Upon completion of fermentation, a certain amount of CO2 remains in the beer. This amount of "residual CO2" depends upon the temperature of the fermentation. An ale fermented at 65°F will have 0.9 volumes of residual CO2 while a lager fermented at 50°F will have 1.2 volumes. To get the same carbonation in these two beers would require different amounts of priming sugar.
For the same weight, the various priming sugars generate different amounts of CO2. To add one volume of CO2, you need to add priming sugar at the following rates:
Priming Ingredient | Attenuation | grams/liter | ||
---|---|---|---|---|
Apparent | Real | |||
Cane or table sugar (sucrose) | - | 100% | 3.82 | |
Corn sugar (glucose/dextrose) | - | 100% | 4.02 | |
Dried malt extract (DME) | Munton & Fison | 75% | 60% | 6.8 |
Northwestern | 70% | 56% | 7.2 | |
Laaglander | 55% | 44% | 9.3 |
Please note that DME varies in its fermentability. Some example brand names are given with their approximate apparent attenuation (AA) values. Typically, DME has an AA of 70% to 75%, with the notable exception of Laaglander brand at 55%.
This widget is based on information from the following articles, for which I am indebted to the authors:
Note: The priming rates used here differ somewhat from those mentioned in Hibberd's and Draper's articles. For instance, Draper measures volumes of CO2 using 20°C as the reference temperature instead of 0°C as in Hall's article. I'm using Hall's convention here.
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