Carbonation calculator
Keg pressure from temperature and the fizz you want, or priming sugar for bottles.
Keg: regulator pressure
Pressure and temperature together set how much CO2 stays dissolved. Pick a style or enter the volumes of CO2 you want.
Gauge pressure at sea level. At altitude, add about 0.5 PSI for every 1000 ft (300 m) of elevation.
Bottles: priming sugar
Sugar added at bottling is eaten by the leftover yeast, which makes the CO2. The beer already holds some CO2 from fermentation, so the sugar only has to make up the difference.
PSI chart
| Temperature | 1.8 vol | 2.0 vol | 2.2 vol | 2.4 vol | 2.6 vol | 2.8 vol | 3.0 vol |
|---|---|---|---|---|---|---|---|
| 0 C (32 F) | 1.6 | 3.5 | 5.4 | 7.3 | 9.2 | 11.0 | 12.9 |
| 2 C (36 F) | 2.9 | 5.0 | 7.0 | 9.0 | 11.0 | 13.0 | 15.0 |
| 4 C (39 F) | 4.3 | 6.5 | 8.6 | 10.8 | 12.9 | 15.1 | 17.2 |
| 6 C (43 F) | 5.8 | 8.1 | 10.3 | 12.6 | 14.9 | 17.1 | 19.4 |
| 8 C (46 F) | 7.2 | 9.6 | 12.0 | 14.4 | 16.8 | 19.2 | 21.6 |
| 10 C (50 F) | 8.7 | 11.3 | 13.8 | 16.3 | 18.8 | 21.3 | 23.8 |
| 12 C (54 F) | 10.2 | 12.9 | 15.6 | 18.2 | 20.8 | 23.5 | 26.1 |
| 15 C (59 F) | 12.6 | 15.4 | 18.3 | 21.1 | 23.9 | 26.7 | 29.6 |
| 20 C (68 F) | 16.6 | 19.8 | 22.9 | 26.1 | 29.2 | 32.4 | 35.5 |
Typical ranges: British ales, stout, porter 1.8 to 2.3 volumes; Pale ale, IPA, American ales 2.2 to 2.7 volumes; Lagers and pilsners 2.4 to 2.8 volumes; Wheat beers and saison 3 to 3.5 volumes. Check the style you are brewing against the BJCP guidelines, which give carbonation descriptions for each style.
How it is worked out
The pressure comes from a polynomial fit to the solubility of CO2 in beer, with T in degrees Fahrenheit and V in volumes of CO2: P = -16.6999 - 0.0101059 T + 0.00116512 T squared + 0.173354 T V + 4.24267 V - 0.0684226 V squared. It is the formula built into most homebrew carbonation charts. Your gauge, line lengths and temperature probe all add small errors, so treat the result as the place to start and taste the beer.
Residual CO2 after fermentation is 3.0378 - 0.050062 T + 0.00026555 T squared (T in degrees Fahrenheit, the highest temperature the beer reached). One volume of CO2 weighs 1.96 g per litre. Table sugar gives 0.515 g of CO2 per gram and corn sugar (dextrose monohydrate) 0.444 g per gram, so the sugar needed is the missing CO2 divided by that yield.
Safety. Do not carbonate bottles beyond about 3 volumes unless they are rated for it, and never add extra sugar to be safe. A bottle that has too much sugar can burst. For kegs, check the pressure rating of the keg and regulator, and release the pressure completely before you open a keg: see how to open a Euro sanke keg.