2.1 What is yield loss?

Yield loss describes the change in the mass of an ingredient during processing. In cooking, two types of yield loss are of primary importance:

1. Trimming loss: What is lost when bones, sinew or skin are cut away. For example, the bone content of a bone-in chicken breast is approximately 15–20% of total weight.
2. Cooking loss: Weight loss during cooking caused by water evaporation, rendered fat or dissolved proteins. When meat is roasted or simmered, an average of 25–40% of the initial mass is lost.

Additional factors include biological variability such as processing uncertainty and the water-binding capacity of meat, as well as direct trimming such as the removal of scales and fins from fish. Yield loss has wide-ranging consequences: the true cost of the ingredient rises and the number of usable portions decreases.