Foamy keg problem

[Westcoastrocks]

So recently most of the kegs start to foam like mad when there is about a gallon left. Can't seem to figure out why it only does it then. Anyone run into this problem before?

[kugeman]

Sounds like your head pressure is too high. What temp are the kegs being served at & what is the pressure you're pushing them with?

[einhorn]

I agree with Hutch: only 3 unknowns on this equation (and 99% of such problems) being temperature, head pressure and line size.

[Westcoastrocks]

The walk in freezer says 34° I am not sure how much I loose going through the wall(chilled with recirc cold air) and up the towers. But it come out pretty cold.

I am serving the beers at 10 psi. There is about 8' of the standard beer line (forget how big 3/8 maybe) with 6' of a choker line.

[kugeman]

Well, 34 F at 10 psi would put you at 2.58 vols of dissolved CO2. That doesn't sound crazy high. However it really depends on what your draft system was designed to pour. The fact that your kegs consistently pour fine until they get low tells me that your kegs are becoming over-carbonated during the time they are on tap. How does the beer taste when the kegs get low and start becoming foamy?

Usually a keg becoming over-carbonated while on tap happens because there's too much head pressure for the temperature of the beer, so as the beer level of the keg gets lower it absorbs more and more CO2 until its too carbonated for the draft system to pour correctly.

You'll need to 1)make sure that your cooler is actually at 34 degrees (not 32, that would make a big difference) and 2)that your regulators are reading correctly at 10 psi (not 12, also a big difference), and 3)what the resistance of your draft system actually is. The Brewer's Association draft manual (available on their website) can give you the numbers needed to calculate what the resistance of your draft lines are, and thus what the head pressure needed to pour beer properly is. You can then adjust your temp and pressure to properly pour your beer without the kegs becoming over or under carbonated as you go along.

[Westcoastrocks]

I will start paying attention to what you said. I have calculated the resistance and technically it's was over what is needed. I tried having lower resistance but all the beers would foam. I kept adding resistance till they poured perfectly and they did for about 6 months. They still do just not at the end.

[einhorn]

How long, in general, is a keg on tap?

[Westcoastrocks]

Some kegs it could be 2 weeks. Some 1-2days.