What equation does this use?

It uses the standard brewing carbonation relationship, where dissolved CO2 volumes are a function of temperature and the absolute partial pressure of CO2. CO2 solubility rises steeply as temperature falls, following Henry's Law behaviour fitted to brewing data.

What is a CO2 'volume'?

One volume of CO2 means a volume of dissolved carbon dioxide equal to the volume of the beer at standard conditions. Most beers sit between 2.2 and 2.7 volumes; British ales are lower and German wheat beers and many sparkling styles are higher.

How do I degas beer in a closed system?

Lower the head pressure and/or warm the beer. Both reduce the equilibrium dissolved CO2, so gas comes out of solution. The tool lets you compare dissolved CO2 at different pressures and temperatures to plan a controlled release.

Why does cold beer hold more CO2?

Gas solubility increases as temperature drops, so cold beer at a given pressure dissolves more CO2 than warm beer at the same pressure. That is why you set lower regulator pressures when force-carbonating cold.

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Beer Dissolved CO2 & Degassing Calculator

The Beer Dissolved CO2 & Degassing Calculator tells you how much carbon dioxide is dissolved in beer at equilibrium for a given temperature and head pressure. That lets you set the right regulator pressure for force carbonation — or plan a controlled degas in a closed fermenter or keg.

How it works

CO2 solubility in beer depends on temperature and the partial pressure of CO2 above the liquid. As beer gets colder, it holds more CO2 at the same pressure; as pressure rises, more gas dissolves. The tool uses the widely used empirical carbonation relationship fitted to brewing data:

volumes = (P + 14.695) × (0.01821 + 0.09011 × e^(−(T−32)/43.11)) − 0.003342

where P is the gauge pressure in psi and T is the beer temperature in °F. The P + 14.695 term converts gauge to absolute pressure. The result is in CO2 volumes, which the calculator also converts to grams per litre (g/L ≈ volumes × 1.96).

Carbonation and degassing

To carbonate, pick the target volumes for your style and read off the pressure to hold at your serving temperature. To degas a closed vessel, lower the head pressure or warm the beer — both reduce the equilibrium dissolved CO2, driving gas out of solution. Comparing two scenarios in the tool shows exactly how much CO2 you will release.

Example and notes

At 4°C (39°F) and 12 psi, beer carbonates to roughly 2.4 volumes — a typical lager level. Drop the pressure to 0 psi and the equilibrium dissolved CO2 falls sharply, which is how spunding and pressure release work. Equilibrium takes time to reach: forced carbonation at a set pressure can take days at rest, faster if you agitate. Use the figures to plan, and confirm by taste and gauge.