I don't know, but just another thought here, two small (18 gauge) solid (not stranded) wires with only the insulation stripped off the first 1/4" of each end can be pushed through the sight glass to your heating element cut off level (stagger the wires so that one is lower than the other so the stripped ends can't touch) and these wires can be hooked up in series on the control wire that activates the relay that turns on your heating element. The wort acts like a conductor. Just a thought.
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