I brewed a PM version of BM's Centennial Blonde, and pitched Nottingham @ 64-65. It sat for 3 weeks in primary and it tasted great, I sampled it a few times. After the 3 weeks i dry hopped with 1/2oz of cascade pellet right into primary. 2 days later i pulled out the bucket along with 2 others for a friend to taste test. Upon removing the lid i could tell something was wrong, the smell was harsh, like grain alcohol/acetone and had the same taste. FG did not move was at stable 1.011 just like after the first week. Oddly though there was a clear layer of liquid about a 1/4" thick (presumably alcohol) on top of the beer, some of the hops were still in suspension so it was quite easy to see them floating below this layer. I'm at a loss at what could cause this, Fusel would have most likely formed during the initial fermentation and i don't think it would of gone undetected for weeks. Has anyone seen anything like this? Thanks