My 2 cents: You don't need a thermometer for peanut brittle. You can go by sight and smell. I look for the boiling bubbles to be straw colored. If I used a thermometer, it would be the thermapen. You simply wipe the probe with a cloth towel between tests, if you are worried about it. My recipe is similar, but calls for butter, vanilla and salt. Once temp is reached, I remove from heat and stir in butter. vanilla and salt. This causes it to steam briefly. Then I add soda. It foams up almost to the top of the pot. Pour out and after a minute, I stretch to make it thin.
