Primary fermentation
Term from the Brauwerkstatt brewing glossary, category “Fermentation and yeast”.
Explanation
The first, vigorous fermentation after pitching. The yeast ferments most of the sugar and krausen forms. It takes about 4–7 days for ales and 7–14 days for lagers.
Test your knowledge
What is krausen?
- A beer tap
- A Belgian glass shape
- The foam on top of the beer during primary fermentation
Show answer
Correct: The foam on top of the beer during primary fermentation. High krausen means vigorous fermentation. When it collapses, primary fermentation is winding down.
What happens if you add too much sugar at bottling?
- Nothing, the yeast ignores it
- The beer becomes alcohol-free
- Too much pressure – bottles can gush or even burst
Show answer
Correct: Too much pressure – bottles can gush or even burst. So weigh the sugar carefully and only bottle once primary fermentation is really finished.