What Is Force Carbonating?
- Force carbonating is adding carbonation to a liquid by pressurising the container it is in with CO2 for long enough that it absorbs into the liquid as bubbles.
- The colder the liquid, the higher the pressure and the more surface area is in contact between the liquid and the CO2 the faster the gas will absorb.
- The fastest way is to inject as much gas as possible into a vessel that is only half full of very cold liquid and shake it vigorously or inject the gas from the bottom of the liquid (like a sodastream machine). If you wanted to make sodawater quickly this is fine but beer, cider, kombucha etc need a little more finesse or you end up with an over carbonated foamy mess.
What Is The Most Reliable Way To Force Carbonate?
- Carbonation level is determined by what volume of CO2 is dissolved into the liquid.
- CO2 stops dissolving when equilibrium is reached ie no more can enter the liquid at the current pressure and temperature..
- Equilibrium point is determined by the pressure in the vessel and the temperature of the liquid.
- The colder the liquid, the more gas can dissolve into it.
- The higher the pressure the more gas is forced into the liquid.
- Once equilibrium is reached it doesn't matter how long the vessel is left, so long as the pressure and temperature remain the same the carbonation level will stay the same and no more gas will be used or absorbed.
- Using this information we can produce exactly the level of carbonation we want.
Carbonation Table - Temperature, Pressure and Beer Style
- To use the chart above you 1st choose the style of beer from the colours at the bottom. The most common styles (lager, ale amber) have around 2.5 volumes of CO2 dissolved in them to be perfectly carbonated and are the yellow band across the centre.
- After that choose the temperature your liquid is being stored at while carbonating. (example a fridge at 5 deg). Find this temperature on the left side and follow it across till you hit your beer style (in our case we would hit the yellow band in the 5 columns just to the left of centre).
- This tells us that we would need to set our CO2 pressure to 9-13 PSI to get the correct level of carbonation.
- How long it takes to reach the correct level depends on the volume of liquid you are trying to carbonate and the temperature. The warmer it is and the larger the volume of liquid the longer it will take to absorb the gas.
