Force Carbonation Time Calculator
Force carbonation time is the number of days a keg takes to reach a target CO₂ level at a given pressure and temperature. CO₂ dissolves into beer following an exponential approach to equilibrium — the rate depends on the pressure differential between applied gas and the equilibrium pressure for the target carbonation, and on the beer temperature.
Set and forget works, but it helps to know roughly when the beer will be ready.
How it works
CO2 dissolves into beer until the dissolved gas pressure matches the headspace pressure — that is equilibrium, and the keg carbonation calculator tells you what pressure achieves a given carbonation level.
Getting there takes time. The absorption follows an exponential curve: it is fastest at the start, when the pressure difference is largest, and slows as the beer approaches equilibrium. At a typical serving pressure of 11–12 psi and 4 °C, full carbonation takes roughly 5–7 days.
Set and forget vs burst carbonation
Set and forget is the standard method: connect the gas at the pressure your target CO2 requires and leave it for a week. It is impossible to overshoot, because equilibrium is self-limiting.
Burst carbonation applies a much higher pressure — typically 30 psi — for 24–48 hours, then drops to serving pressure. It is faster but easy to overdo, and an overcarbonated keg takes days to vent back down.
This calculator estimates the time for the set-and-forget approach. Burst carbonation is fast enough that timing it by feel is more practical than by formula.
What moves the time
- Pressure above equilibrium. More excess pressure drives CO2 in faster. At 20 psi where equilibrium is 12 psi, carbonation is noticeably quicker than at 13 psi.
- Temperature. Colder beer absorbs CO2 more readily, so the same pressure carbonates faster at 2 °C than at 8 °C.
- Surface area. A half-full keg carbonates faster than a full one because the gas–liquid surface is larger relative to the volume. Shaking exploits this to the extreme.
Force Carbonation Time Calculator — questions
Is this exact?
No — it is an estimate. The actual time depends on keg geometry, fill level, agitation and how well sealed the connections are. Treat it as a planning figure, not a stopwatch.
Will shaking the keg speed it up?
Yes, dramatically — shaking increases the gas–liquid contact area. You can carbonate a keg in minutes by rocking it at 30 psi, but the result is hard to control and easy to overcarbonate.
What if my pressure is below the equilibrium pressure?
The beer will never reach your target carbonation at that pressure. Either raise the pressure or lower the target. The calculator will tell you what carbonation level you will actually reach at your current setting.
Carbonation that plans itself
Set your target CO₂ in the recipe and Brewgravity tells you the pressure and the wait — the same math, built into the brew-day timeline.
There will always be a free plan · no credit card · drag in BeerXML or BeerJSON