Glossary
Thiol
Sulphur-containing aroma compounds detectable at extraordinarily low concentrations, responsible for much of the tropical, passionfruit and blackcurrant character of modern hops.
Also called thiols, polyfunctional thiols, 3mh, 4mmp.
Thiols are perceptible in parts per trillion — orders of magnitude below the threshold for hop oils. They are a large part of why varieties like Nelson Sauvin and Citra smell so unlike traditional hops.
Many arrive in the wort bound to other molecules and inactive, and are released by yeast enzymes during fermentation. This is the best-understood mechanism behind biotransformation, and the basis of "thiolised" yeast strains bred to release more of them.
Related
- Biotransformation — How bound thiols are released.
- Hop oil — The other main aroma class.
- Nelson Sauvin — A variety strongly associated with thiol character.
More vocabulary
Adjunct · Aroma hop · Base malt · Bittering hop · Black malt · Brettanomyces · Candi sugar · Chocolate malt · Crystal malt · Dextrin
See every term on the glossary index.
Last reviewed 2026-08-16.