Fermentation Issue

I have had a batch in the primary for 1 week as of today. It is set in a large styrofoam cooler with extra insulation I had from insulating our crawl space placed in the void in the cooler, then wrapped with a few towels where the fermenter comes out. I cut a hole the diameter of the fermenter in the lid, so it sticks out a bit. Anyway, it started out around 68 and held there for a few days, between 66 and 70. Since the beginning of the week, it’s been in the 30’s at night and this room gets kind of chilly. I’d guess in the 50’s perhaps. I’ve been checking it daily to make sure it didnt get too low or too high and the beer has been around 60-62 judging by the LCD strip thermometer thing. However today, a heater was accidentally turned on in the room, and when I got home, I checked the temp as it seemed warm in the room and it was at 77. Quite a change. I’m thinking it will be okay given that its been a week already, and I plan to leave it alone but just let it slowly get back down to the mid 60’s. I am planning on leave it in primary for a week, then in a secondary for two weeks for a dry hop, then bottle.

Any input? At what point is it okay to let the beer go below the optimal range for fermentation for the yeast?

In my experience most beers flavor profiles are set in the first 72 hours. It was probably a good thing that you increased the temp to help the yeast clean up after themselves. Assuming it is not a lager at 60 degrees, it will be just fine, no worries.

Even though this was an accident, would it be prudent to do this in the future, but to a lesser degree?

Yes,
You should verify with past brewing network podcasts, but Jamil is big on raising the temp of the yeast before the main fermentation is complete in order to achieve a complete fermentation. I have followed and like the results, my beers finish at a much lower gravity and have much less fermentation character flaws.

Like was said above, I’ve read many times that fermentation temps (for ales) are critical during the first 48-96hrs of active fermentation. Outside of that it’s not a big issue. I routinely start my fermentations in a mini-fridge at around 60-65F. As I notice the bubbling slow down I slowly raise the temp a degree or 2 every day for a few days. Then let it sit at 68-70 for another week or two.

Lagers are kinda the same deal. I start at 45-55 depending on the yeast. After about 5-7 days I slowly raise the temps a few degrees a day until it’s into the mid sixties and let it rest for 2-3days for a D-rest. Then if fermentation is complete (usually about 2-3weeks in at this point) drop it down to lagering temps.