For me the biggest problem was the big drop in ambient temperature required to drop the fermentation vessel temp one degree. As you have described, the temp of the fermenting wort will continue to fall since the freezer temp has dropped so low. I dont remember it dropping more than another...
I have a single stage controller in my chest freezer and get good results with securing the probe to the outside of the carboy with a little added insulation (i.e. towels or styrofoam). The reason I dont use my thermowell is because I found that it resulted in larger "ambient" (inside the...
It's definitely not to save money -- what hobby is? For me, the principal enjoyment comes from making something delicious that I can share with friends and family and the sense of pride that comes with saying, "Yep, I made that!". But what keeps me brewing as often as I do is the craft itself...