Rescues · TO SMOKE
Bitter, ashtray flavour.
Why it happens
Dirty smoke from a smouldering fire, or wood that was damp or resinous. Softwoods are generally unsuitable for this reason.
Recovering it
Under-smoked food can be smoked further, though returns diminish sharply after the first hours. Over-smoked or bitter food cannot be fixed — trimming the surface removes some of it, since smoke is a surface phenomenon, but the flavour has usually carried inward. The prevention is a clean, well-aired fire and hardwood: almost every smoke failure is a fire failure rather than a food one.
The mechanism
Wood smoke is not one thing. As wood breaks down it releases phenols, which give the characteristic smoky aroma and are mildly antimicrobial; carbonyls, which contribute colour and help form the bark; and organic acids, which lower surface pH. It also releases creosote and unburnt particulate when combustion is poor — and that is the difference between good smoke and bad. A clean fire with enough air produces smoke that is thin and faintly blue; a starved, smouldering one produces thick white or grey smoke loaded with the compounds that taste acrid. Smoke deposits only on surfaces, and adheres far better to a moist, slightly tacky surface than a dry or wet one, which is why a pellicle — formed by air-drying uncovered — is worth the time. Cold smoking flavours without cooking and relies on a separate cure for safety, because the temperature range it uses is exactly where bacteria thrive.
The full TO SMOKE lesson — how to tell, where to practise it, what it carries to.