Accurate temperature measurements are crucial for ensuring optimal performance, reliable data, and, most importantly, the well-being and safety of individuals. However, over time, thermometers can experience deviations in accuracy due to various factors, including regular usage, environmental conditions, or even mechanical wear. Step 1: Fill an Ice Bath Mug to the very top with ice (crushed ice is preferred as our test below indicates this achieves the best results). If you do not have an Ice Bath Mug then any large glass or container would suffice.

Using the reference readings from the Fluke 566 IR, we subtracted the average reading achieved from the instruments to show the “actual” result. The frequency of calibrating food temperature probes depends on several factors, including industry standards, regulatory requirements, and frequency of use. Step 7: Taking extra care to ensure that the “field of view” (the size and shape of surface area being measured) is well inside the sides of the ice bath mug, press the button on your infrared thermometer to take a measurement. The only limitation of these, however is that they only confirm the accuracy of your thermometer, not your probes. Your probes will have to be calibrated separately using one of the other methods described in this blog. In conclusion, if you perform the test correctly, and your infrared thermometer is properly calibrated with an emissivity setting of 0.97, it should read within your unit’s stated accuracy specification at 0.0°C.

When carrying out a calibration process, it’s often useful to have a highly accurate reference or calibration thermometer to compare the thermometer under test with. It enables you to be confident in measuring your stable temperature source, particularly if using a less reliable method such as an ice bath. If you haven’t already, we would suggest reading the other blog posts in the infrared series before attempting this method as they explore emissivity, thermal stability and other factors that affect the accuracy of your readings. The calibration method you choose depends on how many thermometers you need to calibrate, how often you need to calibrate them, and the time and budget you have allocated to this process. Whichever one you go for, the most important thing to remember is to carry out each test with care and precision so that results are accurate and you can continue using your instruments with confidence.

All of the instruments on test have an accuracy of ±1°C at 0.0°C, so as you can see from the results they were all within their stated accuracy specification when calculated from the average reference temperatures of the calibrated Fluke 566 IR. The comparator cup is a budget option, ideal for calibrating smaller numbers of infrared devices on a less frequent basis. You simply insert a high-accuracy probe into the base of the cup to use as your reference point whilst taking a reading inside the cup using your infrared device. Then compare the two readings. The limitation of this is that it is difficult to use the cup to calibrate your IR thermometer at various temperatures, particularly high and low ones. Factors such as steam and condensation need to be taken into consideration when using infrared thermometers. However, with care, it is possible to use the comparator cup at low temperatures by storing it in a fridge or freezer so it can acclimatise. Step 4: Create a well of open water where no ice is floating or push the ice down so there is a layer of open water at the top of the ice bath mug. In the last blog post within our infrared thermometer series, we looked at how to correctly validate the accuracy of your instrument using a Thermometer Comparator. The comparator method allows devices to be validated at ambient room temperature, however we would not recommend conducting it at hot or cold temperatures as this lowers the accuracy of the readings. If you need to validate your thermometer at a cold temperature, you can use the ice bath method to achieve a fairly accurate result by following the guidelines below.Using our UKAS calibrated Fluke 566 infrared thermometer we took reference readings from each ice bath three times and determined an average temperature. Noting this temperature down, we then used the same method for our Thermapen IR, RayTemp Blue and RayTemp 3.

The emissivities of all the infrared instruments were set to 0.97, apart from the RayTemp 3 which is fixed to 0.97 as default. Note: If the ice floats up off the very bottom of the container then the ice bath is likely warmer than 0.0°C. Pour off any excess water.

If you have verified the accuracy of your thermometer and found it to be out of range, you’ll need to send it to a laboratory to be recalibrated. At ETI, we have eight in-house calibration laboratories, including three UKAS laboratories and one specifically designed for infrared calibration. It’s essential to keep a record of calibration dates and results to demonstrate compliance with regulatory requirements and to ensure proper monitoring of your thermometer’s accuracy. Regular calibration not only promotes food safety but also supports quality control and helps prevent potential issues that may arise from inaccurate temperature measurements. In many industries, including food service, the general recommendation is to calibrate food temperature probes at least once a month. This frequency helps to ensure that the thermometer remains accurate and reliable for temperature measurements. However, certain situations may require more frequent calibration, such as HACCP plans, high-volume usage and regulatory requirements.

This guide will explore various calibration equipment options available in the market today. We will cover a range of tools, from simple and cost-effective solutions suitable for home use to more advanced and specialised equipment utilised in professional settings. Each type of equipment serves a unique purpose, catering to different calibration needs and budgets.

Note: All of our ETI manufactured infrared products allow you to change the emissivity. Please refer to the instrument’s operating manual for instructions on how to change this setting. Step 6: Hold your infrared thermometer about 5cm above the top of the cup or 8cm from the surface of the water and make sure that the lens or opening is directly above and perpendicular to the surface of the ice bath. Following the steps above, we created an ice bath using one of our Ice Bath Mugs. To ensure that the bath had been made correctly, we used a Thermapen Professional to test the temperature of the water. As you can see from the image below our Thermapen was showing a temperature of 0.0°C. Note: If you hold your infrared thermometer too far from the surface of the ice bath or hold it at an angle, your measurement will include the sides of the ice bath mug or even the table it is resting on and give you an inaccurate reading.