Glossary
Cask conditioning
Completing fermentation and carbonation inside the cask the beer is served from, so the beer is still live when it reaches the drinker.
Also called cask conditioned, secondary fermentation in cask.
The full record
Cask conditioning has its own catalogue entry with the detail this page summarises — causes, thresholds, related styles and evidence.
Cask conditioning — Complete fermentation and carbonation inside the cask the beer will be served from, so it arrives at the drinker alive.
The beer leaves the brewery unfinished. A small quantity of fermentable material and live yeast remain, and the secondary fermentation in the pub cellar produces the beer’s gentle natural carbonation.
This is what makes cask beer both distinctive and demanding. It has to be handled by the cellar — stillaged, vented, allowed to drop bright, and served within a few days of broaching, because once air enters as beer leaves, oxidation and souring begin.
Related
- Real ale — The campaigning definition built around this practice.
- Cellar conditioning — The pub-side half of the process.
- Venting — Releasing excess condition before service.
- Cask, hand-pulled — How the finished beer is dispensed.
More vocabulary
Arrested fermentation · Barrel ageing · Batch sparging · Biotransformation · Blending · Bottle conditioning · Bottom fermentation · Burtonisation · Centrifugation · Cold break
See every term on the glossary index.
Last reviewed 2026-08-16.