Glossary
Top fermentation
Warm fermentation with ale yeast, which collects at the surface of the fermenting beer and can be skimmed from the top.
The full record
Top fermentation has its own catalogue entry with the detail this page summarises — causes, thresholds, related styles and evidence.
Top fermentation — Ferment warm with Saccharomyces cerevisiae, producing the ester and phenol character that distinguishes ales from lagers.
The name comes from the practical observation that ale yeast rises with the krausen and could be cropped from above. In a modern tall cylindroconical vessel the behaviour is much less pronounced, so the term now functions mainly as a synonym for ale fermentation.
Related
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.