Calibration Log

A calibration log is a written or digital record of checks performed to confirm that a measuring instrument, such as a food thermometer, is accurate enough for its intended use. In a professional kitchen, the log helps demonstrate that temperature measurements can be trusted when receiving, cooking, cooling, holding and storing food.

What to record in a calibration log

• Date and time of the check.
• Thermometer or instrument identification, including a unique number if the kitchen has several devices.
• Calibration or verification method used, such as an ice-point check or another suitable reference method.
• Observed reading and the expected reference reading.
• Acceptable tolerance or pass/fail result, based on the instrument and food-safety procedure.
• Adjustment made, if the device is adjustable, and the reading after adjustment.
• Name or initials of the person completing the check.
• Corrective action if the instrument is inaccurate, damaged or unsuitable for use.

How kitchen thermometers are checked

A commonly used field check is the ice-point method: prepare a well-mixed slurry of crushed ice and clean water, place the probe in the mixture without touching the container, allow the reading to stabilise and compare it with the expected reference temperature. Use the manufacturer’s instructions and the operation’s procedure for probe placement, stabilisation and acceptable tolerance. Other instruments or temperature ranges may require a different reference method.

What happens when a thermometer fails?

Remove an unreliable device from service or clearly identify it as not for use until it has been corrected or replaced. If food-safety decisions were made using a suspect thermometer, assess the affected products and records, recheck temperatures with a verified instrument where possible, and follow the corrective-action procedure.

Why the log matters

A consistent record supports food-safety verification, equipment maintenance and traceability. It also helps managers identify recurring problems with a particular thermometer or staff procedure.

Example: A cook checks a probe thermometer using the kitchen’s ice-point procedure, records the instrument ID and observed reading, and documents the corrective action when the reading falls outside the established tolerance.

Chef’s tip: A calibration log is only useful when the check is performed correctly and the instrument is suitable for the measurement. Keep the procedure, reference method and acceptance criteria available to staff.

Key distinction: Calibration establishes or adjusts measurement accuracy against a reference. A routine verification check confirms that an instrument remains within the required tolerance.