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%.
Caution
Please exercise caution
in using the results from this calculator. If the amount of priming
sugar recommended seems excessive then use common sense and only
use the amount you're accustomed to using, because it's quite likely
you made a mistake when entering your numbers. Too much priming
sugar or bottling a batch of beer that is not done fermenting can
cause exploding bottles! Also, some bottles are capable of
holding more pressure than others, so don't carbonate bottles to
higher pressures than the beer that came in them. This information
is provided "as is" and the author assumes no liability for the
use of the results from this calculator.