Originally Posted by BiologistBrewer
I am much more concerned about it going through really dramatic changes in temperature quickly than I am about the actual temperature.
At 80 degree room temperature and with 10 gallons of fermenting beer and >5 gallons of water in the bath, my fermentation temperature doesn't change dramatically when I add a half gallon of ice. Empirically, I observe fluctuation from 66-70 throughout the day, but that is a pretty smooth curve.
Experts, am I doing bad things for my beer by allowing fluctuations in that range over the course of a several hours (four peaks/valleys per day)? Thanks for the discussion!