Kegging/carbing in Same kegs

[ChicagoJack]

So I work at a tiny little nanobrewery and we don't have a budget for brite tanks, so we carb in the kegs. Every so often we get a keg that is nothing but foam, but the beer isn't overcarbonated. My first thought was that the line itself that was on had a leak in it, but if I switch to a keg that pour fine on the same line, everything is cool. What's even weirder is that we've had kegs that went from pouring fine, to nothing but foam, while they weren't even on gas.

 

[porterpounder]

Only things I can think of is that you're somehow losing head pressure in the keg from the tank which will cause foaming, the temp of the keg is somehow rising and creating release of gas, or the kegs aren't fully clean and maybe some gunk on the side of the keg is dissolving when the beer gets to the level and it's creating nucleation points for the CO2 to come out of solution and create foam.

 

[gnef]

This reminds me of when stuff gets caught in the poppet or disconnect causing a restriction and forcing CO2 out of solution. This happened to me mostly when I was dry hopping, and small hop debri would get caught and cause the problems, but I've also had excessive trub left in kegs that caused problems like this, and even clogged my liquid post completely.