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Speise Calculator
If you're looking to add fresh wort at packaging—whether you call it speise, gyle, kräusen, or something else—this calculator will help you dial in how much wort of a given gravity you'll need to hit your carbonation target.
Target carbonation level
Residual CO₂ after fermentation (typically 0.85 volumes)
Gravity of the speise wort in degrees Plato
Expected attenuation of your yeast (typically 75-85%)
Narziss Equation
% speise = ((desired CO₂ - current CO₂) / 0.46) / (OE - RE) × 100
Where RE = (OE × 0.19) + ((OE - (OE × (ADF/100))) × 0.18)
About Speise (Gyle/Kräusen) Priming
Speise is a traditional German method of carbonating beer by adding fresh, unfermented wort at packaging time. The residual sugars in the wort ferment in the bottle or keg, producing natural carbonation.
Advantages of Speise:
- No foreign sugars added - maintains beer purity (Reinheitsgebot compliant)
- Can enhance flavor complexity and body
- Traditional method used in many German beer styles
- Provides nutrients for bottle conditioning yeast
How to Use This Calculator:
- Desired CO₂: Enter your target carbonation level in volumes (2.5 is typical for most styles)
- Current CO₂: Enter the residual CO₂ after fermentation (usually 0.85 volumes at 68°F/20°C)
- Wort Gravity: Enter the gravity of your saved wort in degrees Plato
- ADF: Enter the expected apparent degree of fermentation for your yeast strain
Typical Carbonation Levels:
| Beer Style | CO₂ Volumes |
|---|---|
| British Ales | 1.5-2.2 |
| American Ales | 2.2-2.7 |
| German Lagers | 2.4-2.7 |
| Belgian Ales | 2.0-4.0 |
| Weizenbier | 3.3-4.5 |
| Temperature | Residual CO₂ |
|---|---|
| 32°F (0°C) | 1.70 volumes |
| 50°F (10°C) | 1.20 volumes |
| 60°F (15.5°C) | 0.97 volumes |
| 68°F (20°C) | 0.85 volumes |
| 77°F (25°C) | 0.73 volumes |
Special thanks to Josh Brengle and his team at Cervecería Hércules in Querétaro, Mexico, for sharing this calculator, based on equations from the work of brewing scientist Ludwig Narziss.
Need to convert Specific Gravity to °P? Check out our Specific Gravity-Plato Calculator.