Glossary
Hop utilisation
The proportion of a hop’s alpha acids that actually end up as dissolved iso-alpha-acids in finished beer — typically well under a third.
Also called utilization, utilisation.
Utilisation rises with boil time and falls with wort gravity, and is further reduced by losses to trub, yeast and foam. It is the reason a brewer cannot simply multiply alpha acid by weight to predict bitterness, and the reason different IBU formulas give meaningfully different answers for the same recipe.
Related
- Isomerisation — The reaction utilisation measures the efficiency of.
- IBU — What utilisation is used to predict.
More vocabulary
ABV · ABW · Alcohol unit · Alkalinity · Alpha acid · Apparent attenuation · Attenuation · Beta acid · Cohumulone · Degrees Lovibond
See every term on the glossary index.
Last reviewed 2026-08-16.
Evidence
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Only a minority of a hop’s alpha acids — commonly under a third, and often well under — end up as dissolved iso-alpha-acids in finished beer, with the rest lost to trub, yeast and foam.
Backed by a source
Sources: Brewing: Science and Practice — print; How to Brew (4th edition) — print