Determining the Right Pressure for Your Draft Beer System

regulator
A common question we get from our customers is: “At what pressure should I set my CO2 regulator for my beer to pour perfectly?” It’s a great question. To pour a perfect beer you need to counter the pressure flowing through your system with a regulator. When the pressure of your system and the pressure you apply from your regulator are equal, your system is balanced. If your system is balanced, you can pour about one gallon of beer per minute, or 2 ounces a second!

There is a rather simple formula to determine the appropriate pressure (PSI) for your draft beer system.

Pressure = (Length of Beer Line in Feet x Line Resistance) + (Gravity x .5)

All you need is 3 factors: Length of Beer Line, Line Resistance, and Gravity. This article will walk you through how to determine each of these factors, and thus, the ideal pressure for your draft beer system:

1. Determine Length of Beer Line

If you don’t know the length of your beer line, simply measure the length of line from your shank to your coupler. You will need this measurement to be in feet.

2. Determine Line Resistance

Line Resistance may also be called “Restriction Value”; the two terms are interchangeable. This just means the amount of pressure being pumped through a line. Every foot of beer line has a set, average Line Resistance. The smaller the Inside Diameter of your beer line, the higher the Line Resistance; The larger the Inside Diameter, the lower the Line Resistance. Below are two charts of Line Resistance for various common diameters of both vinyl and stainless steel beer lines.

Vinyl Beer Line
Line Length Hose Diameter Line Resistance
1 foot 3/16″ Inside Diameter 2.20 lb
1 foot 1/4″ Inside Diameter .65 lb
1 foot 5/16″ Inside Diameter .40 lb
1 foot 3/8″ Inside Diameter .20 lb
1 foot 1/2″ Inside Diameter .025 lb
Stainless Steel Beer Line
Line Length Hose Diameter Line Resistance
1 foot 1/4″ Inside Diameter 1.20 lb
1 foot 5/16″ Inside Diameter .30 lb
1 foot 3/8″ Inside Diameter .12 lb

Example:
Your beer line from tower to your keg measures 5 feet.
Your beer line is 3/16” Inside Diameter.
Multiply Length (5 Feet) X Line Resistance from the chart above (2.20 lb)
Line Resistance = 11 lb

3. Determine Gravity

The Vertical Rise or Vertical Fall of your draft beer system determines your system’s gravity. It is measured between the two horizontal planes of your system: the center of the keg and your faucet. On average, for each foot of gravity in your system a value of .45 PSI will need to be applied. You can round to .5 PSI to make this calculation easier.

Example:
Your faucet is 2 feet above your keg.
Your keg is 2 feet high.
Add your faucet height (2 feet) + you keg height / 2 (1 foot).
Gravity = 3 feet
(Note, in the end calculation, you will need to multiple Gravity by .5 PSI. We will walk you though this in the next step.)

4. Determining Ideal Pressure (PSI)

Now that you have each of the 3 factors, you are ready to determine the ideal pressure for your kegerator or draft beer system.
Use the formula from above:
Pressure = (Length of Beer Line (in feet) x Line Resistance) + (Gravity x .05)

Example:
Length of Beer Line = 5 feet
Line Resistance per foot = 2.2 lb
Gravity = 3 feet
(5 feet x 2.2) + (3 x .5)
11 + 1.5
Ideal Pressure = 12.5 lb

Setting your draft beer system to the right pressure will help you pour the perfect beer and eliminate waste.

So, get pouring.

If you need more help with figuring out the appropriate pressure for your draft beer system, or another draft beer questions, leave a comment below or hit us up on Facebook!

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41 Comments

  • Mark May 21, 2015 @ 3:46pm

    I have 2 1/6 barrels and I wait till they’re both empty to change them. When I do, I can never get them to pour at the same pressure even though the run off the same tank and regulator. All lines are equal at 5′ long. When they get down to 3/4 full, they balance out. But at first, one will come out like a fire hose and the other just a trickle.

    • Caleb Houseknecht May 22, 2015 @ 9:10am

      Hey Mark,

      That seems odd. Are they different styles of beer? The only thing I can think is if they’re different styles, your system is trying to find equilibrium, and once it’s balanced, they are pouring properly. Let us know!

