How do I check a thermometer in ice water or boiling water?

Fill a glass with crushed ice and water (or bring a pot to a rolling boil), put the probe in, wait for the reading to settle, then open the Calibration module on the tablet.

1. Tap the thermometer: it moves to the "To validate" panel.
2. Pick the bath: "Ice water · 32 °F" or "Boiling water · 212 °F".
3. Set the value shown on the thermometer, to the tenth. The tablet shows "gap +0.2 °F · Compliant" right away, in green as long as the gap stays within tolerance.
4. Add a "Note (optional)" if useful, pick the name under "Who", then "Validate". Several thermometers can be checked one after the other with a single validation.

The thermometer tile then shows "checked on" with the date, the gap, the verdict and the date of the next check. No Wi-Fi? The check goes out on its own when the connection is back.

Tip: the ice-point method is the one the FDA Food Code describes and the most reliable, as long as the glass is packed with ice and the probe touches neither the bottom nor the sides. Boiling water only reads 212 °F at sea level: at altitude, stick to ice.