A freezing curve is a temperature-time graph recorded as a product freezes, showing the initial cooling phase, the crystallisation plateau where most water solidifies, and the final drop to target core temperature, used to validate and optimise freezing equipment settings.
In trade practice
Process technologists plot freezing curves during equipment commissioning and after any change in product size or loading density. The critical zone is the crystallisation plateau, where the curve flattens; a prolonged plateau indicates insufficient freezing capacity and predicts poor texture. Curves are recorded using calibrated data loggers placed at the thermal centre of the product. Suppliers may be asked to provide freezing curve records as part of a technical audit.
In a specification
A supplier quality agreement may require that freezing curves be retained for a defined period and made available on request as evidence that core temperature targets were met during production.