One method uses ice water, the other uses boiling water. Many thermometers have a calibration nut under the dial that can be adjusted. Check the package for instructions. Calibrating a Thermometer There are two ways to check the accuracy of a food thermometer. One method uses ice water, the other uses boiling water.
Many thermometers have a calibration nut under the dial that can be adjusted.
Check the package for instructions. To use the ice water method, fill a large glass with finely crushed ice, add clean tap water to the top of the ice, and stir well. Immerse the thermometer stem a minimum of 2 inches into the mixture, touching neither the sides nor the bottom of the glass. To use the boiling water method, bring a deep pan of clean tap water to a full rolling boil. Immerse the stem of a thermometer in boiling water a minimum of 2 inches and wait at least 30 seconds.