Testing and Calibrating Thermometers

One-piece probe-type thermometers (both digital and manual), as well as glass thermometers, can be tested using the ice-point method or the boil-point method. The probe types can be calibrated, should they give an inaccurate reading. When a glass thermometer fails the test, your only choice is to compensate for the discrepancy when you use it by adding or subtracting the difference in degrees. This assumes it is off by a few degrees only; if the reading is way off, the thermometer should not be used.