Keg Carbonation Calculator

Keg carbonation uses CO2 pressure applied at a controlled temperature to dissolve a target amount of carbon dioxide into your beer. The CO2 solubility in beer follows Henry’s Law: the amount dissolved is proportional to pressure and inversely related to temperature.

Target CO2 Volumes Formula:

The relationship between pressure, temperature, and dissolved CO2 is given by the empirical formula:

Pressure (PSI) = −16.6999 − 0.0101059×T + 0.00116512×T² + 0.173354×T×V + 4.24267×V − 0.0684226×V²

where T is beer temperature in °F and V is the target CO2 volumes. At 38°F and 2.4 volumes this gives about 10 PSI, matching standard carbonation charts.

In practice brewers use a pre-calculated carbonation chart. The two inputs are:

• Beer temperature, in Fahrenheit, and it has to be stable. A kegerator that swings 6 degrees overnight will over-carbonate on the cold end and gas out on the warm one.
• Target CO2 volumes, which is style-dependent (see the table below)

Typical CO2 volumes by style:

Worked example: Beer stored at 38°F. Target: 2.4 volumes (American pale ale) From carbonation chart: ~9–10 PSI

Set regulator to 10 PSI and wait 7–10 days at temperature for equilibrium carbonation (the most reliable method).

Forced carbonation (faster method): Set to 30 PSI for 24 to 36 hours while rolling the keg to agitate, then drop to serving pressure of about 10 to 12 PSI. That gets you there in a day or two rather than a week, at a real risk of overshooting. If you forget it overnight at 30 PSI you will be venting and waiting for days to get back down, which is longer than set-and-forget would have taken in the first place.

Serving pressure: Typically 8–12 PSI through a 5–6 foot beer line produces a proper pour without excessive foam.