I have a question for you all. Here it is, in context:
I brew a batch of Hefeweizen with extract and a 3 gallon boil. I then add some cool water, to get to 5 gallons, and dump it all into the carboy. I shake it like a girl in a rap video (for proper aeration, of course) and take the temp = 76 degrees. This seems grand, so I add the yeast cake from the previous batch of Hef, which was just racked to secondary. All seems swell, no? I come back about 6 hours later and the wort is fermenting "like crazy". Unfortunately, it's worked itself up to ~88 degrees and I start getting p-noid about fusels and whatnot. So I wrap it in a wet towel, and in the next 12 hours or so, it drops down to 68 degrees. Then the ferment slows down and it stops (total of less than a day of action). Hydrometer says 1.023. Joy has ceased. I turn up the temp in the house and get the beer up to 72 degrees, but no return of the bubbles.
So, three questions. One, did I scare the yeast off by the sudden drop in temp? Two, how slowly should one drop the temp in a situation like that? Three, in general, how do you all approach the task of bringing your new wort from the 70-76* range that is suggested for the yeast to begin, to the lower temp at which fermentation should be sustained?