A Leaky Keg Valve

Losing CO2 from your tank and can’t figure out why? It might be a faulty keg valve. We here at KegWorks encountered this very rare and puzzling problem last week.

A partial CO2 tank that had dispensed many kegs over the last year ran out late last Thursday. I chalked this up to the tank emptying normally from dispensing many an afternoon brew. I replaced the 5lb tank with a full one, and we were back in beer on Friday. On Monday the tank was empty again. I then knew we had a leak somewhere in the draft system.

After getting another full 5lb CO2 tank hooked up, I turned everything on as if I was going to dispense beer and performed a simple leak test on the CO2 side of the system. This consisted of grabbing an extremely soapy dish sponge from the office sink and swabbing every airside connection from the tank to the coupler with the soapy foam, looking for a bubble-generating leak. Much to my surprise, I did not find one until I swabbed the base of the coupler while it was fully engaged to the keg and noticed bubbles generating out from the edge of the keg flange. Bubbles emanating from the is area could be the result of a bad coupler body seal, but after inspecting the seal for cuts or gouges that could cause such a leak, I found none. So I decided to test the keg valve itself without the coupler attached. I swabbed the valve with a large amount of soap foam and saw bubbles generating from between the keg flange and the keg valve. Mystery solved! Our system was sound, but the keg itself was leaking CO2 due to a bad seal between the keg valve and the keg body.

Leaky Keg Valve

I called our great local brewery, Flying Bison Brewery, where we get most of our office beer from, explained the issue and was told to bring the keg back to exchange if for a full one. The next day I went to the brewery, where a very apologetic brewer made the exchange and we were back in beer. So, if you ever start losing C02, check your system thoroughly for leaks, including the keg.



  • Hannah May 27, 2009 @ 10:31am

    Wow Pete, great sleuthing! And thanks for passing on the knowledge – I’m sure many others out there have had a similar problem and never even knew.

  • david July 1, 2009 @ 5:28pm

    i have a faulty keg myself and had to check the diaphragm of the regulator, which has the screw into it. I cleaned it and it still leaked c02. Now its time to swap out my keg at the liquor store.

  • Hannah July 2, 2009 @ 7:56am

    David – yeppers, and hopefully the store you bought it from will compensate you, since it wasn’t your fault your keg was leaky! Good luck!

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