Draft Beer Systems: Maintaining Proper Pressure

Keep your draft beer pouring perfectly and improve the quality of your brew by maintaining the proper pressure.

As CO2 enters a keg it displaces your beer at a constant pressure, replacing poured beer by occupying the space that otherwise would be empty. The empty space in the keg is referred to as “head space.” The CO2 fills the head space and maintains the pressure inside of the keg at the PSI set on your regulator. Maintaining a constant PSI keeps your beer perfectly carbonated by preventing the CO2 that’s dissolved in the beer from leaking out of the keg.

Double Gauge Premium Nitrogen RegulatorHow best do you maintain proper pressure? Here’s some tips:

Store your air tank upright
Your CO2 tank will not work properly if it’s not stored upright, and could even cause damage to your regulator.

Find your PSI
Most US-produced ales and lagers dispense well at 10-12 PSI, while stouts or other nitrogen-dispensed brews work well at 25-30 PSI. If you’re having problems utilizing these general guidelines, check with the local distributor from which you got the keg; they may have a suggestion for that particular beer.

Too much pressure? Indicators and how to fix it:
Initially, too mush pressure results in fast pouring, extremely foamy beer. Think fire hose. Foam in over-carbonated beer will appear tight with large bubbles.

Fix over-carbonated beer by immediately adjusting your regulator to a proper, lower level and either pour off a few foamy pitchers or bleed off some of the extra pressure via the relief valve on the regulator. This way, your system can find its balance. If you leave your system at too high a pressure for longer than 24 hours, your keg will be permanently over-carbonated and excessively foamy.

Not enough pressure? Indicators and how to fix it:
If air pressure isn’t high enough, your beer will be over foamy too, but it will look more loose than if there’s too much pressure; small bubbles that are often described as “soapy” looking. Another sign that your beer is under-carbonated is if foam and/or bubbles actually rise into the beer line. If you don’t raise pressure to a proper PSI soon enough, your beer will become flat.

To correct low pressure, first check to make sure your air tank isn’t empty and that it’s turned on. This seems like a “duh” suggestion but sometimes it’s the simplest issue that causes the problem. Next, check your regulator to be sure it’s set at the right level. If the tank is functioning and there aren’t any obstructions in your air line, aaand your regulator is set to the correct PSI, then most likely your regulator or gauge needs to be replaced. Unfortunately, regulators do wear out and typically need to be replaced every 4-6 years or so.

Hope these pressure pointers do you and your draft beer some good. Cheers!



  • Amgad March 22, 2011 @ 2:53pm

    My name is Amgad I’m a restaurant and bar manager. my draft beer system is not working (the beer comes out warm) if you can fix it for me please email me back ASAP.

  • Hannah March 22, 2011 @ 3:01pm

    Amgad – Is your keg properly refrigerated? If so, you’ll also want to make sure the beer lines are kept cold so that beer isn’t getting warm en route from keg to beer glass. Are the beer lines in the keg fridge or at least properly insulated?

  • Steve May 11, 2015 @ 5:38pm

    when i first tap a keg (always a craft brew IPA) it tastes great as intended for about 5 days or so. After that, its still okay, but not great like it was in week 1. After the second week, another drop off in taste. Still drinkable, but a far cry from two weeks ago. Am i doing something wrong with my CO2 pressure or is this just the nature of the beast? I use 5 gallon kegs in a refridgerator conversion kegerator. temp 37F, pressure 10-12psi. No foaming issues, great pours every time. (seven foot beer lines took care of the foaming). At 10-11 psi i get bubbles developing above the coupler (suggesting low pressure?) if i raise the pressure just to the point that those bubbles dont form (12-13psi), the beer loses flavor almost instantly (over carbonation?) What am i doing wrong?

    • Caleb Houseknecht May 12, 2015 @ 12:36pm

      Hey Steve,

      A couple of things come to mind. First, an IPA will have a change in flavor as time progresses from the point of tapping the keg. Also, remember the beer in the line is semi-exposed to air, and the oxidization that occurs is unavoidable. The more carbonated the beer is, and the colder it is, the less flavor your tongue processes. If you are experiencing off flavors you may have some problems with your lines or hardware. Make sure to clean your lines after every keg.

      Also, 7 feet of beer line indicates to me that you should be on the higher end of 12-15 psi. I would let the beer sit for a minute or two to reduce temp and let off some of the gas. See how that work. Hope that helps!

  • Ron June 29, 2015 @ 7:43pm

    I’m having a problem with pressure. I set the co2 at 10. But as the night progresses it keeps rising and rising and rising. I turn the knob to where it’s barely on and still it rises. The only way that it stops is to turn off the co2 completely. What am I screwing up.

    • Caleb Houseknecht June 30, 2015 @ 12:49pm

      Hey Ron,

      It sounds like it may be a Regulator issue. Try turning off of the shut off going to the keg. Leave the gas on to the regulator overnight. See if the pressure changes to the regulator, or if it holds…

  • Josh November 21, 2015 @ 6:16pm

    I am having an issue where the pressure seems to trail off while pouring to the point that it stops. I come back 5 minutes later and the pressure is good, but then trails off throughout the pour. The CO2 looks good and gauge indicates plenty of gas. I have the pressure set at 12psi. I don’t see any kinks in the line or anything like that. Any ideas? Thanks

  • Chris November 24, 2015 @ 3:35pm

    I have a keezer with three kegs that feed a tower in my bar. The length of beer line for each is approx 12 feet (3/16″ line). Beer is stored at 36 degrees. Where should my psi be set? Currently around 12 – pours a little slow, but beers seems adequately carbonated. Trying to avoid over carbonating, but everything I read indicates I should have the psi set much higher with the length of line I have.

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