Have you ever thought of taking your thermometer's temperature? The Academy of Nutrition and Dietetics and the ConAgra Foundation recommend giving your digital and non-digital food thermometer a regular check-up.
There are two simple methods to check the accuracy of a food thermometer. However, not all thermometers can be calibrated — so make sure to check the manufacturer's instructions. Thermometers that can be calibrated usually contain a nut under the dial that can be adjusted with small pliers or a wrench.
1. Ice Water Method
Materials needed: one large glass, crushed ice and clean water
After filling a large glass with finely crushed ice, pour clean tap water on top of the ice and stir well. Dip the food thermometer stem two inches into the glass of ice water without touching the bottom or the sides of the glass. Wait 30 seconds to see if the thermometer reads 32 degrees Fahrenheit.
2. Boiling Water Method
Materials needed: one deep pot and water
In a deep pot, bring water to a rolling boil. Dip the thermometer stem two inches into the boiling water without touching the bottom. Wait for 30 seconds and the thermometer should read 212°F.
For non-digital thermometers: If the temperature does not read 32°F using the ice water method and 212 °F for the boiling water method, adjust the temperature by turning the calibration nut just under the head of the thermometer until the pointer reads the correct temperature or follow the manufacturer's instructions.
For digital thermometers: Follow the instructions provided by the manufacturer. Some thermometers cannot be calibrated.
Note: In high-altitude areas, water boils at a lower temperature, so check with your local Cooperative Extension Service or Health Department for the exact temperature of boiling water in your area.