Common wine faults: cork, oxidation, brett

Wine faults are deviations that diminish a wine's intended character. The most common fault is cork taint (TCA – 2,4,6-trichloroanisole): a musty, cardboard or cellar-like smell that mutes fruit and makes the wine flat. TCA is formed by mould fungi in corks and wood. Oxidation occurs when wine is exposed to too much oxygen: white wines darken and develop nutty, madeira-like notes; red wines lose fruit and colour. Brett (Brettanomyces) gives stable, leather and plaster notes. Beyond these, volatile acidity (vinegar, ethyl acetate), reduced sulphur compounds (egg, onion) and excess SO₂ (pungent sulphur) also occur. Being able to identify faults is as important as identifying quality – it protects you as a consumer and educates your senses.