Glossary
Flocculation
Yeast cells clumping together and dropping out of suspension once fermentation nears completion.
Pronounced flock-yoo-LAY-shun.
Also called flocculent, floc, yeast settling, yeast dropping out.
The full record
Flocculation has its own catalogue entry with the detail this page summarises — causes, thresholds, related styles and evidence.
Flocculation — How readily yeast clumps together and drops out of suspension at the end of fermentation.
Flocculation is a strain property and a major reason particular yeasts suit particular styles. Highly flocculent English ale strains drop bright quickly and leave a clear beer, but can drop before finishing, which is why traditional British brewing rouses the yeast back into suspension. Low-flocculating strains, including most used for hazy IPA and many Belgian strains, stay suspended and contribute to both haze and continued conditioning.
Related
- Attenuation — Early flocculation is a common cause of under-attenuation.
- Finings — The intervention used to force it.
- Rousing — Putting dropped yeast back into suspension.
More vocabulary
Arrested fermentation · Barrel ageing · Batch sparging · Biotransformation · Blending · Bottle conditioning · Bottom fermentation · Burtonisation · Cask conditioning · Centrifugation
See every term on the glossary index.
Last reviewed 2026-08-16.