CO2 Buildup in Keg Beverage Line

Lately, I've been having up to a foot of CO2 (hopefully) building up in the beverage line causing it to spurt and foam excessively when dispensed. The beer is at 38*F and 12lbs of pressure which should give 2.57 volumes of CO2. The dispense line is 3/16" I.D. and 7' long to a cobra tap that is opened fully when dispensing. About a week ago beer leaked out of the barbed swivel nut connection to the ball lock connector. I tightened it up firmly and cleaned up the mess.

What is going on?
Thanks!

I'd venture that your beer line is too short. I run the exact same pressure and temp as you, but have 10 foot lines and the pour is perfect through a black cobra-style tap. I'm no veteran, I just know what works for me...and the only difference between your setup and mine is the line length. Hope this helps!

the 10'line seems to be the cure all for this kind of problem. well...i hope it does. my friend's dad asked me the same question. i gave him 10' of line and said put that on instead of the short line he was using. i hope it fixed it for him.

You could test the above theory by dropping the pressure on the keg until the pour is about right. Once you find the right pressure for the pour, leave the keg a day and see if CO2 builds up in the line like you described. Assuming that works, go get a longer beer line. One thing I was thinking about is whether the line could be warmer than the beer. Any way that is the case? I can't imagine why, but everyone's setup is a bit different. Maybe the light in the fridge is staying on?

I would venture a guess that you have a loose connection. I have seen this before and unfortunately its not CO2, its air. Check your connections, esp your tap. Bad connections plagued a friend of mine until he just bought all new connections. Hope this helps.

Ok, I did some testing to verify the problem. It arose because the beer was at a higher psi for several days then turned down to a lower psi causing CO2 to come out of solution. The problem goes away after dissolved CO2 and pressure come to an equilibrium either from letting it off gas or turning the pressure back to what it was previously.

I imagine others in the future will also have this happen so I hope they stumble across this thread and it helps. Thanks everyone for your replies.

The CO2 in the line is most likely from the tubing being a bit warmer than the beer in the keg. Cold beer runs up into the line when you pour and them warms up 1-3 degrees which causes the CO2 to come out of solution. One thing that helps with this is to run a small computer fan inside to keep the air circulating. Everything tends to be the same temp then.