Rhone and Italian red wines), disliked by many California vintners. Dekkera can also come from contaminated equipment and barrels.
  • Madeirized. Wine subjected to oxygen or heat through poor storage which ends up tasting like Madeira or Sherry. No fruit flavor left. Off-color.
  • Mercaptan. Smells of garlic or onion or even of skunk. I'm told that this is much of the cause of the "foxy" flavor produced by grapes native to North America. It is said that the term "foxy" came about because there wines were often made from the Fox grape, where the flavor was first seen.
  • Sulfur. Burnt match smell caused by too much sulfur dioxide (used in the winemaking process) and rotten egg smells caused by hydrogen sulfide from bacterial contamination. Depending on what it is, it might go away if you air the wine for a while.
  • Volatile Acidity. Smells of vinegar. May go away if you air the wine for a while.

There are long lists of flaws and descriptions in How to Test and Improve Your Wine Judging Ability (see BOOKS section), and Elements of Wine Tasting (American Wine Society Manual #11).

Something that probably isn't a flaw are tiny glass like crystals on the bottom of the cork (or sometimes in the wine). Assuming they really aren't glass from the winery, they probably the result of tartaric acid in the form of potassium bitartrate (cream of tartar). I'm told that this is tasteless and harmless. I've seem them and they haven't hurt me!

A final note about flawed wines. If you are on good terms with the store or winery from whom you purchased the wine, they will often replace a bottle which is flawed. No harm in trying!