I chased down the curve of a microwave cooking probe. The way I did it depended on the temperatures of interest.

most temps
Stuck good and bad probes in a potatoe
Used peanut oil and the stove

Low temps
Stuck good and bad probes in a potatoe
Water and added ice cubes

I got an excellent curve match. It also turned out, that a random probe I purchased had the same curve.

The bad probe actually had an intermittent contact. The actual readout was broken at the time.