Classification is the basic link of chestnut commercialization, and it is an objective requirement for modern production and commodity economy. Chestnut grading can achieve high quality and good price, meet the needs of different uses and facilitate packaging and transportation.

the northern and southern varieties of chestnut have different uses, and the grading standard can refer to the national industry standard GH/T129-22 (Table 5) or the national standard GB1475-89.

Table 5 Chestnut Grade Standard (GH/T129-22)

* Most large fruits refer to southern chestnuts, with an average of 14 or less per kilogram; Small fruits mostly refer to northern chestnuts, with an average of 14 or more per kilogram; The moisture content of small fruits of all grades is 49% ~ 53%, and that of large fruits is 5% ~ 55%.

Chinese chestnut grading usually adopts manual grading and mechanical grading. Manual classification mainly depends on human eyes, which is simple and easy to operate, but it is influenced by subjective factors and has a large error. Using a classifier in mechanical classification can significantly improve the classification effect, but it is easy to wear the exocarp of chestnut, and the brightness decreases after screening, so it is usually used for pre-selection before chestnut processing. At present, the common practice is to carry out preliminary classification by manual screening at the place of supply, and then classify it with a classifier at the big acquisition point.