50-60 F OK for Ale Post-Fermentation?

Hi all,

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?

I guess my answer is "it depends". I use a cooler, and it's filled with water, so that the water temperature is approximately the same temperature as the beer inside the fermenter.

If you're using just a little bit of water, the temperature inside your fermenter might be quite a bit different. Can you check the temperature of the beer and see where you're at? If you have a stick-on LCD thermometer strip, that would be fine. The important time is during fermentation, and if it's fermenting, it's probably not under 59 degrees. It takes a long time for 5 gallons of beer to change temperature, so even if your water bath is fluctuating, I would guess that the beer inside isn't.

I've read that fermentation in the carboy can be around ten degrees hotter than the ambient temp, but don't have the personal knowledge to back that up

The water comes to about the midway point of the carboy.

During the first few days of fermentation, the LCD stick on thermometer usually said ~68 degrees, but it was a cheap fishtank one I got at Walmart right before brewing (since the LHBS was closed) It got wet from the t-shirt covering the carboy, and fell off about a week ago. I have a real one now... I'll try to clean/dry part of the carboy above the water and hopefully get it to stick, though the t-shirt makes it hard to keep it from getting soaked.

I'm not at home, but I'll update once I figure out the temp on the carboy.

Couldn't find the thermometer, but I took the temp of the sample I used for gravity readings. Looks like it's ~68 degrees, so I guess I'm in the clear.