Forced carbonation pressure calculator
Cold beer absorbs CO2 readily, so the colder the keg the lower the pressure needed for the same carbonation.
volumes
m
psi per metre
m
Regulator pressure
10.79psi
- In bar
- 0.744
- In kilopascals
- 74.4
- Beer line length for a balanced system
- 0.67 m
- Pressure lost in the line
- 45.00 psi
- Pressure at the tap Aim for around 1 to 2 psi at the tap for a clean pour.
- -34.93 psi
Show the working
- Target carbonation = 2.4
- Keg temperature = 4
- Beer line length = 3
- Line resistance = 15
- Height from keg to tap = 0.5
- temp_f = 4 * 9/5 + 32 = 39.2
- Regulator pressure = -16.6999 - 0.0101059 * 39.2 + 0.00116512 * 39.2^2 + 0.173354 * 39.2 * 2.4 + 4.24267 * 2.4 - 0.0684226 * 2.4^2 = 10.7918
- In bar = 10.7918 * 0.0689475729316836 = 0.744 065
- In kilopascals = 10.7918 * 6.89475729316836 = 74.4065
- Pressure lost in the line = 3 * 15 = 45
- height_drop = 0.5 * 1.4504 = 0.7252
- Beer line length for a balanced system = 15 > 0 ? (10.7918 - 0.7252) / 15 : 0 = 0.671 104
- Pressure at the tap = 10.7918 - 45 - 0.7252 = -34.9334
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
- the pressure-temperature-volumes relation is the standard empirical fit used in brewing charts
- balanced line length = (keg pressure - height correction) / line resistance
A foamy pour is nearly always an unbalanced system rather than over-carbonation: too little line resistance for the pressure.
Carbonating at a higher pressure to speed things up works, but you must then drop to serving pressure or the beer keeps absorbing.