How deep must a thermometer be inserted into the ice mixture for calibration?

To accurately calibrate a thermometer in an ice mixture, it is essential to ensure that the sensing area of the thermometer is properly immersed in the mixture to obtain a reliable reading. In this case, inserting the thermometer about 2 inches into the ice mixture ensures that it can effectively measure the temperature of the slush, which is a combination of ice and water at the freezing point (0 degrees Celsius or 32 degrees Fahrenheit).

The depth of 2 inches is sufficient to guarantee that the thermometer's probe is surrounded by the ice and water, allowing it to stabilize and reflect the correct temperature of the ice mixture. If the thermometer is not inserted deeply enough, it may not accurately measure the temperature due to the influence of ambient conditions or insufficient contact with the ice-water mixture. Therefore, this depth is critical for achieving precise calibration necessary for effective and safe food handling practices.