You Need a Calibrated Thermometer for Food Safety

Hey, folks! We got a great question about thermometers. Food vendors are often required to use a “calibrated” thermometer to make sure foods are prepared, stored, and served at safe temperatures. Nobody wants to cause food poisoning, and that's a surefire way to lose customers.

What Does Calibration Mean?

Calibration is just another way of saying you've tested and adjusted your thermometer to make sure it's reading temperatures properly. If your thermometer says 150 degrees, you want to know that the food is actually 150 degrees — not 140 degrees, and not 160 degrees.

How to Calibrate a Food Thermometer

Calibrating a thermometer is easy to do, but most people have never had to do it, so they assume it's complicated. Here are some simple instructions so you can do it yourself!

Ice Water Calibration Method

1. Fill a 2-quart measure with ice. Add water to fill in spaces around ice cubes.
2. Let sit for one minute.
3. Place thermometer in ice water so that the sensing area of stem or probe is completely submerged over the dimple.
4. Keep the thermometer from touching sides or bottom of container.
5. Let thermometer stay in ice water for at least 30 seconds or until the dial stops moving.
6. Use a wrench or other tool to turn the hex adjusting nut. Rotate the nut until the dial reads 32°F, while in ice water.
7. Some digital stemmed thermometers and thermocouples have a reset button that you need to push.

Boiling Water Calibration Method

1. Fill a sauce pan with water and bring water to rolling boil.
2. Place thermometer in the pan so the sensing area of the stem or probe is completely submerged over the dimple.
3. Do not let the thermometer stem/probe touch sides or bottom of container. It should only be touching water.
4. Keep thermometer in the boiling water for at least 30 seconds, or until the dial stops moving.
5. Use a wrench or other tool to turn the hex adjusting nut. Rotate nut until the thermometer dial reads 212°F, while in the boiling water.
6. Some digital thermometers have a reset button that you push to set the calibration.

Note: The boiling point of water is about 1 °F lower for every 550 feet above sea level. If you are in high
altitude areas, the temperature for calibration should be adjusted. For example, if you were at 1100 feet
above sea level, the boiling point of water would be 210°F instead of 212°F.

Keep a record of the date and method of each calibration, and remember to recalibrate your thermometers if they are dropped, or as frequently as required by your local health department.

Additional information.