The bimetallic coil thermometer is not a satisfactory device for measuring food temperatures for the following reasons as shown in the photographs.
3. For many mechanical reasons, the stem can get filled with liquid from food or wash water that seeps in around the gasket at the nut. This device is not designed to be immersed. The Oregon Department of Agriculture has reported that when inspectors check thermometers in operation, they are often off by more than 10F.