Thermometer Calibration
Food Foundations Sub Food Foundations News
Both probe and infrared laser thermometers must be calibrated to ensure they are giving a correct reading.
Calibration is a comparison between a known measurement (the standard) and the measurement using your instrument (in this case a probe thermometer).
There are 2 ways to calibrate your thermometers:
- Ice Point Method
- Boiling Point Method
Ice Point Method
- Fill a large cup or small container with crushed ice, then add clean fresh water to a depth of at least 10 cm – make a slurry of half ice, half water.
- Stir ice and water, wait 2 minutes – allowing water and ice to cool and mix.
- Suspend the stem of the probe thermometer into the ice slurry or shoot infrared thermometer into the ice slurry. Note: Avoid probe touching sides of bottom of cup or container.
- Wait 2 minutes until the indicator stops changing.
- The temperature reading must be 0°C +/-1 (so anything between -1°C and +1°C is fine).
- If your thermometer is not in this range then your thermometer is not accurately reading the temperatures on the cold end of the scale and will need to be replaced or re-calibrated (if your thermometer is adjustable).
Boiling Point Method
- Bring a medium saucepan of fresh water to a rolling boil on the stove.
- Immerse the stem of the probe thermometer into the boiling water or shoot infrared thermometer into the boiling water.
- Wait 1 minute, read temperature on thermometer while still immersed in boiling water.
- The temperature reading must be 100°C +/-1 (so anything between 99°C and 101°C is fine).
- If your thermometer is not in this range then your thermometer is not accurately reading the temperatures on the hot end of the scale and will need to be replaced or re-calibrated (if your thermometer is adjustable).