fermentation
Pressure fermentation
Ferment under applied top pressure to suppress ester and fusel production, allowing warmer and therefore faster fermentation without the flavour penalty.
What is actually happening
Elevated pressure inhibits the yeast pathways that produce esters and higher alcohols. A beer fermented at 18 °C under pressure can taste closer to one fermented cold at ambient pressure.
It is increasingly used to make lager-like beer on ale timescales, and to run ale strains warm without the banana-and-solvent character that would otherwise follow.
The equipment must be rated for it. This is a genuine safety consideration rather than a preference: a fermenter under pressure is a pressure vessel.
Typical conditions
| Temperature | 15–22°C |
|---|---|
| Scale | Used at both homebrew and commercial scale |
Ranges, not targets. These describe what is usual across the styles and breweries that use this step, and a value outside the range is a decision rather than an error.
What goes wrong here
Risks rather than certainties. This step does not cause these faults; getting it wrong can.
- Fusel alcohol — Harsh, solvent-like alcohol heat from fermentation run too warm or under stress — distinct from the pleasant warmth of a strong beer.
Related steps and concepts
- Bottom fermentation — The traditional route to the same clean character.
- Ester — What the pressure suppresses.
Also at the fermentation stage
Biotransformation · Bottom fermentation · Diacetyl rest · High-gravity brewing · Hop creep · Mixed fermentation · Open fermentation · Pitching · Primary fermentation · Spontaneous fermentation · Top fermentation · Yeast harvesting
See the whole process in order on how beer is made.
Last reviewed 2026-08-16.