[cyclejim]

I have 1 keg that dispenses nothing but foam, while my other kegs are fine.  I've tried a number of things but I can't figure out the cause.

I brewed 10 gallons that I put into 2 kegs and force carbonated.  When I first tapped this one it dispensed foam.  I was taking beer to an event and in a hurry and just switched the tap to the other keg and it dispensed fine.  The first keg is gone and I tapped this one again and it is still dispensing foam.  I have 3 other kegs on the same regulator that are all fine.   

When I pull the handle, the beer line fills with foam on its way to the tap.  I thought maybe it's a pickup tube or poppet valve problem, so I swapped them from a known good keg with no change.  I changed to a different tap with the same result.  So I have changed everything in the dispensing line from the bottom on the keg to the glass and the problem persists. 

I'm dispensing at 12 psi through 5 feet of 3/16" tubing to a Perlick faucet.  This setup works for my other kegs with minimal foam.  The foam appearing directly out of the keg I think is the key, but I don't know what to do about it.

Any ideas on what the cause might be?  Did I do something with force carbonating this keg that is sticking around to cause this?  I've been kegging for years and while I won't claim to be an expert, I've never had this problem before.  I have a second regulator for carbonating and I force carbonate at a higher pressure and may have been distracted by drinking other beers and left this one on longer, but I'm not sure.  Any suggestions are appreciated.

[Bob357]

Restriction in the dip tube or poppet can cause excessive foam. If you've tried everything else, pull the out post off and check everything on that end.

[cyclejim]

Thanks for the suggestion Bob357.  I posted this on another site as well and got an answer there:  over carbonated

I had tried replacing the dip tube, poppet, post and eventually the dip tube o-ring, all to no avail.  Someone suggested over carbonation and linked to a method of fixing that problem quickly.  Essentially, I pulled the keg out of the fridge, put a dispensing line with picnic tap on, turned it upside down and purged the pressure through the picnic tap.  Next was turn back over and try dispensing a beer.  About 3 iterations of that resulted in a pretty good pour.

It looks like I over carbonated but wasn't sure that was the problem and had no idea how to fix it. 

[ynotbrusum]

Another solution is to pull the PRV repeatedly over a few minutes, then pour a couple pitchers and then repeat, as necessary until it pours beer more than foam.

[Slowbrew]

Been there many times.  Typically with my saison.  My kegs have PRVs so I generally release pressure through the PRV until it foams, wait a few hours or more and do it again.  When the pitch of the hissing gas drops into a more normal range I start pouring beer with any pressure on the gas-in line.  It can take a few days but works.

Paul

[jeffy]

That whole thing with the picnic tap and turning the keg upside down is over thinking.  As the two posts above recommend, the same thing can be done with the pressure relief valve.  If it is a pin lock keg (no prv) then pressing the gas valve poppet does the same thing.

[goose]

Thanks for the suggestion Bob357.  I posted this on another site as well and got an answer there:  over carbonated

I had tried replacing the dip tube, poppet, post and eventually the dip tube o-ring, all to no avail.  Someone suggested over carbonation and linked to a method of fixing that problem quickly.  Essentially, I pulled the keg out of the fridge, put a dispensing line with picnic tap on, turned it upside down and purged the pressure through the picnic tap.  Next was turn back over and try dispensing a beer.  About 3 iterations of that resulted in a pretty good pour.

It looks like I over carbonated but wasn't sure that was the problem and had no idea how to fix it.

Just read your poost and also thought that overcarbonation was the problem.  As Jeffy and others have mentioned using the PRV on the keg lid to relieve the pressure several times is the easiest way to bleed off keg pressure.  I have done this, let the beer set for 24 hours and repeated the bleed-off.

Another thing I learned during my pro brewer gig, when we accidentally overcarbonated a beer in the bright tank, was to take a rubber mallet and whack on the side of the bright to get the carbonation to come out of the beer (along the lines of what happens when you shake or drop a can of commerecial beer).  Obviously with a corny, you want to tap the side of it gently so you don't dent the keg then bleed off the pressure through the PRV.  This will bring excessive carbonation out of the beer a bit faster.

[denny]

Sounds like the classic sign of overcarbing to me, too