All About Kegerator Gas Pressure

How do you determine your kegerator gas pressure?

You'll need to use a carbonation chart and know the brewer recommended CO2 volumes if possible.

See our general recommedations.

Learn to use a carbonation chart

Starting, for example, at 38 degrees for a beer that requires 2.8 volumes of CO2. This beer has to be maintained at 14 applied PSI to keep the desired carbonation level. However, this beer also has to be pushed out to the faucet.

Learn How to Use a Gas Regulator

In order to accomplish this properly, the resistance of the system has to be considered. The parts of the draft system applying resistance includes the keg coupler, shank and faucet assembly, the beer line, the height of the faucet above the beer pick-up point (bottom) of the keg and finally the altitude above sea level. Each of these parts has a predetermined resistance value and the total resistance in the system can be calculated.

The pressure applied to the beer in the keg has to also perform the task of delivering the beer to the faucet. If the required applied pressure for carbonation maintenance is equal to the total PSI resistance of the system, the two are in balance and the beer can be poured properly without changing the character of the beer.

If they are not equal, action is needed.

For example, if the required maintenance pressure is 14 PSI, but the resistance in the system adds up to 17 PSI the beer will not pour properly. It will pour slowly. In this case it might seem logical to adjust the applied pressure up to 17 PSI. This might work temporarily, but within a few days the beer in the keg would become over-carbonated because of the high gas pressure.

So the solution is to lower the resistance in the system.

The beer line applies resistance according to its diameter, length and type. In most direct draw systems the line used is 3/16 inch diameter vinyl hose. This size hose has a resistance value of 2.7 pounds per foot of length. This factor in resistance can be adjusted by altering the length or diameter of the hose while the other factors such as the coupler etc cannot easily be altered.

Learn to calculate the resistance in your system

In bars that have high volume it is acceptable to have the system “balanced” at slightly higher pressure or “push pressure” without altering the beer. If you’re changing kegs daily or better it is OK to deliver slightly higher pressure to the keg because it won’t have time to over-carbonate.

Straight carbon dioxide is always the best choice for pressurizing kegerator systems. The exception is with Guinness and similar beers that require a nitrogen/CO2 mixed to allow high pressure dispensing.

Learn how to serve Guinness, Beamish, Boddington's and other similar beers.

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