…I think I just found one. I assume that at one point I filled a keg high enough that the inlet stem reached down to the beer, then pulled some into the line while I tweaked pressure between carbing and serving. Replaced the blue line with a clear one, hopefully will be good to go from here on out!
There are actually tiny beer line backflow check valves available that you can install to help avoid this condition. LHBS should have them.
Check valves are a good idea but I have had them stick (open or closed).
The ones I have are pretty cheaply made, which is likely a factor, but I haven’t had much luck cleaning them once they get stuck. I have had to replace 2 out of 4 over the years.
The problem was caused by over carbonated (and a bit over filled) kegs pushing beer back up the gas line. The old brewer guy didn’t notice it right away. :( He never seems to learn. 8)
Paul
Great input Paul, thanks.
Oh, I learned… unfortunately, the hard way :-[
But how often are lessons learned the easy way? ;D