Foaming on 1 line of 3 line system

[Doug Chapiewsky]

I have 3 lines in a glycol pump system and appear to have problems with one of the lines. The keg pours great and then suddenly goes to complete foam. It never recovers no matter what I try. The other two lines seem balanced and work fine. When I switch the line to another keg, sometimes it works fine. It appears this line will "corrupt" a keg and then I can't get rid of the foam. I've already replaced all taps. Do I have a bad coupler? What is the proper way to clean a coupler? Any ideas? Thanks.

[Scott Zuhse]

Doug, we need additional info such as gas used and at what pressure, temperature of the beer, elevation, type of beer, system length, etc. The more we know the easier it will be to solve problem.

Scott Zuhse, Instructor Micro Matic Dispense Institute

[Doug Chapiewsky]

Using CO2 gas at approx. 20psi running 40 ft with a rise of approx 15 feet. I keep the beer around 38 degrees. I usually have Sierra Nevada and a couple of micro brews tapped.
When dissassembling the keg couplers, I noticed there is a small, plastic insert in the CO2 line that appears to reduce gas flow into the coupler. Can this cause issues? Thanks.

[Scott Zuhse]

This small piece you are referring to is a back flow preventor. Leave this in the system. With the info provided, it is probable that you are overcarbonating the beer. What line sizes and lengths are you using?

Scott Zuhse, Instructor Micro Matic Dispense Institute

[Doug Chapiewsky]

I'm running about 35 feet of standard beer supply line and about 7 feet of constriction hose to the taps. It's frustrating because it often works perfectly for dozens of pints, and then turns to immediate, total foam. Whenever I fiddle with it, including cleaning, it often goes into a foaming mode. Do you know what steps I can take to reduce my problems? Do I have to move the kegs closer to the taps? Less constriction hose? I've dissassembled the coupler and cleaned everything thoroughly. I've turned the CO2 way down to 10-12psi. Temperature is constant at around 36-38 in cooler and out of tap.

[Doug Chapiewsky]

One more point, every time I go "foamy", the foam comes out in gentle "spurts" as if there's gas directly in the supply. I've oiled the O rings in the couplers and thoroughly cleaned the faucets, even put in brand new faucets.

[Scott Zuhse]

Doug, you have over-carbonated the beer due to the 20 PSIG. Once you have over-carbonated the product, you have basically lost the last 1/4 of the keg due to the beer is like champagne - full of gas!. Major concern is the 15' vertical rise (vertical distance between the bottom of the keg and the faucet?)and dispensing 40'. It is very difficult to accomplish this with just CO2. A tendency is to increase the pressure to compensate for the pressure drops in the system. This can not be accomplished.

The pressure using CO2 must always be contingent on exact temperature of the beer, carbonation recipe level of the product and elevation. Never use the CO2 to control flow speed or to compensate for temperature fluctuations downstream from the keg or for high vertical lifts and long runs.

If the standard 35' trunk-line is 3/8" I.D. barrier (vinyl/poly???) and the seven feet of constrictor (choker) is 3/16" I.D. vinyl, with the 15' vertical rise and misc. hardware you have approx. 30 PSI of restriction/back-pressure in the system. You would have to push the beer with 30 PSIG to acquire a 128 oz/min flow.

My immediate recommendation would be to invest in a blender and push the beer with 60% CO2/40% Nitrogen at about 25-28 PSIG. Or, move the kegs closer to the faucet.


Scott Zuhse, Instructor Micro Matic Dispense Institute

[Doug Chapiewsky]

Thanks for the great information. When you say "blender" do you mean simply switching out the CO2 to the 60/40 "beer mix" of CO2 & Nitrogen? Do I need any other special equipment in the system?

[Doug Chapiewsky]

I just found the blender on your web site. Is this a better path than buying a blended tank? I'm finding suppliers with a 75/25 mix. Is 60/40 the best? Also, are my kegs now a problem if they're over carbonated?

[Doug Chapiewsky]

Scott, Sorry to inundate you but I just talked to the local bar supplier here in the Vail, Colorado valley and he said every bar runs with a 70% nitrogen/30% CO2 mix. He's surprised I can pour any beer without foam. Thoughts? He's confident this mix will address my foaming problem.

[Scott Zuhse]

Doug,
This suppier is incorrect. Every bar that does utilize this product is allowing their product to become flat. The best practice would be to dispense with the correct ratio of CO2 to Nitrogen. A 60% CO2/40% Nitrogen is a great product for maintaining the recipe of gas in the beer. I will be in Beaver Creek on Thursday and can meet with you if you have time. Call this number (866 327-4159)and ask for my cell number and contact me so that we can discuss further.

Scott Zuhse, Instructor Micro Matic Dispense Institute