Priming sugar calculator
Warm beer holds less dissolved carbon dioxide, so the amount of priming sugar depends on the highest temperature the beer reached after fermentation.
volumes CO2
Priming sugar
123.1g
- Per bottle
- 3.08
- CO2 already dissolved
- 0.861 volumes
- CO2 to add
- 1.539 volumes
- Bottles
- 40.0
- Equivalent in corn sugar
- 123.1
- Approximate bottle pressure at room temperature
- 1.35 bar
Show the working
- Beer volume = 20
- Target carbonation = 2.4
- Highest temperature after fermentation = 20
- Priming sugar = 1
- Bottle size = 500
- temp_f = 20 * 9/5 + 32 = 68
- CO2 already dissolved = 3.0378 - 0.050062 * 68 + 0.00026555 * 68^2 = 0.861 487
- CO2 to add = max(2.4 - 0.861 487, 0) = 1.538 51
- Equivalent in corn sugar = 1.538 51 * 20 * 4 = 123.081
- Priming sugar = 123.081 * 1 = 123.081
- Bottles = 500 > 0 ? 20 * 1000 / 500 : 0 = 40
- Per bottle = 40 > 0 ? 123.081 / 40 : 0 = 3.077 03
- Approximate bottle pressure at room temperature = 2.4 * 0.98 - 1 = 1.352
Values are shown to six significant figures here; the arithmetic itself runs on exact fractions and is only rounded where a number is printed.
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The formula
- residual CO2 volumes = 3.0378 - 0.050062 T + 0.00026555 T^2, with T in Fahrenheit
- about 4 g of dextrose per litre raises carbonation by one volume
Over-priming makes bottle bombs. Beer bottles are rated to around 4 to 5 volumes and champagne bottles rather more.
Use the highest temperature reached after fermentation finished, not the current one — the CO2 already left.