Draft Beer Pressure Pointers
Pressure is important when it comes to draft beer. It’s what keeps your beer carbonated and tasting fresh, and helps to push the beer out of the keg and into your pitcher or pint! Having too much or too little pressure will affect the way that your beer is dispensed and you won’t be able to enjoy it to its full potential, so make sure to pay attention!
The Basics of Draft Beer Pressure
About Head Space
As CO2 enters a keg it displaces your beer at a constant pressure. When you open the tap/faucet, beer flows out of the keg and into your glass, thanks to a push from the CO2. Not only does the gas encourage the beer to leave the keg, it replaces that beer by occupying the space that otherwise would be empty. This empty space in the keg is called “head space.” The CO2 fills the head space and maintains the pressure inside of the keg at the PSI set on your draft beer regulator. This constant PSI keeps the beer well carbonated by preventing the CO2 that comes dissolved in the beer from the brewery from leaking out.
Keep it Straight
Your CO2 tank must be stored upright or it won’t work properly. Storing the tank improperly can also cause expensive damage to your regulator.
Find the Magic Number
In general, most US produced ales and lagers should be dispensed at 10 to 12 PSI. Stout and other nitrogen-reliant keg beers are usually dispensed at 25 to 30 PSI.
For the specific dispensing pressure for a particular keg, check with your local keg distributor.
Too Much Pressure
Too much pressure will initially result in you beer coming out of the tap very quickly and very foamy. Essentially, your faucet will turn into a beer fire hose. In addition, if your beer is over-carbonated, the foam will appear tight and have large bubbles.
If you recognize the problem, it is easy to fix: promptly adjust your regulator pressure to the proper lower level, and draw a few foamy pitchers or bleed some of the extra pressure off by using the relief valve on the coupler. These measures will allow the system to balance it out again.
If the pressure is left too high for longer than 24 hours, CO2 will be forced into the beer, resulting in permanently over-carbonated and excessively foamy beer.
Too Little Pressure
Too little pressure will also cause the beer to become foamy, as the CO2 breaks free from the beer as it enters your glass. If the pressure is not raised to the appropriate level, your beer will eventually become flat.
A telltale sign of low pressure is when foam or bubbles visibly rise into the beer hose. If your beer is indeed under-carbonated, the foam will appear loose (sometimes described as “soapy” looking) with small bubbles.
To correct this problem, you should first make sure that your CO2 tank isn’t empty and is turned on. Then, check to see to what level your regulator is set. If your tank is functioning properly, your regulator is set to the right number and there are no obstructions in the air line, it is possible that your regulator or gauge needs to be replaced. Regulators do wear down and should generally be replaced every 4-6 years.