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Problem with dispensing from serving tanks

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  • Problem with dispensing from serving tanks

    I've recently opened a brewery where our primary focus is our tasting room that is supplied from serving tanks direct to our taps. I've run breweries before but this is my first experience with serving tanks and there is not a lot of local breweries using this system so its been difficult to get info. Basically when we pour from our taps it will pour fine for awhile and then surge with foam, which makes me think perhaps the co2 is "breaking out" like when your psi isn't high enough. What I don't understand is we use beer pumps to supply the beer to the taps. Head pressure on the tanks is individually set (with CO2) for equilibrium based on the particular beer temp and co2 volumes. Talking to my draughtline guy he says this shouldn't effect the beer dispense as this just maintains the carbonation, it is the pumps that supply the beer to the taps, but he is stumped as to the problem. The pumps are run by our air compressor (this air doesn't come into contact with the beer) and I'm wondering if the pressure the pumps supply or the length of the lines could be wrong. Not sure if a counter-pressure system of filling growlers would help as it wouldn't be practical with our setup and the problem occurs pouring pints as well anyways. Has anyone experienced anything similar to this or have any insight to a solution? If it is a problem with the pressure the pumps are running at I can start researching how to adjust them but wanted to ask Probrewer first.


  • #2
    I also don't believe it is from an overcarbonation issue. We carb most beers to 2.7 volumes but when we keg beers off to move to our long lines to free up a serving tank for a new beer the kegs universally pour fine from the long lines. Obviously there will be some co2 loss from kegging, but the difference in the dispense quality is so dramatic I can't see it strictly being a carbonation problem. Generally however, the more carbonated the beer, the greater the issue.


    • #3
      I am assuming these are jacketed serving tanks. I have several customers who serve direct from tanks and they are piped from the tank into the cold room to the beer pump and back to the tap in a glycol cooled line. They rack off to kegs at the end of the tank and have connections in the cold room that run the kegs through the same beer pump. Does this should like your set up? You can also find a very complete draft beer guide by micro matic here on PB.


      • #4
        Johnny--There are lots of variables involved in a draught system, and you've covered some of them.

        Are your lines continuously chilled and insulated? A hot point in a line will cause just what you describe. The faucets should be cold enough to sweat. If your lines are entirely inside a cooler, you need a shadowbox through the cooler wall with a small blower to keep the faucets and shanks chilled.

        What dia. are the lines to the pumps? Using 3/8" line from keg/tank to pump, I still have to add a little bit of pressure above EQ to keep the beer from breaking here. I do this by eye--have someone pour a pitcher while I watch the line for breaking, then turn the reg up until it stays clear beer.

        If your beer pumps are lowering the pressure in the delivery lines below EQ, you'll have breakout.

        Are you balancing your lines from the pumps to the faucets? Most beer pumps produce, IIRC, 15-25 psi of pressure, depending on drive air pressure. You need to balance that with choker lines.

        How big are your CO2 lines/regs to the serving tanks? If you're drawing beer faster than the CO2 can make-up, you're losing head pressure and push to the beer pumps. A common problem is too many kegs/tanks per 2ndary regulator. I limit each 2ndary to no more than 4 kegs or one serving tank, with a short 1/2" line from reg to vessel.

        Does the problem get worse on a low tank? Don't forget the hydraulic head pressure of the height of the beer in the tank, which decreases as the tank empties.

        Something that will cause this episodic foaming that is hard to find is a restriction in the line that widens afterwards. This causes a venturi effect, with lower pressure downstream of the restriction--low pressure=breakout. I had this happen with some undersized barb/barb hose couplers once. Drove me nuts until I figured it out. A kink or tight bend in a beer line will do this, too.

        DL the Draught Beer Quality manual for a great guide to beer delivery systems and balancing lines. I've probably neglected a half dozen factors here.
        Last edited by TGTimm; 01-24-2018, 03:31 PM.
        Timm Turrentine

        Terminal Gravity Brewing,
        Enterprise. Oregon.


        • #5
          Yes tanks are jacketed, which let's me set the individual temp for the beers (with head pressure adjusted for equilibrium based on carbonation). We don't go to our cold room and back with our lines as that would be a long run. The lines run to the pumps which are in a small fridge under the bar, and from there to the taps. All lines are insulated and glycol cooled.

          Lines are continuously chilled in a glycol trunk line to the pumps and then a choker to the taps (if I remember my terminology right from my draught line install days). Before I became a brewer I used to work for the guy who installed our whole dispensing system, he is very good.

          Can't remember the diameter of the lines, but I believe 3/8' or 5/16", but will check that.

          We have a separate regulator for each serving tank. I have wondered about the ability of the regulator to keep up but talking to my front manager there seems to be no connection between volume of service and amount of foaming issues.

          There seems to be no correlation between volume in the tank and issues. The reason I went with beer pumps was to avoid the issues related to varying amounts of hydrostatic pressure. I have seen breweries try to use serving tanks with head pressure alone and it was always causing big problems.

          I will talk to my guy about the possibilty of a tight bend in the line being the issue. The serving line that attaches to the bottom of the tank via triclamp takes a sharp u turn as the taps are on the other side of the wall behind the tanks, so maybe this is the problem?

          Other than this I can only think it is to do with the delivery pressure of the pumps, so I'll start looking into that.

          Thanks for the feedback


          • #6
            Any update?

            Any update on a solution for your problem.

            We are using 10 bbl serving tanks and have been running into problems with CO2 gas pockets.

            I think that our problem may be that we don’t have the line running from the tanks to our beer pump glycol insulated-right now we just have insulation surrounding it. I guess what’s happening is that as it sits in the line, it warms up to ambient temp and has CO2 come out of solution. Eventually that CO2 pocket reaches our FOB which is in our walkin and drops the ball and flow to the taps stop. We then have to purge the FOB of the CO2 and then beer flow resumes.

            I’m thinking I need to extend the glycol to each 8 foot hose connection to the serving tank outlet.
            I’m hoping that will fix the problem.

            Thanks guys.


            • #7
              If you are using a jacketed BBT then you need to run the beer through an insulated python into you cold room to a beer pump with a FOB and coupler hook up. This will allow a quality pour and be set up for the couple of kegs you rack from the BBT to pour during your next clean and transfer.


              • #8
                We have the same issue. I will never use jacketed serving tanks again! The 1.5" line at the bottom of the tank is not glycol chilled, a few pints sit in there for maybe 20 minutes, warms up and foams. I can tell its breaking out as the sightglass will have gas bubbles coming up its length. Beer pumps make sure everything is pressurized but i found that anything above 8psi pure co2 and my beer overcarbonates in a week. Just this week have finally enacted my plan to install a nitro blender so i can put 20psi 25%CO2/75%N on the tanks(to start) so the pressure will keep the breakout to a minimum.

                Curious to see if the nitro blend at 20psi will let CO2 gas precipitate out, if ill have to switch to a different blend or what!

                Wish me luck!