There is obvious appeal to buying an infrared thermometer for cooking – it can measure food temperature without touching it. However, the same things that make it a great thermometer are also its downsides. There are limitations to using an infrared thermometer in water, or its inability to be used in other situations. 

Part 1. Can You Use an Infrared Thermometer in Water?

The short answer is no. But the long answer is that there is a specific technique to use when measuring water temperature with an infrared thermometer. If you want to use an infrared thermometer to measure the temperature of water or another liquid, you have to stir the liquid vigorously before measuring it. The stirring action will ensure that the liquid on the surface is at the same temperature as the liquid below. 

However, you cannot use an infrared thermometer to measure the temperature of boiling water. The boiling action releases steam, which can result in inaccurate temperature readings. 

Part 2. What Type of Thermometer is Best for Water?

There are specific types of thermometers designed to measure water temperature. One example is a floating thermometer. It is an excellent tool for measuring water temperature, especially when you need to achieve a precise temperature level for a specific purpose. 

The floating thermometer has a dial that will stay on the water’s surface. It displays the water temperature while the probe is submerged. The probe will sense temperature changes and display them on the dial. 

Part 3. Is an Infrared Thermometer Accurate on Liquid?

No. As mentioned above, an infrared thermometer cannot come into contact with water. It only measures the surface temperature using the stirring technique to ensure an even reading below the surface of the water. 

As with measuring food temperature, the reading of water temperature is affected by many external variables. Hence, it is vital to check the accuracy rating for the specific model of infrared thermometer you are using. In addition, you must regularly calibrate your thermometer to ensure accurate readings. 

Can Infrared Thermometers Work Through Glass or Clear Plastic?

No, you cannot use an infrared thermometer to measure the temperature of any object through glass, clear plastic, or any other transparent surfaces.

The temperature reading from the infrared thermometer will be that of the transparent surface, not the object behind it (or contained within it). 

Nothing must stand between the object and the infrared thermometer to get the most accurate reading. 

What Temperatures Do Infrared Thermometers Measure?

There are various types of infrared thermometers, and their temperature measurement ranges vary accordingly. A clinical infrared thermometer offers higher accuracy in measuring body temperature. The temperature range for clinical purposes is from 32 to 42 degrees C. 

On the other hand, industrial infrared thermometers offer a wide temperature range because they operate at extreme temperatures. The typical range is from -50 to 100 degrees C. 

Part 4. Best Practices for Using an Infrared Thermometer

Infrared thermometers are great for cooking and many other applications. However, there are certain limitations to their use and application that you should be aware of. It also pays to know the best practices when using an infrared thermometer to ensure you get the most accurate readings.

1. Always measure temperature from a distance.

Infrared thermometers are great for measuring the temperature of food or other objects from a distance. No contact is required between the infrared thermometer and the object to ensure accurate readings. Therefore, an infrared thermometer is your best option if using a probe isn’t possible (such as with impenetrable frozen food) or when dealing with extremely high heat. 

2. Field of view matters in using an infrared thermometer.

Consider the target size, distance, and angle when measuring an object or food with an infrared thermometer. These factors determine the surface temperature. Therefore, you must get the right angle and distance to get the closest possible reading, even when you cannot touch the object or food.

The best angle to measure water or any surface with an infrared thermometer is to hold the device at a right angle. This angle will create a tight circle around the object’s perimeter. 

The Bottom Line

There are several practical uses and applications for an infrared thermometer, whether in or out of the kitchen. If you use it for measuring liquids in cooking, it’s essential to know the device’s limitations and follow the best practices recommended above. 

If you need a precise temperature reading for water or any liquid during your cooking process, turn to other thermometers instead. They will help you produce a more accurate reading when you submerge the probe sensors in the liquid rather than taking the surface temperature, as with an infrared thermometer.