Is Your Thermometer Right?

The holidays are here, and there is lots of cooking going on, at least in my kitchen! One of my most important kitchen gadgets is my meat thermometer, and I have a variety of options. If you haven’t calibrated your thermometer lately (or ever), now is the perfect time to do it. You want to be sure that your holiday meals come out perfectly cooked, not under- or over-done.

Thermometer calibration

Calibrating a thermometer isn’t as hard as it sounds. There are two ways to do it, the cold method and the hot method.

Cold calibration

For the cold method, simply fill a glass with ice (crushed is best). Add water to completely cover the ice. Give it a mix and let it sit for a few minutes. Then pop your thermometer into the ice water. Let the thermometer sit, not touching the sides or bottom of the glass, until the temperature levels off. Your thermometer should read 32 degrees Fahrenheit (0 degrees Celsius).

The digital thermometer in the above picture went down to 33 degrees F, then just read “Lo”. I’m calling that one good.

This analog thermometer in the photo below didn’t do quite so well. In the ice water, it read 40 degrees F. So it needed a little bit of adjustment.

Flip the thermometer over, and look for a nut on the back of the display. This is the calibration nut. You’ll need to turn this nut to adjust the dial.

Before you go hunting for your toolbox, check the thermometer case. Some of them will have a built-in wrench that fits that nut. (Someone was thinking when these were designed!) Simply slide the case back on, and give it a twist. It usually doesn’t take much of a turn to get the dial adjusted.

Then put the thermometer back into the ice water to check the new calibration. You’ll probably have to do this a couple of times to get it just right.

While we’re on the subject of handy thermometer case design, let’s take another look. Almost all thermometer cases have a hole in them, or a clip on the side. This hole or clip has a purpose. Slide the thermometer through, and now you’ve got a handle! It’s not such a big deal when you’re taking the temperature of something cold, but it can sure come in handy when you’re checking the temperature of something hot.

Hot calibration

And speaking of something hot… To use the hot method to calibrate your thermometer, all you need is a pot of boiling water. Use your handy thermometer handle to hold the thermometer in the boiling water, without touching the tip of the thermometer to the bottom or sides of the pot.

You are looking for a temperature of 212 degrees F (100 degrees C). I had to adjust the analog thermometer again. I could either have it read correctly at 32 degrees, or at 212 degrees, but not both. Since I’m going to be using this to measure a turkey’s temperature straight out of the oven, I would rather that it read correctly at the higher temperature.

My digital thermometer never got above 210 degrees F. That’s too bad, because most of these thermometers can’t be calibrated. Check your user’s manual, or call the company to see if your model can be. Usually it ends up being more expensive to have a thermometer calibrated than it is to buy a new one. When the temperature difference is minimal, like it is on mine, it’s probably not a big deal. You can also take this difference into account when you’re cooking.

Since I know that this thermometer reads 2 degrees low, I’ll be looking for my turkey to be fully cooked at 159 degrees instead of 161 degrees.

Have you ever calibrated your meat thermometer? You should be using a thermometer every time you cook meats, not just at the holidays. Take a few minutes tonight and get your thermometer in shape!

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