I have been using an open swamp cooler (large bucket w/o top, water, T-shirted carboys, box fan on nearby chair) for a few weeks, and have been changing out frozen water bottles a couple times a day. What I'd like to know is if my beer ferments fine (bubbles, churns around, etc) for the first few days, does that mean the temperature of my water is ok for the remaining 2-3 weeks it's in the primary?
The reason I ask is because I checked the water temp in the cooler today about an hour after changing out the water bottles, and the temp read ~50 degrees. My guess is the water temp has been between 50 and 60 degrees on a consistent basis, depending on whether the bottles are newly swapped out or not.
Is this temp low enough to harm my ale (like put my yeast to sleep after initial fermentation), or require added time at a slightly higher temp?
Should I stop changing out frozen water bottles (or use fewer) for a couple more weeks, to get the water closer to 60-65 degrees?