    • Matthew Kedanis August 11, 2019 @ 5:12pm

      Draw off both kegs at same time..
      note; readjust regulator as needed

  • Hugh Topham June 18, 2015 @ 9:53am

    I am building a remote draft system from my basement to my taps. total rise is 11 feet, total line length is 15 feet. considering using 1/16 beverage line in a commercial trunk. Tap tower has 3 standard flow control faucets and two guiness taps. Can I serve both tap styles off the same tank using the same gas blend on regulators set up in series to give me the different serving pressures? Can I fill co2 tanks with the beer gas? My regulator is currently a lab grade o2 model set up on a standard 20lb tank filled with co2.

    • Caleb Houseknecht June 18, 2015 @ 10:20am

      Hey Hugh,

      This is a pretty complex question, but we may be able to help. I’m going to give you the number of one of our draft beer specialists here, Jim Rozycki. You can reach him directly at (716) 362-9212 ext. 198.

  • Evan Holloway August 27, 2015 @ 5:19pm

    I have a very unique system. Two separate bars fed from the same keg draw system. One bar runs an underground line (3/8ths) 160 feet, with a tower approx. 6ft off the ground. The second bar is an overhead 120ft run (also 3/8ths line), dropping into wall mounted taps approx 6.5ft off the ground. To further complicate matters, we have a keg shelving unit designed with space in mind, meaning half the kegs are on the ground, the other half approx. 4ft up. We have a bulk Co2 unit (400lbs) and a GreenAir nitrogen regulator for blending and pressures, so we don’t have to worry about switching canisters or the like. Any suggestions how I should calculate my pressures?

    • Andrew November 20, 2015 @ 8:19pm

      In the industry we typically set systems like that to 22lbs and play it by ear. When you have 2 dispensing locations like that, they can act differently. I’d recommend getting the one furthest away pouring correctly, and then messing with restriction of your lines going to the closer location by adding 3/16th line.

  • Chris Floyd September 13, 2015 @ 3:59pm

    Can you tap, untap, then retap a quarter barrel?

    • Caleb Houseknecht September 15, 2015 @ 11:05am

      Hey Chris,

      You can indeed, but if you’re using an air pump, make sure you drink it quick and keep it cold or else the CO2 will fill the empty space and the beer will go flat.

  • Andy Hayes October 17, 2016 @ 4:41pm

    My beer line is 1/4 inch and 6 feet long and I have 2 1/2 feet of lift.
    But If I get my pressure above 2 or 3 pounds all I get is foam.
    My calculations show I should be running at closer to 5 pounds.

    • Chris April 5, 2019 @ 5:10pm

      Hi Andy,

      We think you would be better off going with 3/16″ inner diameter tubing and setting your PSI at approximately 12.

  • Shawn January 12, 2017 @ 9:56am

    I’m building a keezer that will be kept in a closet with taps on the other side of the wall behind bar. I have 1/4 line / parts available that I’d like to use – but not sure if it will work or I need to move down to 3/16. Any help appreciated – here’s some details:
    – 4 kegs / taps
    – 4-way CO2 secondary regulators
    – from keezer to wall tap: ~5-6 feet with ~3ft vertical -line to run through PVC tubing, cooled via blower from inside keezer, with an insulated box for shanks.

    Key Question: Can I get 1/4 line to work for this system end to end – or would I need to run a ton of line to increase resistance more?

    Appreciate any help!

    • Shawn January 12, 2017 @ 10:14am

      Here’s the math I’ve done based on available keg line/regulation calculators I’ve found:

      Assuming:
      – Keg Pressure @12 PSI, targeting 1 PSI at tap
      – Height 1 foot above keg
      – 1/4 line resistance of 0.85
      (12-1-(1/2))/0.85 = 12.35 length needed.

      That said – any confirmation / feedback appreciated

    • Caitlin January 17, 2017 @ 9:22am

      Hey, Shawn! The three foot vertical is going to be a problem without resistance increasing. You may want to splice it to 3/16 at that point.

