When we say that a wine "tastes like cork" we are referring to a defect in the wine known as "cork taint". This defect is caused by the presence of a chemical substance called trichloroanisole (TCA) inside the cork or other materials in contact with the wine, such as labels or wooden cases.
Trichloroanisole is formed when chlorine, present for example in water or in disinfectant agents used in the wood industry, reacts with natural substances present in cork bark or other materials. This chemical reaction can produce volatile compounds such as TCA, which have a distinctive and very recognizable odor, often described as "mold", "wet cardboard" or "corky".
When a wine is contaminated with trichloroanisole, its aroma and flavor can be seriously compromised, making the wine unpleasant to drink. Even small amounts of TCA can have a significant impact on the sensory profile of wine.
The presence of this defect can be detected through smell before even tasting the wine. Therefore, if you notice a strong cork smell coming from the bottle or glass, it is likely that the wine is affected by this problem. Cork taste is one of the most common defects in wines, but modern production practices are trying to reduce its incidence through more rigorous quality controls and the use of materials with low risk of contamination.