lemon flavor after kegging This is probably a dumb thing to say, but if it only appeared after kegging, check the keg. I had a porter that I kegged in a corny that I swear I scoured, sanitized, and changed the O-rings on, but it ended up introducing a bizarre, artificial-citrus flavor. My only theory is that somehow the orange soda that the corny had contained at some point had seeped into the metals or something.