Calibrate An Analog Cooking Thermometer With A Cup Of Ice Water

Calibrate An Analog Cooking Thermometer With A Cup Of Ice Water

If you have a standard pocket cooking thermometer you may have noticed it has a hexagonal nut on the reverse side of the dial, which allows for easy calibration. Use a cup of ice water to make sure it gives the correct temperature.

Chef Keith Snow of the local food culinary weblog Harvest Eating suggests that if you don’t have another properly calibrated thermometer on hand to measure your cooking thermometer against you can always fill a cup completely with ice, add water, and stir the ice and water together for a minute to equalise the temperature.

Many pocket thermometers come with protective cases and many of those cases have a small built-in calibration wrench for the thermometer. Place the thermometer in the cup of ice water and adjust the hexagonal nut until the thermometer reads zero degrees C.

Using the ice water method may not give you a perfect laboratory-suitable calibration, but it should be accurate within a degree or two and very suitable for cooking use. If you’ve had the same analogue cooking thermometer for the past decade, you may want to take it out and give this trick a try.

How to Calibrate a Thermometer [Harvest Eating]


  • Shitty idea, unless you’re using the thermometer to measure how cold your ice-cream is!
    Unless you’re living on a hill, I’d have thought calibrating it to a pot of boiling water would be more scientific (ie closer to the actual temperature range you’ll be using the themometer)

    • Because sticking your hand right above boiling water is a *fantastic* idea, right?

      We do this where I work, and it’s accurate enough for most food related things (though make sure the thermometer doesn’t touch the side or bottom of the cup)

    • Except that the temperature of a boiling pot of water is not even over the whole thing. The water at the very bottom of the pot is 100 degrees. The rest of the water is less than 100 degrees. The gas in the bubbles is more than 100 degrees. The pot itself is more than 100 degrees. The differences here are not trivial. I agree that calibrating a cooking thermometer to 0 degrees is not ideal, but calibrating it to a pot of boiling water is worse.

    • Ice water, with a decent degree of certainity ,is 0c degree C. On the other hand boiling water is not that uniform and depends a lot on where in the water you are measuring.

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