Just cracked open a Kolsch this weekend, and while I was mostly pleased, it has a little bit of a funky, musty flavor to it. It's not bad, really, but it's there, and it shouldn't be. I've had this problem before with a nut brown and a cream ale - those were undrinkable bad.
All I can figure is, maybe my fermentation temperature got too high? I've really not paid enough attention to that in the past. It should have been in the high 60s most of the time, but might have topped into the low 70s now and then.
Yeast was Safale-05. I like that one because it at least claims to have a really wide temperature range. But, like I said, my kolsch isn't as crisp and clean as I want it to be. Any thoughts or advice out there?