I tried to tap my cream ale last weekend and my beverage line clogged. I put another line on it and also clogged. I pulled the dip tub and valve and they looked clean. Both lines looked like it had yeast gunk in them. Yep, gunk; let's keep it sciency! Not wanting to think about it, I drank saison for a week. (How many homebrewing problems get solved this way?) Today, after some fruitless tinkering, I did what I probably should have done in the first place: cranked the pressure up and it pushed the yeast gunk out of the way. There is always some yeast trub that makes it to the keg and the first few draws are yeast, but I can't say I have had this experience, where yeast trub clogs my tap lines. Is this more common than I think? I normally keep about 8-10 psi but was up over 30 to push the trub out of the two clogged lines.