  • John March 1, 2017 @ 3:51pm

    Just tapped new 1/6 commercial keg and getting much foam. All system components are inside refrigerator maintained 34 -40 degrees. C02 pressure 12 psi. Party faucet on 11 ft 3/16″ beer line. Keg was pre-cooled 2 days prior to tap. That said – any confirmation / feedback appreciated. Thanks

  • Ted MacDonald March 18, 2017 @ 3:47pm

    Is there a minimum pressure? These formula seems to to just overcome line resistance and the gravity needed to get the beer to the faucet. If I do the calculation with 5 feet of 1/4 hose with faucet 1/2 foot above the 2 foot high keg I get 4 psi. It would seem you need a certain pressure just to keep the beer carbonated.
    I have a 30 litre keg in a fridge with the a hole drilled through the door for the shank and faucet.
    Thanks

  • Scott March 18, 2017 @ 10:28pm

    Balancing issues. Every equation I come up with ends the same, and I don’t think I’m balanced although my beer is pouring well in terms of carbonation, but it is a really slow pour.
    Specs:
    – 5/16″ vinyl line
    – 1′ height (center of keg up to the tap)
    – line length 6.5′
    – temperature is 4C (39.2F)

    Anything more than 4psi and I get wild pours. Of course at 4psi it take a long time to pour a pint (like 30 seconds approx.) I’m thinking I need a lot more line resistance (longer, narrower). Thoughts anyone ????

    • TedM April 8, 2017 @ 9:45am

      Scott: I think we may be having the same problem. Here is another article on balancing your system. It basically says set your psi to around 12 and use hose length / diameter /tap height to reduce pressure at tap to near 1. I think in fridge systems with a shorter run have opposite problems to commercial systems that have longer runs.

      http://beersmith.com/blog/2011/07/14/keg-line-length-balancing-the-science-of-draft-beer/

      • TedM April 8, 2017 @ 10:09am

        Here is a great explanation on Youtube complete with spreadsheet.

        • TedM April 8, 2017 @ 9:40pm

          Here is the link. I changed my 3/16 hose length from 4 to 10 feet and it really worked. Fixed the foam problem. It pours slowly but I will experiment with length on my next keg.
          https://www.youtube.com/watch?v=w6whE1jrVQ4

  • TedM April 8, 2017 @ 9:03am

    After doing a bit more research I think one point of the article is not necessarily to reduce the psi but to keep the original psi up, say 12 but to use a combination of length of hose and diameter to lower the psi at the tap. So lengthen the hose to reduce psi on gauge, maybe 12 to around 4 at the tap by having a longer hose.

    Could the author of the article or another export confirm this?

    • Scott April 24, 2017 @ 5:59pm

      TedM – thanks so much for the help!! I fully understand the principle of high pressure at the keg and low pressure at the tap. I am changing kegs today and am going to use 12′ of 5/16 ID line and see where that puts me. Unfortunately, the formula you had me look at earlier didn’t seem to solve anything, as it was telling me to use 134′ (or something) of line. I’ll post here to let you know how it goes.
      So I am going to have 12′ of 5/16 ID line. Center of keg to tap is about 9″ (.75′). I’m going to keep the line coiled as flat as I can on top of the keg, to avoid any peaks & valleys in the line. Fingers crossed!! Then I will play with my pressure and see where that puts me. I can always drop my line lower if needed as well.

      • ScottM April 27, 2017 @ 10:46am

        FAIL. I am about ready to pull my hair out. Let me be very clear. My lines, tap, spigot, fittings, connections etc are all clean. So… I have fridge temperature at 3C (38F). The center of the keg is 9″ below the tap. I have 12′ of 5-16″ ID vinyl tubing running from the keg to the tap. The tubing is coiled flat and laying on top of the keg. There are no peaks or valleys in the line run. And I still get nothing but wild pours and foamy beer on every pint. My pressure is set currently and 4psi. And I have had my gas regulator checked and calibrated. I am at a complete loss.

        • Caitlin April 28, 2017 @ 1:57pm

          Hi, Scott. You should try raising the pressure. We recommend 10-12 psi for 5 ft of 3/16″ line which has more restriction.

          • ScottM April 29, 2017 @ 8:47am

            Caitlin,
            Thanks!! I spent a load of time on Friday researching formulae, set ups etc. And the consensus data I found matches with what you said. My exact specs I’m going to try are 3/16″ line, 5′, 10 psi. Seems to be the general agreed specs. Fingers crossed…

          • Caitlin May 11, 2017 @ 9:53am

            Good luck! Let me know if it works out.

  • Ted May 24, 2017 @ 6:12am

    Hi,

    I understand how the different length and diameter of lines and gravity play a part in pressure needed to pass the beers from the kegs to the taps. Hence the pressure needed to pass beer out in a balanced manner is sum of the pressure from tubing and gravity.

