My Johnson A419 digital controller will be arriving in a couple of days. I have my freezer ready and will use the controller to keep my kegs at around 54F.
So what are the best settings on the controller:
obviously 54F will be one of them, but set to shut-off?
What about the differential?
It also seems that opinions differ with regard to how to place the probe. Given the buffering of a large thermal mass (5 gallons of beer in a keg), I'd initially have gone with trying to keep air-temp at an average of 54F, but with a large differential (due to the slow changes in temp of the kegs).
However, many forum users report that attaching the probe to the side of the keg, covering it with a little insulation and tape (or even plumber's putty) works very well. I would expect the differential to be set to a much lower tolerance using this method.
Thirdly, using a thermo-well.
So, my options would be:
A. 54F set-point, 4F differential either side of the set-point, probe in the air.
B. 54F set-point, 1F differential either side of the set-point, probe taped and insulated to the keg.
C. 54F set-point, ? differential, probe in thermo-well (1 g water)? But are the Johnson probes really waterproof?
I know this may open a can-of-worms, but I'd appreciate any comments, from folk of have experienced these different methods.