Cooked or Corked

Despite modern winemaking, or storage and shipping technology, nearly 5% of all wines arrive at the table with less than desired quality. Here are a few tips on how to spot a poor quality wine.


A good wine must have a satisfactory cork. Even today with high-technology plastics, many bottles are still stoppered with an old-fashioned cork. A cork is a product of the bark of specially selected Mediterranean trees. It has many highly desirable and hard to duplicate attributes such as it is lightweight, resistant to disease and airflow, flexible and attractive.

Unfortunately cork is a natural product and is susceptible to attack by microorganisms. Certain types of fungus, present anywhere that wine is stored can infiltrate the cork which results in a compound called TCA (1, 2, 4-trichloroanisol).

TCA and other factors produce appalling odors and tastes in wine, similar to wet cardboard, mushrooms, mold and even dirty socks. Even when the odor is mild the taste may be bitter and lack fruitiness.


Moving wine from the vineyard to the table involves trips that can be as far as thousands of miles. This makes it surprising that only 5% of wine is partially spoiled due to excessive temperatures.

High temperatures can cause wine to expand slightly increasing the pressure inside the corked bottle. The pressure can cause the cork to be pushed up slightly. When the wine cools air seepage can occur.

If the temperature becomes too high the wine can be cooked within the bottle. If this has happened it will result in a taste more of stewed prunes than fresh berries. To spot this problem look for corks that sit above the lip of the bottle, or levels of liquid near to the base of the neck.


Storage environments subject to excessive heat, cold or incorrect humidity levels, can cause the cork to shrink or crack. When this happens infiltration of unwanted amounts of air into the bottle occurs, causing oxidation. Oxidation is simply oxygen combining with a variety of the wine components and altering them.

Air taken in small amounts over a number of years may be desirable to ensure proper aging. However, well before producing vinegar it is possible to spoil a wine by allowing too much air to reach the wine. Wine that has become fruitless and resembles old Madeira (deliberately produced in open air vats) is almost certainly oxidized.

Sulphur and Sediments

Sulphur is a common preservative in winemaking which is used to help stabilize the wine. However in excessive concentrations it produces an undesirable aroma and flavor. The characteristic smell or taste of mothballs or burnt matches makes it quite easy to spot.

A certain amount of sediment in wine is acceptable and normal. Ports, older wines and even whites, can often accumulate material and if properly poured or decanted are fine. Tartrate crystals will also naturally form in some wines, especially if it is chilled before shipping and storage. These will not harm the wine but avoid pouring and tasting them.


Occasionally it is possible for dormant yeasts to remain in the wine and ferment the wine during years of shipping and storage. This is a very rare occurrence. Champagne, is deliberately refermented in the bottle however, for non-sparkling wines this is undesirable but easily spotted.

Manufacturing techniques of bottling, shipping and storing wine continue to improve and the odds of encountering one of these conditions is quite rare. Most of the time a wine that doesn't suit the palate, is simply not for the person tasting it.

Swirl the wine gently, sniff and taste.

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