    But firstly, should we consider the pressure at the facet to be 1 psi? I am assuming the formula mentioned in the article is setting the facet psi to be 0

    Secondly, as different beers have different co2 volumes and are served at different temperatures, hence they require different gas pressures to be expelled from the keg. In considering the ideal gas pressure to ensure the beer is neither over or under carbonated AND the overall system is balanced, I would need to have different tubings lying around? or to shift keg higher or lower to achieve this?

  • AdamJ July 8, 2017 @ 7:03am

    Hello.

    So I am looking at an 8 faucet cooled tower setup here. I sold house with my old kegerator. In my new house I am going to put the faucet on a bar upstairs (first floor). I just ordered a 17.5 cb ft chest freezer for the basement. I want to then run the lines up from the keezer. I am trying to figure out what diameter lines to use. It looks like your tower have lines connected already and that I should use 3/8 tubing from the keezer and then have them connect and restrict down the last six feet? Is that the best way to do this? I would rather have size lines run from keg to tap and have no coupler to worry about teaks. I plan to inclose the lines in insulated pvc pipe.

    So can I just use a single id vinyl tubing and if so what should that be for 18-20′ of line with approximate lift of 14′ (top of keg to tap)?

  • richard August 14, 2017 @ 7:50pm

    Hello, I was wondering if there is any different factors to consider when balancing draft lines if one is using pure co2 vs. a co2 nitro blend to push beer out of the keg?

    • Chris April 5, 2019 @ 5:02pm

      Hi Richard,

      The most important thing between Nitro and CO2 is that you’re using the proper components for each. For that, I would refer you to our Guinness on Tap blog piece, as it gets into the different components you would need between a CO2 beer and a CO2/Nitro blend.

  • Tay June 27, 2018 @ 3:18pm

    Hello-
    I need help. I just replaced my kegerator lines from the standerd 5 ft to 15ft to slow down my pour and the foam. I need help figuring out what my psi should be. Can someone please help?!?!?!

    • Chris April 5, 2019 @ 4:25pm

      Hi Tay,

      The PSI in your kegerator should be set to the carbonation level of the beer, typically between 10-14 PSI. You can check out our blog as a rough estimate based on styles, but not all beers in a certain style are the same.

      What you would need to adjust is the inner diameter of the line based on the PSI level you choose, which means balancing your system. It would be a good idea to contact our draft beer experts at Customer Care as well. They can be reached at 877.636.3673, Monday through Friday, 9:00 am – 6:00 pm EST. You can also reach out here. They will be able to discuss specifics about your system and answer your questions. Cheers!

  • Benjamin August 23, 2018 @ 9:22pm

    Hello All,
    So I did all the math on a 10ft vertical with a 15ft 1/4ID and it poured perfectly. Once I added the second line it is nothing but foam, Ultimately I plan on having a third keg tapped. Any advice on the math for a second and ultimately a third?

    Thanks!

    • Chris September 25, 2018 @ 10:50am

      Hi Benjamin,

      Sincere apologies for the delay in response. I spoke with our resident draft expert, and he would need additional information, such as the beer being poured, the temperature of the kegs and at the pour, how the air was split, if something like a tower was changed when the second line was added, and whether the system is shanks or towers. It would be best to contact our draft experts directly, and they can help you out with the math. They can be reached at 877.636.3673, Monday through Friday, 9:00 am – 6:00 pm EST. You can also reach out here. They will be able to discuss specifics about your system and answer your questions. Cheers!

  • nick February 23, 2019 @ 7:16pm

    My wife got me an Insignia Kegerator for VDAY, now I was little frustrated at first because the thermostat dial on the back is numbered 1-6 but no wording of which is cold and coldest, and I could not get the internal temperature of the fridge to be consistent (even with two thermometers at the top and bottom of inside), I wanted it to be . It would fluctuate between 10 degrees from top and bottom. Side note, only keg that will ever be in my kegerator is Coors Light, I know I know, most people hate it and think its gross, but that’s what I like lol.

