How to calibrate your probe thermometer

Have you every followed one of those “cook to XXX temperature” recipes (you know, like the ones in our weekly meal plans) to the letter, and ended up with an undercooked or overcooked dish?

What the heck?

Let me ask you this…when was the last time you calibrated your probe thermometer?

These little stick thermometers that look so cool in the pocket of a chef’s jacket are also infamous for sliding up and down from “true” zero at the drop of a hat.

This will, of course, give you a false reading, high or low, on your food.

Luckily, it’s pretty easy to test if your thermometer is reading correctly, and even easier to get the little bugger to tell the truth again! Water boils at 212F*, so a probe held in boiling water should read 212F. If it doesn’t, you need to calibrate it.

First: write down how many degrees (plus or minus) your needle is off.

How to calibrate a probe thermometer

Now, turn your thermometer over, and you should find a little hex nut right at the base of the probe. By turning this nut left or right, with a small pair of pliers, you’ll move the needle right or left.

How to calibrate a probe thermometer

This thermometer, which ended up rattling around in the bottom of a gear box for awhile, was reading thirty degrees low (which would make me want to pull my dish off the heat 30 degrees too late…imagine that roast turkey…ugh!) So I let the needle return to room temp, and then turned the nut until the needle reads thirty degrees lower than the original reading at room temp.

Finally, retest your probe, if it now reads 212, you’re done!

How to calibrate a probe thermometer

Seriously, it’s just that easy!

Make sure to test your thermometers on a regular basis, more often the more you use them. Every little bump, and even just regular handling, can knock it off true, and even 5-10 degrees can have a significant effect on your recipe.

Be sure to adjust those thermometers before starting your Thanksgiving feast!

Happy Holidays!

-Chef Perry

*Water boils at 212°F at sea-level.  Each 500 foot increase in altitude causes a drop of about 1° in the boiling point. The reason that water boils at a lower temperature at a higher altitude is because the pressure exerted upon it from the atmosphere is less at higher altitudes and so it is less “held together”.

Check your altitude on this chart, and adjust accordingly.

Approx. Boiling Temperatures of Water
Altitude Temperature
Sea Level 212 degrees F
984 ft. 210 degrees F
2,000 ft. 208 degrees F
3,000 ft. 206 degrees F
5,000 ft. 203 degrees F
7,500 ft. 198 degrees F
10,000 ft. 194 degrees F
20,000 ft. 178 degrees F
26,000 ft. 168 degrees F