Taking into account the similarities of broken-line heating curves and heat-penetration curves obtained when a product undergoes a drop in rotational speed during thermal processing in a rotary water cascading retort, a semiempirical method used for handling broken-line heating behaviour is suggested as a method of dealing with this type of process deviation. For this purpose, the possibility of extrapolating the empirical heating rate parameter f(h), determined on the heat-penetration curve of white beans in brine processed in a still retort to the ＇still＇ conditions associated with a rotational speed drop in a rotary water cascading retort, was investigated. Following this approach, safe product temperature predictions were obtained. The main criterion influencing the quality of the evalution was the determination of the correct empirical parametric value to be used. This means when determining this parametric value, care is required when selecting the correct temperature interval on the heat-penetration curve.