How to Check if your Thermometer is Accurate

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Let’s face it: barbecue thermometers have a hard life.

They are often dropped, splashed, rained on, and subjected to harsh environments.

It’s simple to see how even a high-quality thermometer may lose accuracy with time.

If you use an incorrect thermometer to keep track of your pit temperature or to determine when the meat is done, you will serve subpar barbecue.

Fortunately, there are several basic tests you may do at home to determine the accuracy of your thermometer. Most thermometers may then be calibrated at home, saving you money on new probes.

Why you should test your thermometers regularly

How to Check if your Thermometer is Accurate

At least once a year, you should verify the accuracy of your thermometers.

If you recently dropped or mishandled your thermometer in any other manner, a rapid test may be in order right now.

If you do not do so, you risk relying on erroneous temperature data. This might lead to you:

  1. removing meat off the grill before it is cooked (or keeping it on for too long)
  2. And maybe endangering your friends and family with raw meat.

You don’t want to be held accountable for any of them!

The good news is that if your thermometer is out of whack, a simple calibration can often have it running like new again.

You need to check your thermometer specs

How to Check if your Thermometer is Accurate

We’ll teach you the best technique to test your thermometers in a second, but first you should acquaint yourself with the manufacturer’s specifications for your thermometer.

My Thermapen arrived with this calibration certificate, which I thought was a lovely touch.

Thermoworks, a well-known maker of high-quality thermometers, describes the information that a manufacturer should provide:

Reputable thermometer manufacturers provide the specifications of their devices on the box.

With thermometers, this should contain the temperature range the thermometer is meant to measure, the accuracy it should demonstrate throughout that range, the speed at which that accuracy should be displayed, and the resolution it will display (usually whole degrees, tenths, or hundredths of a degree).

Reproducibility (the instrument’s capacity to repeat its performance without hysteresis effects) is also an essential aspect.

There is no need to calibrate as long as the reading is within the range of accuracy.

This range may contain more wiggle area than you imagined, depending on the quality of your thermometer.

It’s possible that your thermometer is still accurate, but your needs have changed. If your thermometer does not claim to produce reliable readings, you may want to consider updating it.

How to Test Your Thermometers Accuracy

An ice bath test or a boiling water test is the best approach to assess speed and accuracy.

The tests, as the names imply, require comparing the accuracy of your thermometer to a known temperaturefreezing point or boiling point.

In certain circumstances, conducting only one of these tests can suffice, and since the ice bath test is simpler, many people choose to use it. Some manufacturers suggest doing both tests to confirm that your thermometer is accurate across many temperatures.

1. The Boiling Water Test

Water boils at 212°F, so inserting your thermometer into a pot of boiling water and confirming that it registers 212°F sounds like a fairly simple test, right?

In truth, there are a few elements to consider before doing the test; otherwise, you may be testing and calibrating your thermometer incorrectly.

  • Depending on height and air pressure, water boils at various temperatures. The pressure in the atmosphere fluctuates from day to day. Check your altitude, air pressure, and then use this simple calculator to calculate the boiling point.
  • Hard water will boil at 1-20 degrees Fahrenheit higher than soft water.
  • Water cooked in a tall, narrow pot will boil around 10 degrees higher than water boiled in a shorter, wider mouthed pot. To make your life simpler, do the test using a wide-mouthed pot so you don’t have to account for this discrepancy.

After you’ve completed all of your preliminary calculations, it’s time to start the exam.

  1. Pour 4 inches of water into a wide mouthed pot.
  2. Bring the water to a vigorous boil.
  3. Insert the thermometer probe into the water approximately 2 inches. Take the reading after gently stirring the water with the probe for approximately 10 seconds. Make sure the thermometer probe does not contact the edge of the pot, since this can alter the reading.

Remember that if the measurement falls within the manufacturer’s accuracy range, there is no need to calibrate your thermometer.

2. The Ice Bath Test

While the ice bath test is simpler than the boiling water test, it must still be done carefully to guarantee the temperature is accurate. The temperature should be 32 degrees Fahrenheit.

When making an ice bath test, the most essential thing to remember is that a cup of water with several ice cubes floating on top is not an ice bath. If you use this as your ice bath, your results might be up to 12 degrees Fahrenheit too warm.

ThermoWorks has a great guide on properly generating an ice bath:

Creating a Proper Ice Bath

Watch this video on YouTube

Let’s go through how to correctly execute an ice bath test:

  1. Fill a large glass halfway with ice cubes. Crushed ice is preferred since it leaves less holes.
  2. Fill the gaps between the ice with chilled water.
  3. Gently agitate for around 15 seconds to ensure that the temperature is consistent across the bath.
  4. Insert your thermometer probe into the water approximately 2 inches.
  5. Take the reading after gently stirring the water with the thermometer probe for around 15 seconds.

Avoid allowing the probe to contact the glass’s edges, rest on a piece of ice, or settle at the bottom of the cup, since this can alter the reading.

