Shelled walnuts (Juglans regia) can be graded based on USDA criteria.
Current grades:
(1) No. 1
(2) commercial
In 1976 there were additional grades No. 2 and No. 3.
Quality factors used to grade:
(1) dryness
(2) decay
(3) discoloration
(4) rancidity
(5) insects
(6) mold
(7) shriveling
(8) shell
(9) foreign material
Color references: extra light, light, light amber, amber (dark brown), red
Classification of kernel size in a product:
(1) half-kernels (halves): > 85% by weight
(2) pieces and halves
(3) pieces
(4) small pieces (able to pass through a sieve with round openings 24/64 inches in diameter)
