I have to do my fermentation in my basement, which at this time of year gets no warmer than about 58 degrees. On Monday I started a new batch (my second) and by Tuesday it was bubbling away happily. The temperature of the brew, according to the stick on thermometer, was 64 degrees and it stayed there for a couple of days. I have wrapped an old sleeping bag around the fermenter. This morning (Friday) there was still some bubbling, but the temperature had dropped to 61 degrees. I have a brew belt heater that I could put on that would probably raise the temperature up to the high sixties. Should I do that or just see how it all plays out at the lower temps?