Krausening (or Speise) is a traditional German method of carbonating beer by adding a portion of actively fermenting wort. It is used in Reinheitsgebot-compliant brewing where priming sugar is not permitted.

When should I add the krausen?

Add krausen at or near high krausen (peak fermentation activity, typically 24-48 hours into fermentation) for the most active yeast and predictable carbonation.

Can I use saved wort instead?

Yes. Some brewers save a portion of unfermented wort (Speise) from brew day, refrigerate it, and add it at packaging time. Calculate the same percentage of batch volume.

How does krausening compare to priming sugar?

Krausening produces finer, more integrated carbonation and is the traditional German method compliant with Reinheitsgebot. Priming sugar is simpler and more accessible. Both achieve the same carbonation level, but many brewers report that krausened beers have a smoother mouthfeel.

When should I harvest the krausen beer?

Harvest krausen beer at high krausen — the peak of active fermentation, typically 24-48 hours after pitching. The wort should have a thick, rocky foam and be visibly active. This stage has the highest concentration of active, healthy yeast cells.

BrewCalcs

Krausen Calculator — Natural Carbonation

Calculate krausen addition volume for natural carbonation (Speise).

Batch Volume

Wort OG

Target CO2 Volumes

How We Calculate This

Krausen Calculation

The volume of krausen needed depends on your target CO2 volumes and the original gravity of the wort. Higher gravity wort produces more CO2, so less volume is needed.

Frequently Asked Questions

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Last updated: 2025-02-20

All calculations are estimates. Always verify values and adjust based on your equipment and ingredients.