Glossary
Gushing
Beer foaming violently out of the container on opening, without having been shaken or warmed.
Also called gusher, overfoaming.
The full record
Gushing has its own catalogue entry with the detail this page summarises — causes, thresholds, related styles and evidence.
Gushing — Beer that erupts on opening, caused either by refermentation in the package or by fungal proteins from mould-affected barley.
Two quite different causes. Over-carbonation — from over-priming, from an unfinished fermentation restarting, from hop creep, or from wild-yeast contamination — is the common one, and it is a package-pressure problem.
The other is a genuine gushing factor: hydrophobin proteins produced by Fusarium mould on the barley in the field. That variety survives the whole brewing process and causes gushing in beer that is correctly carbonated.
A gusher with no explanation and an off aroma is one of the few genuine reasons to discard beer, because it may indicate an infected package.
Related
- Bottle bomb — The dangerous extreme.
- Hop creep — A modern cause.
- Priming — The step that most often causes it.
More vocabulary
Acetaldehyde · Autolysis · Bottle bomb · Diacetyl · DMS · Lightstrike · Oxidation · Staling
See every term on the glossary index.
Last reviewed 2026-08-16.