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I have a Thermapen meat thermometer that I use for precise temperature measurement. Although it's easy to read and fast, I'm not exactly sure how to take readings.
With a large piece of meat with consistent temperature throughout its quite easy, like a braise or meat in a stew. I am having trouble with burgers though, they are much thinner, and the temperature is very inconsistent, so it's difficult to know whether it has reached medium rare or medium or whatever.