foaming

[Crackin]

Every once in a while, I get a keg that foams. It pours fine, then a portion of air / foam, comes out, then it pours fine, then more foam, etc. It is as if there is air mixing in somewhere, although I know that is not really possible. All the lines are inside the fridge, so the beer is not warming up as it travels. Sometimes I can see air in the beer line, and CO2 comes out of solution in the line. Is it just over carbed? Does not appear to be.

This is not a question about balancing your system, etc. I know that stuff.

Any ideas?

[ApresSkiBrewer]

If you see CO2 break out in your beer line, your applied pressure to the keg is below that of the CO2 saturation pressure of your beer. The CO2 will break out, and find the high spots in your line (with a 3/16ths jumper, there might be a curl that will provide 1, 2 or maybe 3 high spots...) the first one behind the shank, and then somewhere else along the line, where the line goes up... back down, and up again. As the beer pushes through these spots, it won't pour clear from the faucet.

Do the flashlight test to find the approx. actual applied pressure you need to the keg to maintain balance.... if this is homebrew and you force carbed the quick way, there is a good chance you did over carb a bit, and are now setting your regulator to the 'ideal' pressure based off of the Volumes of CO2 you were targeting.

Flashlight test is as follows. Only applies to draft systems pushed with 100% co2.

Directly above the coupler (line out ball lock in this case) use a flashlight shining from behind the line to see if you see bubbles rising (small bubbles, not large mechanical bubbles... the larger ones tend to break back into solution in the line and exposer to line resistance, while the small bubbles are breaking out of solution, and will be what tends to collect in the line high spots/behind the shank) - If you do, turn your regulator up a PSI or two... pour from the faucet for a second to clear the line (3/16ths ID only holds 1/6th of an ounce of beer - so even a 6 foot jumper will only have 1 ounce in the line.)

After the pour, use your flashlight to look for small bubbles on the rise out of the keg again. Continue the above process to turn up your applied pressure until you see no bubbles rising at that point.

Now, let's say your all the way up to 16 PSI and your kegorator is at 38ºF... but you were targeting 2.5 vols.... you're obviously overcarbonated. Disconnect the keg, and vent it a few days to bring the carbonation down and back into the appropriate range.


There could be other things going on to cause intermittent foaming at the faucet... to trouble shoot that, post specific details about your keg setup/temps/line lenths and ID's, etc. I'm assuming a converted direct draw kegorator is what you've got going on. Also, what is your most common carb'ing method, and do you ever dry hop or anything like that in the keg?

I just finished the micromatic dispense institute course on Thurs... so we'll be able to figure this out.

[Crackin]

I think you hit the nail on the head. I don't force carb, but I do have 5 kegs in the fridge, and only 2 CO2 lines. This means that I am swapping the CO2 from keg to keg, over time. To make things worse, I am certain that the fridge keeps the kegs cold, but the temperature of the beer fluctuates a few degrees either way. I also might have one CO2 line a pound or so above another, so when swapping CO2 lines around, this doesn't help.

I suppose if I had the CO2 line with 14 pounds of pressure on a keg, and the beer was at 38 degrees (for a week), and then the beer warmed up to 39 degrees and I had swapped the CO2 line to the one with 13 pounds of pressure, I would end up with foaming.

Funny that the solution to the foaming problem will be solved by upping the pressure. This is the counter-intuitive part that I was not understanding.

I guess the solution is to get a CO2 manifold to keep all the kegs gassed up from the same regulator.

Thanks much. That makes perfect sense.