I have a two-tap kegerator which I use to dispense commercial 5-gallon kegs. My lines are about 3 feet long1 and I keep my pressure at 10psi and my temperature relatively cold.
Whenever I draw from the tap, I get beer immediately. It looks like a great pour. But always, about half a second after opening the valve, the beer coming out turns foamy for about a second and then returns to normal. This produces enough head that my glass always ends up being half foam. If I have a pitcher that I'm filling, or if I have two glasses and I can run the pour from one to the other, the rest of the pour will be excellent with no foam.
Why does this happen? I have always had this problem with my setup. I used to keep my pressure at 15psi and dropped it to 10psi (and I like it - I think I'll end up on 11-12psi). But that hasn't helped this problem at all. I also tried lowering the temperature on the kegerator. This also hasn't helped. These are things that I feel are just general tips to try to reduce foam. But I feel like there's something specifically wrong with my setup where air is getting in the line somehow.
This problem happens on both taps. This problem happens no matter what keg I hook up. I have used Kegcraft kegs from Half Acre Chicago, as well as commercial kegs from various craft brewers available in Chicago. They all have the problem. This problem has persisted across CO2 tanks as well.
I'm using Perlick 525SS tap handles. Am I missing an O-ring somewhere? How can I test this? I'm sick of having this problem!
1Edit: I estimated three feet when I wrote the question. The line is perhaps actually four, maybe four and a half feet. They came as part of a kit, and I did not cut them. I don't know exactly how long they are, but they are sufficient length to change kegs, clean, and otherwise maintain the set.