Corn Sugar, dextrose, or priming sugar is commonly used during the secondary fermentation. It’s used to “prime” beer, cider or any drink that you want to naturally carbonate in the bottle. “Priming” is the act of adding small amounts of fermentable sugar to your beer just before bottling. This small amount of sugar is then consumed by the residual yeast which then produces carbonation inside of the sealed bottle. Corn sugar is the best priming sugar as it is easy for the yeast to consume and has a neutral flavor which will leave your beer tasting the way you brewed it. In addition, dextrose can be added to increase fermentable sugar in your beer without impacting the beer’s flavor profile. A pound of dextrose will add 1.042 points per gallon (PPG) to your specific gravity.
How much corn sugar do I use to carbonate?
A typical 5 gallon batch of beer requires 4 to 5 ounces of corn sugar. Boil 16-20 ounces of water, dissolve the priming sugar into the water, and continue boiling for about 5 minutes to sanitize. Allow the solution to cool then add your priming sugar mixture to your brew just before bottling.
Suggested CO2 Levels:
- Cask Ales = 1.5 to 2.0
- Ales = 2.3 to 2.6
- Lagers = 2.4 to 2.6
- Highly Carbonated Beers = 3.0 +
- Champagne is 6.3 which requires special bottles.
CO2 Level After Primary Fermentation
When a primary fermentation ends at 68F it will retain about 1 volume of CO2.
When a primary fermentation ends at 50F it will retain about 1.2 volumes of CO2.
4 oz of dextrose adds 1.48 Volumes of CO2 to a 5-gallon batch.
5 oz of dextrose adds 1.84 volumes of CO2 to a 5-gallon batch.
To convert from volumes to g/L: