Help! Why is CO2 coming out of solution in my beer lines?

[GnvBrewer80]

Hey everyone,
I've tried to do my homework on this one by searching the HomeBrewTalk forum threads. I've checked the usual suspects (e.g., loose connections, lubricating O-rings, etc). I am running a computer fan at the top of my chest freezer to try and maintain consistent air temperatures. Based on a thermometer, the bottom of the freezer is sitting at 35F, while the top of the freezer near the faucets is sitting at 38F. Beer comes out of the faucet at about 41F.

One of my beer lines appears to get a 5" CO2 bubble at the end of the beer line near the back of the faucet approximately 18-24 hours after pouring a pint. This current keg is full (Munich Helles that I just kegged two weeks ago). I see NO small bubbles rising to the top of the beer line (e.g., towards the faucet and tap) immediately after pouring a pint. Still no bubbles after 4-6 hours. But, boom it's there the next morning. The other faucet has no problems with any CO2 bubbles.

I have broken down the keg, replaced the O-rings on the gas/beverage dip tubes and lubricated them with keg lube. I have also lubricated the poppits for both the gas in and liquid out connections. I have also checked and tightened the worm clamps where the beverage line connects to the liquid out quick connect and where the line meets the beer shank.

Next step is to switch the kegs (I have two full right now) to see if it is a keg problem or faucet problem.

Any ideas or things that I'm missing? Maybe I should get comfortable with losing that 2-3oz of beer whenever I need to draw my first pint?

Thanks!
Alex

 

[day_trippr]

Don't settle for wasted beer, tune up your dispensing system. Does your fan run continuously or intermittently? Favor the former for holding more uniform top/bottom temperature. What differential are you using - and where is the probe located. Imo, the tighter the better, and close-coupling probe to fullest keg works best. What size/length beer line? 3/16" is best for most situations, and 10' will put you in the ball park wrt resisting CO2 break-out...

Cheers!

 

[GnvBrewer80]

Thanks for the reply.

The computer fan runs all the time since I agree with you that I want more uniform temperatures. I am running an analog Johnson Control temperature controller. The probe is sitting in the back right corner of the chest freezer, about 4-5 inches from the bottom and about 1/5" from the back wall.

I'm sorry that I forgot to include beer line information; I run 3/16" thick-walled beverage line with 9' of line. Would an extra 1' of line really make a huge difference? My beers are set between 11-13 PSI (mostly set at 12 and forget it).

Alex

 

[GnvBrewer80]

Opps, I meant 1.5" from the back wall!

 

[day_trippr]

I would expect going from 9 to 10' would provide a virtually indistinguishable difference, as long as you're dealing with moderate carbonation levels and hold the beer in the range you described. That said, you may well be sitting right on the edge of holding things together, and the least provocation results in CO2 break-out.

Swapping the beer lines between kegs could be illuminating, one never knows. I'd definitely give that a try just to see what happens.

[fwiw, my rule of thumb is one foot per psi carbing/serving pressure given a keg temperature centered around 36F (thus for the same carbonation level a warmer keezer would need higher pressure hence longer lines). Rather than adjust line lengths for differently-carbed beers, I stick epoxy mixing sticks down the bore of the keg diptube to accomplish the same adjustment...]

Cheers!

 

[GnvBrewer80]

Yeah, I'll swap the beer lines and see if I still get the breakout. I just pulled a pint and checked the temperature with a ThermaPen. Beer is about 43F. A little wamer than I expected and maybe partly to explain the breakout in CO2.

I'm going to dial down my controller two degrees, which should set everything a bit closer to that 36F keg temperature you referenced above. I have found that the offset on my analog controller is about 4 degrees (eg., for 36F keg I will set the controller at 32F). I assume that is a normal offset compared to others' experiences?

Thanks!

 

[JuanMoore]

There are exactly three possible causes. One, the serving pressure is lower than the pressure that corresponds to the carbonation level of the beer at your serving temp. This by far the most common cause of this issue. Second, your computer fan isn't doing it's job of keeping temps even. There needs to be a very large temp differential between the beer in the keg and the beer in the line for this to be the cause though, more than 3°. The third and least likely cause is a bad liquid side diptube o-ring letting gas into the beer line. This typically causes pockets of gas to form as it's poured rather than over a long period of time after a pour though.

 

[DrunkleJon]

One, the serving pressure is lower than the pressure that corresponds to the carbonation level of the beer at your serving temp.

This, it is usually this.

 

[GnvBrewer80]

JuanMoore,
You could be correct in your first suggestion. The Munich Helles was kegged two weeks ago and I use the set and forget method to reach serving carbonation. It is set at 12.25 PSI and may not be there quite yet. If this is the cause, I assume the solution is simply to wait another week (3 weeks total at 12.25 PSI) and see if it is fixed.

I did swap the beer lines and there was NO CO2 breakout in the beer line from the other keg (an American Amber that has been kegged for 1.5 months). No breakdown from this keg, which I know is carbed up at 12 PSI, suggests it had something to do with the newer, and still carbonating, keg of Helles.

I also dialed down the temperature 2 degrees, which helped the liquid hold more gas.

Thanks!