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Help With Draft system

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  • Help With Draft system

    Hi , we are having some issues with our draft system at a new location. It is 16 tap system divided into two separate trunk lines each of which are glycol cooled. The kegs are tapped in a cold room at 36 degrees, each keg has a fob , but we have a manifold co2 gas system instead of separate gas regulators for each tap. The trunk lines exits the cold room through the ceiling rising about 8 feet then parallels the ceiling for about 40 feet then transitions to a 90 degree fall for 14 feet to the the taps. It is a 3/8 inch line from the trunk to the tap completely with not restrictions. We use Co2 to push our beer and the regulator is set from 14 to 16 psi. We are getting allot of foaming and gurgling from the taps when we try to poor a beer. I expected some foaming but not like this. I designed and installed the system and I am not an engineer so I am asking for help. How do I reduce the foaming.

    I think what is happening is that while the tap is closed the beer pressure in the line is balanced, however when a tap is opened the beer in the part of the line going down to the tap flows at a faster rate than the beer leaving the keg. This causes co2 to nucleate out of solution and a negative pressure which causes more co2 to come out of solution. I feel that installing a smaller diameter restriction line from the tap to the trunk line would solve this issue. I have tried increasing the pressure on the co2 pushing the beer which has not helped much, and makes the beer flow at a higher velocity creating other challenges. Am I right and if so how long should the restriction line be to equalize head pressure and balance the line. This issue is happening on both trunk lines any help would be great thanks.

  • #2
    Hi, Jamie. I'm no expert in draft line design, but what faucets are you using? You may find that flow control faucets may help you control the flow and reduce that foaming. Alternatively, you may need to cool your beer down a little further so you can reduce the CO2 pressures you are using.

    You may find that Micromatic can help you out; I recommend giving them a call: (866) 327-4159
    Brewery Design Consultant, Experienced Commercial Brewer​ | d 504.930.4462 (schedule a call)

    1600 Tchoupitoulas St New Orleans, LA 70130​ | p 855.953.8853


    • #3
      Do you have a length of choker line before the faucet. You should have a length of 1/4 inch tubing before going into the faucet. The length depends on the distance the run is along with the rise/fall of the line. I have talked to Micromatic before and they helped out, but they will need the info I mentioned above.

      Jim Lieb


      • #4
        Definitely try choking the line back, but in my personal experience this is too long of a draw to use a direct-draw setup reliably. Initial installation should have made use of either beer pumps or mixed gas to prevent a lot of the issues you are discussing. Separate regulators is obviously best, check valves at minimum. Without you are just averaging the head pressure over all your kegs to the same. Eventually they will be all carbed the same.

        Before spending $$ on a retrofit, try the 1/4” choker line. I think Foxx used to sell in-tube mixers that work well for this also. It’s the equivalent of stuffing some sanitized zip ties in your lines to restrict the flow.

        Flow control faucets are nice, but over priced IMHO. They will only allow a small amount of adjustment (but that is all you should need if doing things correct).


        • #5
          If the lines are 3/8" ID the whole way, you don't have enough restriction in the lines. What you do is this: set your CO2 pressure to maintain the right carbonation levels in the keg - about 12 psi at 38 F. Then you balance that pressure with enough restriction in the line to keep the CO2 in solution, and pour just fast enough to fill a pint in about 6-7 seconds. 3/8" hose only has about 0.2 psi restriction per foot, so you need a length of "choker hose" at the faucet end. 3/16" ID hose is the best, it has a restriction of 3 psi per foot. Also each foot of elevation difference between the middle of the keg and the faucet is 0.5 psi. You say the faucets are about 6 feet lower than the kegs if I am reading your post right. So the elevation change means you need an additional 3 psi of restriction plus the restriction needed for the keg pressure of 12 psi. 15 psi of restriction using 3/16" ID hose would be 5 feet of hose at the faucet end.
          Linus Hall
          Yazoo Brewing
          Nashville, TN


          • #6
            Thanks all I went ahead and added 5 feet of 3/16th choker line to all of the taps. Also I have decreased the temp of the chiller. I have a concern that the glycol may be going too slow however and warming up before reaching the end of the line and returning. Currently have a 1/3 hp pump, have thought of going to a 1/2 hp pump any ideas?