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Foaming From Kegs but Not Brites

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  • Foaming From Kegs but Not Brites

    Is there any reason why kegs would require higher head pressure for serving when compared to brite tanks?

    We serve standard ~2.5 volume dissolved co2 beers directly from brites under 13psi and have no issues with foaming at the tap. Once those brites are low enough, we keg the rest off and serve the remainder from those kegs. However, for some reason we cannot serve those kegs under the same pressure - 13psi. They foam continually at the tap until the head pressure is increased to something like 18psi.

    We have a long draw and we also push upstairs from the basement. We have beer pumps and FOBs on every keg line. The differences between the tank and the keg line are the FOB and maybe 8 extra feet of 3/8" beer line. The run from the FOB to the pump varies, but is no more than 30 feet.

    I understand how to fix the problem, but it's a band aid. Slower selling brands are picking up more co2 while they sit under the increased pressure. I can't gather why serving one beer from two different vessels won't work under the same head pressure. I've tried bypassing the FOB, I've tried different brands of couplers, and I'm running out of ideas.

    Any help is much appreciated!

  • #2
    Just a few opinions here:

    13 psi is a little low. Bump it up to 15 psi or just a tiny fraction under. That should keep your ideal carbonation volume depending on your cold room temp.

    Speaking of which, what is the cold room temp, serving tank temp, and keg temp? What temp is the glycol loop running assuming you have jacketed serving tanks? Do you have glycol refrigerated beer lines? If so what is the temp of that glycol? If forced air long draw, what is the air return temp? What is the beer temp at the tap? from kegs at tap? from serving tank at tap?

    What pressure are the beer pumps operating at? line pressure? how is the flow? Are the beer pumps in the cooler and all parts of beer hose insulated or kept cold?

    What is the total length of the long draw? You may want to switch from 3/8" to 1/2" from tank/keg to pump. Eliminate fob on serving tanks.

    Slower brands should not be picking up excessive CO2 at only 13 psi, or even at 15 psi. Test the regulators and gauges with a proven gauge. Could be experiencing "regulator creep". Cheap (Economy) regulators and gauges are not accurate and usually perform unwanted pressure creep.
    Todd G Hicks
    BeerDenizen Brewing Services


    • #3
      Keep the run from the keg to the beer pump as short as possible. If you can keep it down to 6' or less of 3/8" line, you can push the beer to the pump with little more than EQ pressure at your storage temp.

      Most beer pumps (diaphragm type, gas-driven) produce ~15psi. Balance your lines after the pumps using this figure.

      Download the Draught Beer Quality Manual and read the part on balanced beer delivery systems. Read Dave Maheen's white paper on beer delivery online. Using beer pumps should greatly simplify building a truly balanced delivery system.

      Finally, make sure your CO2 regulators are capable of keeping up with high-draw situations. I finally traced a mystery foaming problem to this. We had 8 kegs fed from one secondary reg fed by 1/4" line. During the rush hours, whichever beer was pouring the most would get starved for pressure and foam badly. I'm building my new system to eliminate this problem. We will have three secondaries, fed by 1/2" line each, and feeding only 4 kegs/regulator. Due to the greater head space in a bright tank, this problem would be more apparent in kegs.
      Timm Turrentine

      Terminal Gravity Brewing,
      Enterprise. Oregon.


      • #4
        Seems to have been fixed

        Apologies for the delay, gents, I do appreciate the inputs and questions.

        All good questions, Todd. The thing that baffled me is that regardless of what the answers to all those questions are, they are the same answers and conditions for both kegs and brites, and there are never problems with the brites. The only variable I could think of is that we had what I call mobile FOBs. When we keg a brite off, we would leave those kegs in front of the brite the beer came from, and then couple the output of those kegs into the beer line normally used for the brite. We inserted those mobile FOBs between the sankey coupler and the TC connector for the beer line. Once I removed that mobile FOB and placed it on the output of the beer pump, the problem seemed to have resolved. At least for now.

        Unfortunately, it's a lot longer run from most of the brites to the beer pumps, so when an inserted keg dies, there's just a lot more line purging to do. Far more than 6 feet.

        Again, appreciate the help!