What is the correct method for calibrating a pyrometer?

To properly calibrate a pyrometer, the most effective method is to fill a cup with ice and cold water. This technique utilizes the freezing point of water, which is a stable and easily reproducible temperature reference point. Ice water should ideally be at 32°F (0°C), making it an excellent standard for calibrating temperature measurement devices.

When calibrating, the pyrometer's readings should match this known value. If the pyrometer shows a temperature significantly different from 32°F when placed in the ice water mix, it indicates that recalibration is necessary. This method is widely accepted in food safety practices because it ensures the accuracy of temperature readings critical for food storage and preparation, thus helping to prevent foodborne illness.

The other options do not provide reliable calibration methods for a pyrometer. Boiling water, while it indicates the boiling point, varies with altitude and can cause inaccuracies. Using a hot pad to cover ice does not establish a standard temperature point and can lead to unreliable data. Measuring temperature directly in steam introduces variables that can also affect the accuracy of the reading, making it unsuitable for consistent calibration.