I wasn’t planning on having to ferment in my fridge, let alone battle mosquitoes during mid-march, but evidently high 70’s and low 80’s are here to stay for a while in Michigan.
I have a ranco 2 stage and a ferm wrap, and my 80/- is getting warmer than I wanted, although it is conveniently at day 5 and while i was planning on a diacetly rest I don’t want it going above 69 or 70 (65 is the desired ferm temp for this recipe, i was going to bump it to 68 for the d-rest) So…I need to chuck the whole works in the fridge and I’m unsure what I need to set my heat, cool and buffer numbers at to hold at 68. Thanks in advance
If you have the temp sensor taped to the side of your fermentation vessel (or are using a thermowell), and are therefore measuring the actual beer temperature, you should be fine just using 68 degrees as your set point for both heating and cooling with the minimum 1 degree differential.
If you are forced for some reason to let the temp probe hang in space (and are therefore measuring the ambient temp in the fridge), I would still use 68 as your set point. But you’ll want to set your cooling differential to 3 or 4 degrees. Keep the heat at 1 degree.
The only reason for the 3-4 degree differential when cooling is to avoid short-cycling your compressor. If you are measuring the beer temp, this is really not an issue - Beer is still mostly water, and takes a long time to change temperature, so you don’t have to worry about this short cycle issue.
EDIT: I just realized you were talking 1 degree on the heat side, just ignore this post. :-[
I don’t have a Ranco so this advice might not be worth a crap, but when I set mine to 1 degree it would occasionally cycle the freezer for about a second then shut it off. The temp reading would sometimes flip back and forth from, say, 67 to 68 then back to 67 as it was warming up. I switched to a 2 degree swing and it solved than problem. When I set to 67 it will go down to 67.9 then up to 69.0 then back down, effectively 68. Stupid but it works.
I have a Ranco dual stage with the probe under some insulation on the side of a stainless 15 gallon corny keg. I set my cooling temp to whatever my desired fermentation temp is and the heating temp at one degree below that. I have a 1 degree variable on both temps. There is very little swing and no cycling of the chest freezer. I use a heating pad in the freezer as my heat source.