Define 'cork taint'.

Cork taint refers to a wine defect that occurs when a wine bottle is contaminated with trichloroanisol (TCA). This contamination typically happens when corks are made from treated cork bark, and the TCA forms as a result of the interaction between certain chlorophenol compounds and the natural elements present in the cork. The presence of TCA in wine leads to a musty, moldy odor that can obscure the wine's true character and aromatics.

This defect can vary in intensity from very faint to severely overpowering, and it can spoil the drinking experience by making the wine seem dull and lifeless. Understanding cork taint is critical for sommeliers and wine professionals, as it directly impacts the quality and enjoyment of the wine being served.

The other options do not accurately reflect the definition of cork taint; one suggests it's a pleasant aroma, which contradicts the nature of taint; another describes a method of sealing bottles, which relates to cork but not to taint itself; and the last option mistakenly identifies cork taint as a type of wine barrel. Thus, recognizing cork taint is essential for maintaining high-quality wine service.