I recently brewed up a batch of Golden Strong - Much more yeast (and sugars) than I have done in the past. While I don’t yet have a good process for temperature and control, this batch (5.5 gal) fermented in glass at around 62-66 degrees for a week. Strong fermentation for about half of that and then very quiet by the end of that week. Knowing that it needed to get hotter, I added heating for a handful of days and brought the batch slowly to about 76-78. Strong fermentation began again and continued for a couple of days. But, I don’t have a way to really get this to 80 degrees and hold it; one day I was away and no heat was applied and the temp dropped – It has been sitting at around 64 for the past week. (My heating pad set-up shuts off automatically). I have not yet tested gravity - but assuming that it is still higher than expected FG, any harm in working hard to bring the temp back up for another round??
Take a gravity reading and see if you have a problem before trying to fix it. If it was high 70’s for a few days, might be done.
What he said. It isn’t necessary for big Belgians to hit 80F.
+2 - I’ve fermented quads in the low 60s without touching the temp and they’ve turned out great. With a big healthy pitch of yeast most Belgian strains will gobble up everything you feed them without needing much help.