Do not leave your ice bath on the bench for too long before using it. The findings will no longer be accurate if any of the ice at the bottom melts. For the temperature to remain consistent, the ice must cover the whole glass from top to bottom.

How to calibrate an inaccurate Thermometer

If you haven’t previously, you’ll know that your first step is to determine the parameters of your thermometer.

These should come with your thermometer, but you may also get them on the manufacturer’s website.

If you have appropriately checked your thermometer and it is incorrect, it is time to calibrate.

Some thermometers are designed to be calibrated by the user. To do this, see the manufacturer’s instructions. However, some more costly models may need you to contact the manufacturer or ship the item to them for calibration.

Some extremely inexpensive thermometers, on the other hand, will not enable you to calibrate at all.

Keeping a record of calibrations is a good idea. This will help you keep track of how often you have needed to calibrate, and how far off the readings were when you did.

Keeping a record of calibrations is a good idea. This will help you keep track of how often you have needed to calibrate, and how far off the readings were when you did.

Alternatively, you may be able to resolve the issue by changing the probe. Reorder probes for several popular thermometers here:

  • Maverick replacement 3 Ft probe
  • Weber iGrill meat & ambient probe
  • ThermoPro replacement probe
  • ThermoWorks Pro-Series Cooking Probe and Air Probe (for Smoke)

How to Calibrate Popular Thermometers

We’ve included instructions for some of the most common thermometers. However, it is always a good idea to double-check your handbook before doing any calibration. It is a good idea to prepare your ice bath and boiling water tests before beginning the calibration procedure.

Calibrate ThermoWorks Thermapen

  1. Flip your Thermapen around so the rear side is facing you and the probe is facing you.
  2. Remove the Thermaworks tag. This label hides the calibrating screws.
  3. The screw on the right is for zero-point calibration. To calibrate to boiling point, turn the screw to the left.
  4. Remove the probe. This will activate your Thermapen.

Ice Water Calibration

  1. Dip the tip of your Thermapen probe into the ice water and gently swirl without letting it contact the edge of the container holding the water.
  2. Once the temperature has stabilized, spin the Thermapen in one hand to get access to the calibration screws.
  3. Adjust the zero calibration screw with a tiny slotted screwdriver until it reads 32F. After that, you may remove the probe from the water.

Boiling Water Calibration

  1. Dip the probe tip into the boiling water once again, being careful not to allow the probe come into touch with the edge of the pan you’re heating the water in.
  2. Once the reading has stabilized, gently rotate the Thermapen to get access to the calibration screws.
  3. Adjust the screw on the left side (span setting) to 212F.

Time to Double Check

  1. Return your Thermapen to the ice bath. Wait for the temperature to settle before confirming that it is 32 degrees Fahrenheit. Repeat with the boiling water. Continue adjusting the screws as described above until the readings return to normal when the probe is immersed in water.
  2. Replace the lid after everything has been correctly set, and you are ready to use your thermometer again with confidence!

Smoke Calibration:

-1F.While ThermoWorks back the Smoke Thermometerenough to state you shouldnt ever really need to calibrate it, they do say that you can use the calibration function on the unit to fine tune each probe on the Smoke to be accurate within +

If your thermometer reads -4F or above, it is defective. A calibration will not correct this, and you may need to purchase a new probe.-1.8OF. If the reading your Smoke returns is off by +The Smoke comes new from the factory with accuracy to +

If your thermometer reads -4F or above, it is defective. A calibration will not correct this, and you may need to purchase a new probe.-1.8OF. If the reading from your Smoke is off by +The Smoke is brand new from the manufacturer with accuracy to +

  1. Turn on the Smoke and gently swirl probe 1 in the ice bath. Make a note of the temperature measurement after it has steadied. Even though the reading is within the accuracy tolerance, you should be able to make it closer if desired.
  2. Repeat the same steps with the second probe.

Using the Calibration Function

  1. For five seconds, press and hold the CAL button on the smoke control panel. The display should say CAL and the temperature reading should be 0.0F.
  2. Use the up and down arrow buttons to calculate the difference between your reading and the proper value (32F). For example, if the first probe’s measurement was 34.6F, raise it by 1.4F. This will calibrate probe number one.
  3. Press the CAL button to save this for probe 1.
  4. Repeat the procedure for probe 2 by pressing and holding the CAL button and adjusting according to the reading you recorded when you tested the probe.

Time to Test

  • -0.1F.Using the cold bath, test both probes once again. They should both produce readings that are either exactly on 32F or within +

Maverick ET-733 Calibration

Unfortunately, Maverick thermometers cannot be calibrated.

There are a handful of things you can do if your Maverick is incorrect.

  • Perform the ice bath and hot water tests. This will give you the ultimate say on whether or not your Maverick is operating correctly. If you are worried because the Maverick is producing different findings than your smoker’s inbuilt thermometer, chances are the thermometer on the smoker is incorrect, since they are notoriously inaccurate.
  • If it seems that the Maverick is producing incorrect results, check your warranty. Replacement probes or cables may be available.
  • A general reminder: When cleaning the probes, avoid getting water in the areas where the wires touch the probes.

