Foam Troubleshooting

5lb CO2 cylinder
Single regulator set @ 10PSI
Tee w/ lines going to 2 Pin-lock kegs
Loosely coiled beverage tubing
Picnic taps
Entire setup in the fridge ~ 40°F
Everything is equivalent between the 2 kegs

For my last several batches of beer, one keg pours beautifully, the other fills my cup with foam. As the beer is dispensing into the glass, it alternates between liquid beer and foamy beer. It looks like the keg’s about to blow and so it’s sucking some air up along with the beer, except that the keg is mostly full.

Any suggestions?

how long are the beverage lines? Should be at least 6’ on each.

I’ve had this happen many times before. The one keg which alternates between foam and beer was not fully fermented (or has a slight infection) causing the beer to start fermenting again. This causes it to create more carbonation and thus be very over carbonated. You need to remove it from the CO2 for a few days and vent 4-5 times per day until the keg is nearly flat. Then hook back up and it should be good to go.

It’s been a few years, but I recall maybe 10-12’ each. I did all the calculations at the time.

With the way I’ve got everything plumbed, it seems both kegs should be at the same pressure and that any additional pressure should be vented through my regulator. However, I will give this a try. I can’t rule out an infection, and when I tried force carbing by starting with a higher pressure and dropping it over a few days, I can’t guarantee I didn’t over-carb it.

Thanks for your responses.

Another possibility is some type of blockage in either the dip tube or the beer line of the foamy keg. If you have something partially obstructing the flow that can cause what you’re experiencing, similar to if you were to only open the tap half way.

Blockage possible but doubtful especially after OP describes carb method.

Check for a crack near the top of the dip tube for the keg that is foaming.

Also, basic troubleshooting technique: if you swap the two picnic, does the foaming follow the tap or does it stay with the keg?

I think it probably was just overcarbed. Last weekend, I had to make room in the fridge for a keg from my bro-in-law, also a brewer, who came in town for a wedding and brewed a batch for said wedding. Long story short, my problem keg spent a couple days at room temperature, unpressurized. Now that it’s back in the fridge, chilled, and under pressure, it’s serving perfectly.

I’ll be careful about overcarbonating in the future. I’m just surprised that over weeks of use, the problem didn’t remedy itself.

I think it probably was just overcarbed. Last weekend, I had to make room in the fridge for a keg from my bro-in-law, also a brewer, who came in town for a wedding and brewed a batch for said wedding. Long story short, my problem keg spent a couple days at room temperature, unpressurized. Now that it’s back in the fridge, chilled, and under pressure, it’s serving perfectly.

I’ll be careful about overcarbonating in the future. I’m just surprised that over weeks of use, the problem didn’t remedy itself.[/quote]
Maybe it’s just me, but that doesn’t make sense. Taking the keg out of the fridge and removing the CO2 line shouldn’t do anything to remedy over pressurization. The keg is a closed system that gas can’t escape from unless you vent it. Simply changing warming the beer for a few days, then chilling it again shouldn’t change that.

But it could be you had some funky connection issue with the post, or it was overcarbed and would have corrected itself anyway around the same time even if you hadn’t removed it from the fridge.

I should have been more clear. When I said that it was unpressurized over those few days, I mean that I actually released the pressure when I pulled it out of the fridge and once or twice more after it warmed up.