I had my fermenter in the closet where I had been checking it daily to make sure it was the right temp and it was for the first 3 days. Then my finance left the door open and the temp dived. Should I bring the temp back up or just leave it alone?
64F is still within the lower limit of most ale yeasts' temp range. That should still work. But you may have to swirl the yeast back up. The sudden drop in temp can cause them to settle,even though it's still within temp range.