My basement has been about 60, and on Saturday I started a stout using Belgian yeast (wlp500). I don't have warmers or anything like that, so I just set it touching the hot water heater. It got a good start and is at 68-about what I want. The ambient temp in that spot is closer to 63. I really didn't want the yeast to crap out, and it looks like it's in the range...my only concern is that sometimes the HWH is warmer than it is at other times, and I don't want the fluctuation to mess anything up. I'm not overly concerned, given that it is not an official style (Belgian Imperial Stout)-but I was wondering if anyone had any thoughts.