Grading means classifying the prunes purchased from the grower by size. The grade corresponds to the number of prunes per 500 grams.

The prunes are graded with a series of perforated metal grids. The perforations in each grid are of identical size and allow only the smaller fruit to pass through.

The grading operation carried out by the handlers enters into the calculation for the prices they pay to the grower for the harvest. To a basic minimum price is added a variable amount based on the appearance of the prunes, their size (grade) and sugar content.