So, I am trying to convince my wife that a yogurt maker is the most useless piece of hardware for any kitchen. I want to prove to her that I can make good yogurt without it. Unfortunately, I am having trouble controlling the temp. at about 100 degrees for 8 hrs. Then, I thought of this....am I nuts? What if I put the milk and starter into a mason jar and tossed (ok, placed it gently) in the spa? Our hot tub is set at 103 right now. Stays pretty constant...aside from possible breakage/spillage...any downside?