My batch yesterday may have been a total disaster, though I won’t really know until I taste the beer. I did a partial mash and damn it, my thermometer didn’t seem right so i decided to use another one. I through that one in and yup a totally different reading. I couldn’t help myself but be nervous about which one to trust, so i added a third therm to the equation, and guess what, a third totally different reading. Sadly i eventually found a fourth therm and guess what, that one was another reading all together. WTF!! I had been reading a lot about the thermapen and although it is expensive, i decided to pull the trigger. Is my story unique or has any one else had a similar experience?
What thermometers are we talking about? All bimetal?
In your case, if you have any doubts, I’d pull out your laboratory-grade thermometer (the glass one that most of us got when we purchased homebrew starter kits ages and ages ago). It should be 100% accurate, and the fall-back thermometer in case things go wrong.
I had a cooking digital thermometer, two bimetal thermometers, and the one glass thermometer that came with my kit. I defaulted to the glass thermometer for the most part but it is hard to trust anything when you have four different readings.