So, last night I brewed up a stout and as I was chilling the wort I noticed the electric thermometer that I was using seemed off. I tested it out in some cold water and sure enough, it wasn't reading accurately. It was late and I don't have another thermometer, so had to go by feel. I pitched the yeast (Nottingham Dry) when the wort felt cool enough and promptly remember I had one of those little fermometer strips on the carboy. I checked the temp and was a little worried as it was over the 78 degrees that the fermometer tops out at.
I went to bed worried that I had killed off my yeast. I checked the temp in the morning (about 7 hours later) and it was at 77 degrees and looked like fermentation was starting. It is now 9 hours later (16 from the time I pitched the yeast) and the temp is 68 degrees and actively fermenting.
The good news is that I can be pretty sure that I didn't kill the yeast. The concern I have is that I know fermentation at higher temperatures can produce Esters and Fusel Oils and off-flavors. Could the high temps for 13-14 hours be enough to cause off-flavors?