Recently, I had a batch of oatmeal stout that went horribly bad. It was an extract batch, and I didn't taste anything particularly alarming right out of the fermenter, during bottling. BUT...after a couple weeks in the bottle, every single bottle of my 5.5 gallon batch tasted very strongly of rubbing (isopropyl) alcohol. Completely undrinkable. I'm thinking oxidized, but everything I'm hearing is that oxidation turns a beer stale and/or other off-flavors (diacytle); not this thing I ended up with. Any thoughts as to what might have gone wrong? Thanks.
Probably too warm, but it's where I've been fermenting all along. My basement is a consistent 73F. English ale yeast for that one. Fermentation may have been slower than ideal, but shouldn't have gone south. I'm pretty sure I've used that yeast before, but I only recently started keeping notes.
You are most probably too high on your fermentation temp. The best and most impotent tool is for beer making "Beer Fermentation book" if you order this book make sure you read it.
I would imagine that you had too high of a fermentation temp. 73F would be at the high end for most, if not all, English strains, and since yeast activity can raise the temperature of fermenting beer, and since English strains tend to be pretty active, you may have been north of 80F during peak fermentation. So far as why you didn't detect it at bottling, not quite sure. Green beer isn't finished beer; I've had batches that weren't that great at bottling come around after a month of conditioning, and some that were very promising at bottling being a chore to drink.
What temp did you condition at? Were the bottles properly cleaned and sanitized? You might need to let them condition longer
Yeah, I'm no expert here but I'd say that just because your basement is a consistent 73 doesn't mean your beer is going to be. Don't you at least that those stick-on thermometers on your fermentor? Check into a thermowell and a thermometer that you can use or a controller with a probe and measure those temps from in the middle of the beer.
Thank you all for your input and suggestions. I'm working toward a chest freezer and temp control, so that I can lager, but also control all of my fermentation. The next step for me is proper temperature control from start to finish. I've made considerable progress in controlling temperatures during brewing, so fermentation, and then conditioning is next. Bottles were properly cleaned and sanitized. I do have a stick-on thermometer, but I don't look at it much. I agree, the fermentation is warmer than ambient temperature. do you guys use a keeper/freezer for fermentation, even of ales?