How to calibrate Infrared Thermometers

There are two methods for calibrating an infrared thermometer. However, some solutions are too expensive, so it is comforting to know that a well prepared ice bath would suffice. Let’s have a look at your possibilities.

  • Black Bodies: Industrial calibration lab personnel calibrate infrared thermometers using black body equipment. They are quick and simple to use, and they enable you to calibrate your infrared thermometer to a variety of temperatures with pinpoint precision. They do, however, come at a high cost.
  • Infrared Comparator Cup: A comparator cup is portable and can properly calibrate an infrared thermometer at several temperatures at a significantly lower price.
  • If you don’t have access to a black body or a calibrator cup, an ice bath may provide an accurate temperature of 32 degrees Fahrenheit.

If you wish to calibrate your infrared thermometer using an ice bath, follow the manufacturer’s instructions. We’ve given a broad guidance below to help you understand what could be involved:

  1. As we said in the section, prepare an ice bath. The Ice Bath Experiment
  2. Set your infrared thermometer to 0.95 or 0.97 emissivity.
  3. Hold the thermometer exactly over the ice bath, with the lens perpendicular to the ice bath’s surface.
  4. Make certain that the field of vision just includes the ice bath’s surface. (If the thermometer is held too far away from the ice bath or at an angle, it will take a reading from the glass and be inaccurate.)
  5. To take the temperature, press the button on your thermometer.

Infrared thermometers are regarded to be accurate and trustworthy, thus you should receive a reading of 32F or within the manufacturer’s tolerance limit.

If the reading goes beyond the manufacturer’s indicated range and you are certain you did the test properly, contact the manufacturer.

Tips to Keep your Thermometer Accurate

  • Cooking is a dirty job, so keep the places where the wire meets the probes dry.
  • Manufacturers will generally offer a temperature range in which your thermometer will function. Avoid exposing your thermometer to temperatures outside of this range. You will not only get erroneous findings, but you will also harm your thermometer.
  • When storing a thermometer with cables connected to the probes, avoid kinking or wrapping the cables around the probes. The cable may be damaged as a result of the tension created by kinking and wrapping.

To wrap it up

As we’ve said in several earlier posts, an accurate thermometer is a must-have in every pitmaster’s toolbox.

No matter how much you pay for your thermometer, it is pointless if it is not accurate. Knowing how to test, calibrate, and care for your thermometer is essential knowledge for any BBQ lover.

Do you have any other queries that we didn’t address in this article? Or do you have any thermometer tips or techniques to share? Please share your thoughts in the comments box below. And, if you found this information useful, please share it!


How do you know if a thermometer is accurate?

If your thermometer can indicate temperatures of 32°F or less, the ice bath test is the simplest method to evaluate its accuracy. The benefit of this approach is that regardless of height or air pressure, an accurate thermometer will always register 32°F in a properly prepared ice bath.

Can a digital thermometer be wrong?

A good thermometer is said to be accurate to within 0.3°C. Our best-rated digital probe thermometers deliver on their advertised accuracy of 0.1°C. Ear and forehead thermometers are less accurate in general, but our research revealed that the best models are still accurate to within 0.2°C.

How can I test my digital thermometer?

How to Test a Food Thermometer’s Accuracy
Fill a big glass halfway with ice.
Pour water over the ice and stir thoroughly. Allow to stand for 3 minutes.
Insert the thermometer stem into the mixture at least 2 inches.
After 30 seconds, the thermometer should register 32 degrees.

Do digital thermometers lose accuracy?

The marks on your tape measure or measuring cup do not alter with time, but thermometers may lose accuracy.

Do you add a degree on a digital thermometer?

Thermometers that are digital

At any age, you may use a digital thermometer under the arm and add 1 degree to obtain a rough idea of what the real temperature is (but don’t bank on it being 100% accurate).

What is considered a fever?

When the temperature rises over 99°F to 99.5°F (37.2°C to 37.5°C), an adult most likely has a fever.

Why does my thermometer give me different readings?

Differences in measurements may also be caused by the following factors: The thermometer does not have the same temperature as the room in which you are measuring (for example, it has been in a considerably warmer or cooler room). The thermometer is placed at a variable depth or angle into the ear canal.

Why is my thermometer giving the wrong readings?

Reset buttons are found on many digital thermometers. If the thermometer’s accuracy is off, use this button to adjust it to the correct temperature. Many digital thermometers include removable probes connected to the main body via wire.

How high is too high for a fever?

Adults. If your fever is 103 degrees Fahrenheit (39.4 degrees Celsius), contact your doctor. If you have a fever and any of the following signs or symptoms, get medical assistance right away: A severe headache has struck.

How do I know if my thermometer is calibrated?

With a wrench or other tool, secure the calibration nut and twist the thermometer head until it reads 32 F (0 C). Thermometers should be calibrated on a regular basis to ensure accurate readings. The most common technique for calibrating a thermometer is the ice-point approach.

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