Calculator
Priming Sugar Calculator
It tells you how many grams of priming sugar you need to bottle carbonate, based on the volume, the temperature the beer fermented at and the carbonation the style calls for.
Priming Sugar Calculator: how to use it
- Enter the liters (or gallons) you're going to bottle.
- Enter the highest temperature (°C or °F) the beer reached at the end of fermentation (not its temperature now).
- Choose the carbonation you want (volumes of CO₂) and the sugar you're going to use.
How it works
When fermentation is done, the beer already holds some dissolved CO₂, and the colder it has been, the more it holds. That's why temperature matters: you have to subtract that gas from the level you're aiming for. The yeast supplies the rest by eating the sugar you add at bottling. One volume of CO₂ is about 2 grams per liter (0.27 oz/gal), and each gram of sucrose produces half a gram of CO₂: that works out to about 3.9 g of sugar per liter (0.52 oz/gal) for each missing volume. Dextrose gives a bit less gas per gram, and dry malt extract quite a bit less, so you need more of them.
Frequently asked questions
Can I use regular white sugar?
Yes: white table sugar is sucrose and works perfectly. Dissolve it in a little boiled water and mix it into the beer before bottling.
What happens if I use too much sugar?
The beer comes out overcarbonated, foams over when you open it and, in the worst case, a bottle can burst. Only bottle once the gravity has held steady for three days, and weigh the sugar.
How long does it take to carbonate?
About two weeks at room temperature (18–22 °C / 64–72 °F). Somewhere cold it takes quite a bit longer, because the yeast works more slowly.
Why is my beer flat?
The usual suspects: the bottles are somewhere cold, the two weeks haven't passed yet, a cap isn't sealing properly or, after a very long conditioning period, there's little yeast left. Move them somewhere warm and wait.