Rattleware Thermometer Calibration Tool


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  • Use this handy tool to make sure your thermometers stay accurate.

    Thermometers should be calibrated at least once a week.

    To ensure the accuracy of your thermometers calibrate them often.

    Size: 4in., 10cm


    To calibrate your thermometer, you must use either boiling (212°F/100°C) or freezing (32°F/0°C) water, depending on the range of your thermometer.

    To adjust to boiling water:
    Use a boiling pan of water - remember that the water from your espresso machine is not supposed to be boiling, so don’t use it as a guide.

    To adjust to freezing water:
    In a glass, add crushed ice to cold water until you have a slushy consistency.

    After you have prepared the water, thread the thermometer stem through the hole in the calibration tool. Ensure that the nut on the underside of the thermometer face is aligned with the grooves in the calibration tool. Insert the thermometer into the boiling or freezing water. Turn the nut on the underside of the thermometer face with the calibration tool. This will move the pointer. Align the pointer to 212°F/100°C if you are using boiling water, or to 32°F/0°C if you are using freezing water.

    Your altitude will determine your actual reading - these are for readings taken at sea level.
    For above sea level readings - adjust your temperature using the following chart.

    Elevation / Boiling Point

    Sea Level / 212 degrees F
    2,000 ft. / 208 degrees F
    5,000 ft. / 203 degrees F
    7,500 ft. / 198 degrees F
    10,000 ft. / 194 degrees F