Cork taint
Wet cardboard, damp basement. At low levels it does not smell of anything: it just strips the fruit out of the wine.
What causes it
TCA, formed when chlorine compounds meet mould, usually in cork but sometimes in the cellar itself.
Detection threshold
A few nanograms per litre; among the lowest sensory thresholds known.
There is no fix
None for the bottle. If several bottles are affected, suspect the cellar rather than the cork.
How to prevent it
Never use chlorine-based sanitiser anywhere near a winery.
Others in chemical and taint
Excess sulphur dioxide
A sharp prickle at the back of the nose, like a struck match, and a stinging sensation rather than an aroma.
Ethyl acetate
Nail polish remover, pear drops, model glue.
Smoke taint
Ashtray, burnt rubber, and a long drying finish that arrives after swallowing rather than on the nose.
Metallic taint
Blood, tin, a hard metallic finish, and often a haze that appears weeks later.