Keg Carbonation Calculator
Keg carbonation pressure is the CO2 regulator setting, in psi or bar, needed to dissolve a target number of CO2 volumes into beer at a given temperature. Cold beer absorbs CO2 far more readily, so the same pressure produces very different carbonation at 2 °C and 10 °C. At equilibrium — typically five to seven days — the carbonation level is fully determined by pressure and temperature.
Set the regulator, leave it connected, and the beer reaches equilibrium on its own in about a week.
How force carbonation works
CO2 dissolves into beer until the pressure in the headspace matches the pressure the dissolved gas would exert on its own. Hold the keg at a fixed pressure and temperature for long enough and the beer arrives at exactly one carbonation level — the one this calculator gives you.
Temperature dominates. Cold beer holds far more CO2, so the same 12 psi produces very different results at 2 °C and at 10 °C. If your kegerator runs warm, your beer will be undercarbonated at textbook pressures.
Pressure reference table
| Keg temperature | 2.0 volumes | 2.4 volumes | 2.8 volumes |
|---|---|---|---|
| 0 °C / 32 °F | 3.5 psi | 7.3 psi | 11.0 psi |
| 2 °C / 36 °F | 5.0 psi | 9.0 psi | 13.0 psi |
| 4 °C / 39 °F | 6.5 psi | 10.8 psi | 15.1 psi |
| 6 °C / 43 °F | 8.1 psi | 12.6 psi | 17.1 psi |
| 8 °C / 46 °F | 9.6 psi | 14.4 psi | 19.2 psi |
| 10 °C / 50 °F | 11.3 psi | 16.3 psi | 21.3 psi |
Set and forget, or burst carbonate
Set and forget is the method above: connect the gas at serving pressure and wait five to seven days. It is impossible to overshoot, which is its main advantage.
Burst carbonating — 30 psi for 24–36 hours, then down to serving pressure — is faster but easy to overdo, and an overcarbonated keg takes longer to fix than it saved.
Serving pressure and line balance
The pressure that carbonates the beer is also the pressure that pushes it, so your beer line has to be long enough to absorb it or every pour is foam. Roughly, a 5 mm (3/16 inch) line drops about 1 psi per 30 cm (1 foot). At 12 psi you want somewhere around 3–3.5 m (10–12 feet). Shortening the line and turning the gas down carbonates the beer wrongly instead of pouring it properly.
Bottling instead
If you are bottle conditioning rather than kegging, the priming sugar calculator works out the sugar addition for the same target carbonation.
Keg Carbonation Calculator — questions
What pressure should I set my kegerator to?
For an American ale at 2.4 volumes and 4 °C, around 11–12 psi. Adjust for your actual keg temperature — a fridge running at 7 °C needs noticeably more pressure for the same carbonation.
How long does force carbonation take?
Five to seven days at serving pressure. Shaking the keg speeds it up dramatically but makes the result hard to predict; if you have the patience, set and forget is more reliable.
My beer pours as all foam. Is it overcarbonated?
Sometimes, but more often the beer line is too short for the pressure, or the keg is warmer than you think. Check line length before you start venting the keg.
Carbonation targets, set per recipe
Brewgravity stores the target CO₂ volumes with the recipe and shows the matching keg pressure for your serving temperature — no chart to look up.
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