United Kingdom
British beer strength collapses through two wars
Wartime restriction and gravity-based taxation drove British beer strengths down sharply, and they never returned to nineteenth-century levels.
Because duty was assessed on original gravity, weakening beer was the direct way to reduce cost, and successive restrictions ratcheted it downward. Brewing records show the scale of it clearly.
What was going on around it
An event on its own is a date. These are the periods it belongs to, where the argument about what changed is actually made.
Why it matters
The reason traditional British styles are substantially weaker today than the historical beers they are named after, and why "session strength" means what it does in Britain.
How well this is established
| Certainty | Documented. Supported by contemporary records that survive and are agreed on. |
|---|---|
| When | 1914–1950. Recorded as a period rather than a date because it happened over time. |
| Where | United Kingdom |
Styles this shaped
Traditions
- British cask ale — Beer that completes its fermentation in the container it is served from and is dispensed without added gas, at cellar rather than fridge temperature.
Either side of this
← 1908: A brewery statistician publishes the t-distribution · 1920: American Prohibition →
See the whole sequence on the beer history timeline.
Last reviewed 2026-08-16.