I broke in my newly completed HERMS this Sunday by brewing Jamil's Koelsch. My OG was a little off (low) due to poor fly-sparging technique but otherwise all was well.
I whirl-pooled and cooled to ~58 deg F w/ my immersion chiller before oxegenating and pitching 2 tubes (no time for a starter) of White Labs German Ale / Koelsch Yeast purchased from a local shop w/ an expiration date of Feb 2010. The yeast was in a fridge at the local shop and in my fridge until about an hour or two before pitching.
I tossed the 6.5 gal carboy in a too-cold fermentation chamber (wasn't paying attention when I put it in there) where it sat a bit cold (~55ish deg F). I didn't check on it for 12 hours and when I did there wasn't really any sign of fermentation. It was at this point that I first noticed the temp was so low. Hoping to kick start the ferment I filled a couple gallon jugs with hot water, put them in the ferm chamber, and hit the beer with another blast of O2. Another 12 hours later the chamber was up to 61 deg C (my set-point) and there still wasn't much of anything going on, so I hit it with another shot of O2. About 36 hours from the pitch fermentation is finally going, albeit slowly.
I've never had a ferment crawl like this before but I've also never pitched an ale yeast this cold (as suggested by Jamil). I suspect it was just the low temps that got me off to a slow start. Thoughts?
My real questions are: Were my repeated blasts of O2 a good or bad idea? I know O2 late in ferment is bad but I figured these were OK because not much activity was happening. Besides a higher risk of contamination, what kind of faults in my beer can I expect from the slow start? Anything I could/should do at this give my beer the best shot of tasting it's best?