Infrared Thermometers

Q: Can I check grilling temperatures with an infrared thermometer?

A: When measuring the temperature of a grill or grate, the temperature of the surfaces visible through the holes are also factored into the final reading. To accurately measure the temperature of a grate or grill, place a solid surface like an iron plate or skillet on the grill, let it come to temperature then measure the plate or skillet. Spraying a little cooking oil on the plate or skillet will ensure proper emissivity.

Q: What is emissivity?

A: “Emissivity” is a measure of a material’s relative ability to emit radiated energy. For more information, please see Emissivity and Infrared.

Q: Can I check if food is properly cooked with an infrared thermometer?

A: Infrared thermometers only measure surface temperatures and therefore not very effective at testing if food is properly cooked. We recommend you use a traditional probe thermometer for this.

When measuring liquids such as soups and sauces, ensure you stir vigorously before taking a measurement to balance out the overall internal temperature. Bear in mind steam (even when a liquid is not boiling) can condense on your thermometer and affect the accuracy of your reading.

Q: Can infrared thermometers work through glass or clear plastic?

A: No, an infrared thermometer will not measure temperature through glass, liquids or other transparent surfaces. Although visible light can pass through it, the infrared thermometer will measure the surface temperature of the window itself, not the object beyond it.

Q: Can an infrared thermometer measure temperature through water?

A: No, an infrared thermometer will not measure temperature through water, it will only measure its surface temperature.

Q: What is spot size, spot ratio and distance to target (DTR)?

A: Two variables control the “spot size” of any given measurement:

  1. The distance to target ratio (DTR) of your particular infrared thermometer
  2. The distance between your infrared thermometer and the target

For more information, please see spot size.

Q: Do I need to clean my infrared thermometer?

A: Yes, an infrared thermometer should be kept free of dirt, dust, moisture, fog, smoke and debris. Particular care should be taken to keep the infrared lens or opening clean and free of debris. For more information, please see Cleaning and Caring for Your Thermometer.

Q: How do I turn the laser on?

A: It depends on the type and model of your infrared thermometer. Please refer to your user manual for the full range of features and how to use them.

Q: Why am I getting strange readings on shiny metals?

A: Highly polished/shiny metals tend to be very reflective and subsequently provide a low emissivity value. With low emissivity materials, energy is reflected not absorbed. For example, a reading from a stainless steel pot filled with boiling water will more likely be closer to 38°C than 100°C because the pot is reflecting the room’s radiation more effectively than emitting its own energy.

Q: Can I calibrate my infrared thermometer myself?

A: Infrared Thermometers can be calibrated for accuracy just like any other thermometer. In Ross Brown Sales’ Laboratory, using industrial black bodies, our technicians calibrate infrared thermometers within Australian Standards and include a 12 month traceable certificate.

If neither an industrial black body nor a comparator cup are available, you can do a quick calibration using a properly made ice bath