When you are cooking you need to have tools and appliances you can trust. There is nothing worse than an oven or grill cooking hotter or colder than what the temperature gauge is displaying.
The same thing goes for meat thermometers. I’ve seen firsthand what an inaccurate thermometer can do to ruin a $100 rib roast on Christmas. Uncle Larry is still trying to live that one down.
All because of the inaccurate reading his leave-in oven thermometer was displaying. If he had only known to check his thermometer beforehand he could have saved the family from eating a dried-out piece of expensive meat.
Having an accurate thermometer is a must if you want food to be cooked properly and to a safe temperature.
In this article, I will show you how to test a meat thermometer for accuracy using a few different methods so you never have to deal with overcooked or undercooked meat again.
An Easy Way to Calibrate Your Thermometer Is to Put It in Ice Water
The easiest way to check your thermometer’s accuracy is by using a bowl or large glass filled with ice water. This will test your thermometer to see if it is reading 32 degrees Fahrenheit/ 0 degrees Celsius.
First, fill a container with ice, then with some cold water from your faucet. I like to use a large glass measuring bowl and check my thermometers all at once.
A handy tip is to grab some aluminum foil and make an impromptu cover for the ice water bowl. You can then stick your thermometers probe into the water without it falling in. You don’t want your digital meat thermometer falling in the water and ruining it if it’s not a waterproof or water-resistant thermometer like the Kizen instant-read meat thermometer.
Let the ice water sit for about five minutes and then check your thermometer. Make sure your thermometer is in the middle of the ice in the water. If you put your thermometer too deep and below the ice, you might get a reading higher than the freezing point.
Your thermometer should measure 32 degrees Fahrenheit/ 0 degrees Celsius. Now, depending on the type of thermometer you have, it may take anywhere from a few seconds to a minute (the old dial thermometers take a while to come to temperature).
If your thermometer isn’t reading 32 degrees, try moving the probe to a different area of the water. Again, make sure you have enough ice in the water if your probe isn’t reading correctly.
If your thermometer still isn’t reading 32 degrees Fahrenheit you will need to calibrate your thermometer. If you have a detached probe oven thermometer that won’t display 32 degrees Fahrenheit after the ice water and boiling water tests you might need to purchase a new probe to plug into the main thermometer display unit.
Buying Thermometers with Free Replacement Probes
I like to buy thermometers that have free lifetime replacements of their temperature probes if they stop working. The Tenergy Solis Digital Meat thermometer has free lifetime replacements of their probes. I haven’t needed to replace any of the six probes it came with and it was one of the fastest to read 32 degrees Fahrenheit in the ice water test. You can read my full review here.
How you calibrate the thermometer depends on what type of thermometer you have. In the next section, I will go over how to calibrate a basic analog meat thermometer as well as a few different types of digital meat thermometers.
How to Calibrate an Analog Thermometer
Although capable of measuring temperatures somewhat accurately, analog thermometers are quite slow and the increments on the dial can be hard to read. Take for instance the thermometer pictured above, the spacing between the 2-degree increments is incredibly tiny and hard to read.
If you are cooking something that is time and temperature sensitive like skirt steak this would not be ideal. Let’s say you wanted a steak cooked to medium-rare. Not only could your steak miss your targeted temperature while waiting for the dial to stabilize, but it would also be incredibly hard to read once it did. That’s why I don’t even use an analog thermometer anymore. Digital thermometers are fast, affordable, easy to read and make cooking easier. Here are some good digital meat thermometers that will make your life easier.
However, if you have the classic analog type meat thermometer pictured above and it’s not measuring temperature correctly, don’t fret, you can calibrate it.
You will find a hexagon shaped bolt underneath the dial display. You can adjust the needle of the thermometer by adjusting the bolt with a wrench or pliers. See picture below.
How much you need to adjust the bolt depends on how far off it is from 32 degrees Fahrenheit while submerged in the ice bath. After adjusting the hex bolt underneath, check your thermometer again in the ice bath, giving it time to reach a stable temperature.
Once your thermometer needle is pointing at 32 degrees Fahrenheit in the ice water it is calibrated and good to go.
How To Calibrate a Meat Thermometer with Boiling Water
Sometimes when you are testing your meat thermometer in ice water it won’t always read exactly 32 degrees Fahrenheit. Another way to double check the probe is to test it in a pot of boiling water (212 degrees Fahrenheit).
While testing multiple meat thermometers in ice water I noticed the SmokeBloq Wireless meat thermometer reading 33 degrees Fahrenheit. After adjusting the probe in the ice bath it still wouldn’t measure 32 degrees Fahrenheit.
Most meat thermometers are rated to be accurate within a few degrees of a target temperature. If your thermometer isn’t measuring exactly 32 degrees don’t despair. You can also check their accuracy in boiling water. Some thermometers will measure higher temperatures better than lower ones so it’s always a good idea to double-check a thermometer using both the ice water and boiling tests.
The test is pretty straight forward. Bring a pot of water to boiling and stick your thermometer in to test it. A handy tip is to create an aluminum foil cover to insert your probe as we did for the ice water test, except only cover a portion of the pot like the picture above. You want to make sure that you keep the area where your probe connects with the cord out of the water because that will allow water to get into the probe and ruin it.
If after the ice water and boiling water tests your thermometer isn’t reading correctly you will have to calibrate it if you can. If you can’t you will likely need a new thermometer or replacement probe.
That leads us to the topic of calibrating a digital meat thermometer.
Calibrating a Digital Meat Thermometer
It really helps if you have the instruction manual if you ever need to calibrate your digital meat thermometer. Some thermometers can be calibrated, some can’t. If your thermometer isn’t measuring accurately after testing it with the techniques above you need to figure out if the thermometer can even be calibrated.
For example, the Lavatools Javelin PRO Duo thermometer that is pictured is capable of being calibrated. To reset or calibrate this particular thermometer you just need to open the battery compartment and move all the tabs down, which will reset the thermometer to factory settings.
Some thermometers can be calibrated by simply holding down a button for a certain amount of time. If you are unsure if you can calibrate your thermometer you might need to research the make and model of it online.
Having an accurate meat thermometer is an essential tool if you want to cook foods to their best serving temperatures. If you aren’t sure if your thermometer is measuring temperatures accurately you will need to calibrate it if it’s possible. As you can see, some thermometers can be calibrated and some can’t. If you have a thermometer that isn’t accurate and you’re not sure if it can be calibrated, your best bet is to find one that is capable of calibration.
A dependable accurate thermometer is a wise investment if you think of all the future cooking you will encounter. Knowing the proper serving and cooking temperatures of food is just part of good cooking. Check out our other articles on the best cooking and serving temperatures of all types of food here.