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Beer line pressure math.

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  • Beer line pressure math.

    How do y'all pressurize lines between the keg & the bar?

    All lines, same length (the distance to furthest keg from the tap), right? Otherwise, you'd need a separate regulator per keg, right?

    You need to over-pressure the keg, to overcome line-resistance, right? By which I mean: if the beer was carbonated at, say, 12 psi at 38F, but you have 20' 3/16" lines, you're going to need to run 24-30 psi (depending on pour speed), right? ...And that doesn't over-carbonate the beer?

    Is there a formula/calculator to help-out with the keg-pressure math, based on line-size and length (and elevation keg-to-tap, etc.)?

    Am I totally off the rails, here? Am I thinking about it all wrong?

    Context: I'm drawing plans for my 1st taproom (formerly wholesale only) and trying to sort out the details of this part.


  • #2
    This should answer any questions about draught.


    • #3
      Thirsty_Monk already linked the best resource with the DBQM from the BA. Read it, use it, trust in it.

      If you've got that much of a run with a direct-draw system you will need to either use a blending system to incorporate nitrogen to keep your balance pressure up where it should be while avoiding over-carbonation or look into using beer pumps. We use a custom blending system that has two outputs and takes care of our nitro beers too. However, I know there are some real proponents of beer pumps on this forum and, the more I've heard and read, they can be a great solution too.

      Long story short, you will NEED separate regulators for each product line and you will not be able to operate this setup as a simple direct-draw system with a single line diameter and only CO2.


      • #4
        I use beer pumps for 10 of my 21 draft lines (the ones that don't use them are kegerators so they're not needed). They've been working flawlessly for over 3.5 years and make pouring beer with differing levels of carbonation a breeze. While I had a bit of trepidation when we installed them, that soon vanished when I saw how easy it was to dial them in.



        • #5
          We run 24 lines, 45' long, in two insulated and glycol-chilled trunks to two different locations. For this set-up, beer pumps are essential.

          Generally, the bulk of your lines will be 3/8", with short chokers of 3/16" at the faucets to reduce pour pressure to acceptable levels. Ideally, pressure at the faucet should be nearly zero, with a flow rate of about 1 gallon/minute.

          DL and consult the Draught Beer Quality manual from the link above. It's the bible for good draught beer service.

          BTW: Make your beer cooler right, tight and tidy.


          Beats this:

          Any day.

          PS: sorry for the links. I don't have time to deal with the BS of uploading the files right now.
          Timm Turrentine

          Terminal Gravity Brewing,
          Enterprise. Oregon.