carbonation
Krausening
Carbonate beer by adding actively fermenting wort rather than refined sugar — the traditional German method.
Pronounced KROY-zen-ing.
What is actually happening
A measured volume of wort at high krausen is blended into the finished beer. Its residual sugar carbonates the beer, and the fresh, active yeast it carries also reduces remaining diacetyl and acetaldehyde.
It was the compliant way to condition beer under the Reinheitsgebot, which permitted no added sugar.
Related steps and concepts
- Priming — The sugar-based alternative.
- Reinheitsgebot — Why German brewers used this method.
Also at the carbonation stage
Bottle conditioning · Force carbonation · Nitrogenation · Priming
See the whole process in order on how beer is made.
Last reviewed 2026-08-16.