Smoke taint
Ashtray, burnt rubber, and a long drying finish that arrives after swallowing rather than on the nose.
What causes it
Volatile phenols absorbed by the grapes from wildfire smoke, then released from their bound forms during and after fermentation.
Detection threshold
Very low, and it gets worse with time in bottle as bound precursors hydrolyse.
What you can do
Reverse osmosis with resin treatment works commercially and is out of reach at home. Short skin contact and early pressing limit what is extracted.
How to prevent it
Test the fruit before buying it in a fire year, and consider making a rose or a white from red grapes, since most of it lives in the skins.
Others in chemical and taint
Cork taint
Wet cardboard, damp basement. At low levels it does not smell of anything: it just strips the fruit out of the wine.
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.
Metallic taint
Blood, tin, a hard metallic finish, and often a haze that appears weeks later.