Weird problem just cropping up on one of my kegs. I recently tapped a blonde ale that I naturally carbed in the keg. Let it sit for almost 3 weeks, put it on roughly 7 psi to serve and everythings been great - until today.
I pulled a couple pints earlier and it poured fine, decent head no excessive foaming. But the last few have had TONS of foam. I didn't change anything, absolutely nothing has been touched or changed short of the amount of beer in the keg (still almost full).
I'm running a 5' picnic tap, and have had zero problem with the last keg and the first part of the current keg. I typically keep the pressure right between 5-7 psi for serving. I've already tried bleeding the pressure out of the keg and reapplying pressure but to no avail.
So what's up here?