Description: 7/8 or more of the kernel is intact. 85 % or more of lot, by weight, are half kernels.
USDA Size Tolerances: No more than 5 % smaller than three-fourths halves of which no more than 1 % may pass through 16/64 inch (6.35 mm).
2. WALNUT PIECE AND HALVES
Description: 20 % or more of lot, by weight, are half kernels (7/8 or more of the kernel is intact).
USDA Size Tolerances: No more than 18 % shall pass through 24/64 inch (9.52 mm) round hole of which no more than 3 % may pass through 16/64 inch (6.35 mm) and of 3 % no more than 1 % may pass through 8/64 inch (3.18 mm) round screen hole.
3. WALNUT PIECES
Description: Portions of kernels in lot cannot pass through 24/64 inch (9.53 mm) round openings.
USDA Size Tolerances: No more than 25 % shall pass through 24/64 inch (9.53 mm) round hole of which no more than 5 % may pass through 16/64 inch (6.35 mm) and of 5 % no more than 1 % may pass through 8/64 inch (3.18 mm) round hole included in the 5 %.
4. WALNUT SMALL PIECES
Description: Portions of kernels in lot pass through 24/64 inch (9.53 mm) round openings but cannot pass through 8/64 inch (3.18 mm) round openings.
USDA Size Tolerances: 10 % will not pass through 24/64 inch (9.53 mm) round hole and 2 % pass through 8/64 inch (3.18 mm) round hole.
5. WALNUT MEDIUM PIECES
Although not covered in USDA Standards, Medium Pieces are a common size classification used in the California walnut industry. No less than 98 % may pass through a 32/64 inch (12.7 mm) screen. No more than 3 % may pass through 16/64 inch (6.35 mm) screen. No more than 1 % may pass through 8/64 (3.18 mm) screen.
6.WALNUT MEAL (DOUBLE DICED)
The smallest form of the California walnut comes in various consistencies ranging from a coarse meal to a fine powder. Use walnut meal to dust cakes, integrate into dough and batter, and for walnut compounds. Finely ground walnuts are incorporated into pastas, added to fillings, and used as a thickening agent in sauces.