I was kegging a batch of Honey Brown yesterday and I noticed this white, bubbly, film sitting on the top of the beer. It wasn’t fuzzy or hairy, and it didn’t smell like mold. But it was white and slimey. Tasting the beer after getting into the keg I didn’t taste anything really bad, but there was maybe a bit of a stale flavor. I’ll taste it again in a few days after it carbonates a bit.
This is the first I’ve ever experienced this, anybody know what it is? Here is a picture:
That’s a wild yeast called Kahm yeast, it might be Diplodia. In looking further into things I found on the homebrew forums lots of photos of Kahm Pellicle, apparently a feature of many types of beer.
http://www.homebrewtalk.com/f127/pellicle-photo-collection-174033/
When I’ve had it on my beer it was usually when I got a little lax in sterilizing and leaving things open to the air too long.