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Guide
For most kitchen thermometers, use a well-stirred ice-water slurry and look for 32°F without touching the glass. Adjust only as the manufacturer's instructions allow; some digital models can be checked but not recalibrated.
Fill a large glass with ice, add drinking water and stir thoroughly. Immerse at least two inches of the stem, or the sensing area specified by the maker, without touching the sides or bottom. Wait at least 30 seconds while the probe remains in place; the USDA reference reading is 32°F.
If an adjustable dial is off, hold its calibration nut and turn the dial to the reference point. For a digital thermometer, use its calibration function if one exists. A model that cannot be adjusted may need service or replacement when its error exceeds the maker's tolerance.
Bring clean water to a rolling boil, place at least two inches of the stem in the water without contacting the pan, and wait for a stable reading. The USDA reference is 212°F at sea level, but boiling temperature changes with elevation and atmospheric pressure, so calculate the local value before adjusting.
Check it before first use, after a drop or hard knock, after exposure beyond its rated range, and whenever readings seem doubtful. Food-service rules or an employer's procedure may require a set schedule; follow that local plan rather than assuming one interval fits every kitchen.
Record the thermometer identifier, date, reference method, expected value, observed value and any adjustment or replacement. Clean and sanitize the probe before returning it to food use, following the device instructions and workplace policy.
Common questions
Check before first use and after drops, shocks, extreme temperatures or suspicious readings. Commercial kitchens should also follow the schedule required by their food-safety plan or local authority.
There is no single interval for every jurisdiction and device. Follow the restaurant's written procedure and applicable local food code, with additional checks whenever the thermometer may have been damaged.
The common ice-point method uses a well-stirred ice-water slurry, keeps the sensing area away from the container, and compares the stabilized reading with 32°F. Adjust according to the thermometer manual and document the result.
You can still check its accuracy against a known reference. If the error is outside the manufacturer's tolerance and there is no offset function, replace or professionally service the unit.
Yes, if its range and construction allow it. Correct the expected boiling point for elevation and keep the probe away from the pot's bottom and sides.