    The Insignia Manual the kegerator came with is absolute horrible. No idea, of how to adjust and set up pressure and use coupler. Anyways….I hooked all the lines up, and tightened everything correctly. Now here is the one frustration…….the c02 air lines are all hooked up to coupler and c02, but nothing is turned on, 

    1. Do I tap the keg first, and then c02 tank on and then turn shut off valve to open and adjust pressure or vice versa?

    When adjusting pressure, once I turn all c02 on, and move regulator screw to correct pressure which for coors light I’m told is about 14-16psi, do I pull pressure relief pin on regulator wait a minute, then readjust a final time??

    Also, Do I ever have to pull the pressure relief pin on the coupler that attaches to the keg? Whether it be during tapping, or after tapping the keg, or after setting the pressure on regulator ???

    Thats basically my frustration/confusion…I am almost certain I ruined my first keg, because I had everything dialed in to my liking (except the first pour being sort of foamy) but ordered one of those amazon Coldpour tower fan coolers, and installed it, and everything went to hell…The tower cooler def made my tower faucet was much colder, but the temperature fluctuation was horrible inside the fridge from the cooler fan circulating the air inside the fridge, I let everything be overnight and when I woke up the temperatures on both bottom and middle ish area of fridge were 20 degrees. And I know I don’t/shouldnt have anything 20 degrees. 

    I took the tower fan cooler out, and went back to original set up without it, but now it seems I’m literally getting all foam on every pour, even filled a pitcher, filled a couple of cups, and nothing but foam. I had it perfect before, minus the first pour being half foam (which I woulda taken at this point, over ruining my keg now, and not knowing what I did to mess everything up). I want to figure this all out, before my next keg, or I’m giving up on this kegerator life before I even start it lol. I think my keg is all foam now, because even when I lifted it it felt a lot lighter. I def did not go through a 1/4 keg since last saturday being I only had a couple glasses during the week. Please help, because I would love to get this all corrected once and for all.

    • Chris February 25, 2019 @ 9:56am

      Hi Nick,

      The first thing I would refer you to is our “How to Set up a Kegerator” post, which has step-by-step instructions and a video on setting your draft system up. In that video, we did attach the coupler to the keg prior to opening up the air tank. You can complete steps 9 and 10 in that video (opening up the air tank and attaching the coupler to the keg) in either order you want. Both ways will work.

      As far as the pressure relief pins, the only time you need to pull those pins is when you are adjusting the pressure downwards. In that case, you would need to pull the pressure relief pins so that the pressure inside the keg adjusts to that newly lowered PSI.

      As far as the temperature, it’s difficult to say without knowing the specific kegerator you’re using, but try out each setting 1-6, let the fridge sit for a few hours, and see what each setting does to the temperature. You will want your keg fridge to be between 36-40 degrees Fahrenheit (38 degrees is ideal).

      Hope this helps! If you have additional questions about your system, feel free to give our draft beer experts at Customer Care a call. They can be reached at 877.636.3673, Monday through Friday, 9:00 am – 6:00 pm EST. You can also reach out here. They will be able to discuss specifics about your system and answer your questions. Cheers!

  • Buddy May 1, 2019 @ 12:02pm

    If I measure from floor to faucet (39 inches) then floor to top of keg (27 or 51 if stacked) and beer line comes from 12 inches under floor to 79 inches above floor when it enters cooler how do I figure gravity ? Thank you very much for your time

  • Dan June 5, 2019 @ 5:58pm

    Can I use the formula to determine pressure in reverse? I.e. I would like to lower the keg pressure to 8-10psi ( so not to over carbonate an English ale). Then using the gravity measurement to determine the length of line, apps 4ft. Would this work, or does the keg have to be at 10-12 psi?

  • Tarek August 3, 2019 @ 12:56am

    Hi I just used you calculator and got a pressure value around 55. Based on 15 ft of 3/16 in vinyl tubing plus 65 ft of 5/16 steel. This seems high to me.

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  • Adam J April 10, 2020 @ 5:57pm

    I’ve read a bunch of comments and the formula and everything and am at a loss. Have a 2 1/6 barrel system, all brand new, right now 1 keg in there. When I put the pressure at 12, it comes out crazy fast and is all foam.. When I drop the pressure down, all foam. By all foam I mean 3/4-7/8 of a pint foam. It’s 3/16th hose, 2’ long, about 18 inch rise. That should be around 5 psi off the formula. I’ve got it currently where it’s barely cracked open on the CO2. Thoughts?

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