Walnuts, the oldest tree food known to man are believed to have come from ancient Persia and were traded between Asia, the Middle East, and far off lands, making the Walnut one of the most popular nuts in the world.

While grown in many countries around the world, California, with its mild climate and deep fertile soils, provides ideal growing conditions for the English walnut, produces 99% of the total U.S. crop and 2/3 of the world’s trade. The walnut is a versatile ingredient nut. In manufactured food products, walnuts positively impact product flavor, texture, mouth feel, nutritional value, and stability. Walnuts are extremely functional in a wide variety of food processes: freezing, baking, broiling and roasting.

Walnuts are sorted into 8 sizes. Walnuts are sized over round hole screens expressed in 1/64î. These sizes range from 12/64î to 52/64.

Shelled Walnuts Packaging Options
As a general rule, pieces and halves are available in 25 lb. corrugated boxes with or without poly-lined bags. Smaller kernel sizes are usually available in 30 lb. boxes. Suppliers also ship in 1,000 to 2,000 lb. containers, #10 tins, and other industrial sizes.

Walnut Halves7/8 or more of the kernel is intact. 85% or more of lot, by weight, are half kernels with the remainder three-fourths half kernels.
Walnut Pieces and Halves20% or more of lot, by weight, are half kernels (7/8 or more of the kernel is intact).
Walnut PiecesPortions of kernels in lot cannot pass through 24/64 inch round opening.
Walnut Medium PiecesAlthough 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 screen.
Walnut Small PiecesPortions of kernels in lot pass through 24/64 inch round openings but cannot pass through a 8/64 inch round opening.
Walnut MealThe smallest form of the walnut comes in various consistencies ranging from a coarse meal to a fine powder. Use walnut meal to dust cakes, use in dough and batter, and for walnut compounds. Finely ground walnut are incorporated into pastas, added to fillings and used as a thickening agent in sauces.
Topping PiecesPortions of lot pass through 20/64 inch round opening.
SyrupersPortions of lot pass through 28/64 inch round opening.

Extra LightNo more than 15% shall be darker than extra light.
LightNo more than 15% shall be darker than light.
Light AmberNo more than 15% shall be darker than light amber.
AmberNo more than 10% shall be darker than amber.

CHANDLERThinLight (about the same as Hartley)48-51%MildPercentage: High
The University of California introduced the Chandler walnut in 1979 and named it after W.H. Chandler, Professor of Pomology, at U. C. Davis. Today it is the most prominent variety grown in California. The Chandler walnut is large, smooth and oval shaped with a good shell seal. Chandlers are known around the world and are highly prized by buyers for their extra light and high quality kernels. Harvested mid to late season, Chandlers provide one of the highest kernel yields of any of the varieties.
HARTLEYHardLight KernelTypically 41-44%Very Good Low
Today this "classic walnut"; is the principal variety marketed inshell. Hartleys are harvested mid-late season. The thin-shelled, well-sealed nut is easy to crack and continues to be the best inshell walnut variety for customers who require an artificially bleached shell.
TULARESomewhat thin, but thicker than ChandlerLight when first shelled, but turns light amberHigh—typically 50-53%High—typically 50-53%Good, though not as high as Chandler or Howard
The Tulare walnut is an increasingly popular in-shell variety, known for its high yield. A newer variety, the Tulare was derived from a tree grown from seed at the University of California walnut breeding program, directed by Eugene Serr and Harold Forde in 1967. Named after a county in California's Central Valley, Tulares are harvested mid-season and continue to be a significant contributor to the state's walnut production.
VINAModerately thickLight Amber46-49%More flavor than Chandler, but less than PayneLow
The Vina walnut is an early to mid-season variety and is popular with growers in the Northern San Joaquin Valley. Vinas are a cross between Franquette and Payne walnuts. The nut is medium to large in size, pointed, and looks similar to Hartley but is less flat on the base. Color is a good tan and the shells are well-sealed. The Vina is well known for its good quality and high yield.

In-shell Walnuts – From the orchard to your table
According to USDA standards “inshell walnuts” are processed in several sizes:


* In-shell walnuts are packaged in 50 lb.

Walnuts should be stored in low moisture (55 – 65% relative humidity) and low temperature (32° – 28° F or 0° – 3.3° C) conditions. Keep walnuts away from excessive heat, moisture, light, and odors to ensure maximum shelf life and freshness