Kombucha or sprout heater from a potpourri pot or other appliance?
I need something to heat a bucket of kombucha tea to 70 degrees Fahrenheit when the heat is off in the kitchen where I will be keeping it. The temperature dips below 50 degrees Fahrenheit in there. I also need something to warm sprouting jars, which I'll be keeping on a shelf that I plan to enclose with a window blind or something else to keep the heat in, but allow ventilation. I don't think I need a thermostat for either of these. The temperature doesn't have to be exact.
For the kombucha, I could buy a heating pad for $60 or a heat belt for $20 and pay to have them shipped or I could go to the local aquarium store and buy some fish tank heaters, but I'd prefer to spend less, make something myself out of something old and not support an aquarium store. I'm not a big fan of fish prisons.
The thrift stores around here have lots of old appliances for $2-$5 each. I thought I could make heaters using the heating element of one of the small potpourri pots I've seen at Goodwill. I saw online that these pots are heated with a wire wrapped around the (irremovable) pot. Any thoughts on how I could make heaters with this heating element that are safe and not too hot? Any ideas using other appliances?
Another option would be to find a cheap heating pad (for heating people) without auto shutoff and use that on the Kombucha at least. I'm not sure that that would be warm enough though, but maybe it's a more worthwhile option that trying to make a heater. What do you think? Should I forget making something for the Kombucha and look for a heating pad instead?
Thanks for your help.