California Walnuts | Essential Food for Health

History

Walnut History & Lore

While many believe walnuts first grew in Persia, excavations in southwest France have revealed petrified shells of walnuts roasted during the Neolithic period, more than 8,000 years ago.

The very name of the walnut tree and its nut originated with the Romans. The Romans called walnuts Juglans regia, “Jupiter’s royal acorn.” Walnuts have been discovered in prehistoric deposits in Europe dating from the Iron Age. Remains of husked, well-preserved, unbroken walnuts were unearthed in the ruins of Pompeii, the ill-fated city instantly petrified in the cataclysmic eruption of Mt. Vesuvius in 79 A.D.

Interest in walnuts and health started in the 16th and 17th centuries when the medical profession adopted the Doctrine of Signatures, which said that various plants were effective as herbal medicines due to their resemblance to particular body parts. The outer hull of the walnut was used to treat head-related ailments. Eating walnuts was thought to boost the intellect and soothe emotions because of its striking resemblance to the brain and heart, depending on the way the walnuts were cracked. Today, cutting edge health research is proving many of these beliefs are true!

Early Days of the California Walnut Industry

The first commercial walnut plantings began in 1867 when Joseph Sexton, an orchardist and nurseryman in the Santa Barbara County town of Goleta planted English walnuts. For several years, walnuts were predominantly planted in the southern areas of California, accounting for 65% of all bearing acreage.

Some 70 years after Sexton's first planting, the center of California walnut production moved northward to the Stockton area in one of the most dramatic horticultural moves in history. Better growing areas, improved irrigation, and better pest control methods in the north resulted in greater yields, which gradually increased each year.

The California Walnut Industry Today

The Central Valley of California is now the state's prime walnut growing region. Its mild climate and deep fertile soils provide ideal growing conditions for the California walnut. California walnuts account for 99% of the commercial US supply and two-thirds of world supply.

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Cultivation

Walnut Varieties

There are over 30 varieties of walnuts grown in California; however, two varieties—Chandler and Hartley—account for nearly 60 percent of total production.

Table of Varieties

Walnut Orchards

Commercial walnut orchards are located throughout the Central Valley of California and in Coastal Valleys, from Redding in the north to Bakersfield in the south. Current walnut acreage in California has reached nearly 220,000 acres!

After an orchard is planted, it takes approximately four years until it produces its first major crop. Constant attention is given to each tree every step of the way—from pruning, spraying and fertilizing to irrigation—to ensure a healthy orchard. Once a walnut tree has been planted and stabilized, it will continue to bear fine quality fruit for as long as a century.

Walnut Harvest

In late August, boughs of California walnut trees hang heavy with walnuts, protected by nature in thick green hulls. The harvest begins in late August when the protective green hulls split, signaling that the nuts are ready to be removed from the trees. Harvesting methods used depend on the size of the orchard and the equipment and crew available to the grower. The harvest season usually continues into early November.

Harvesting operations are largely automated. First the orchard floor is rolled or dragged clean of twigs, rocks and other orchard debris. Then the nuts are removed from the tree by a mechanical shaker. After they have been shaken to the ground, walnuts are blown into a row to allow mechanical harvesters to pick them up for cleaning and hulling.

Drying

After hulling and washing, the nuts are transferred from the mechanical harvester into a hopper where they are mechanically dehydrated (air-dried) to the desirable 8% moisture level. This prevents deterioration of the nut and protects its quality during storage. Mechanical dehydration—quick, thorough and scientifically controlled—represents a major improvement over the sun-drying method formerly used.

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Processing

Processing

After drying, walnuts are loaded into trucks and transported to nearby packing plants.

Inshell Walnuts

Walnuts with desirable traits such as big beautiful shells are selected for the inshell market. The walnut is cleaned, dried and readied for markets around the world where holiday cracking of walnuts is an age-old tradition. Sizing of inshell walnuts is conducted according to USDA standards. Inshell walnuts are sized as "Jumbo", "Large", "Medium" or "Baby."

Shelled Walnuts

Clean and dried walnuts are stored until ready to be cracked by state-of-the-art equipment to produce what are called "shelled" walnuts, which also mean shell-removed. Only top quality walnuts enter the processing channels, and all aspects of California walnut processing is done to exceed the world's highest food processing sanitation and quality control standards.

Walnuts for both consumer and industrial use are removed from storage as needed and sent to a shelling department where they are cracked. Cracking is done mechanically.

Next the shelled walnuts are screened, separating kernels into a series of sizes. Then kernels are air separated to remove shell fragments.

By bucket elevator and conveyor systems, the kernels are then moved to electronic color separators and laser sorters. Finally, the walnuts are hand sorted by trained inspectors for quality and are ready for packaging in clear film bags, or bulk cartons.

Quality Standards

All walnuts must meet or exceed the standards set by the USDA for inshell and shelled walnut kernels as outlined in the Federal Walnut Marketing Order. The DFA of California certifies all outbound walnut shipments of both inshell or shelled walnut kernels to meet USDA standards. This is your assurance that California walnuts are the world’s finest!

Packaging

California walnuts are produced in a wide range of sizes, color grades and combinations of sizes and colors to meet the specifications of walnut buyers for industrial, foodservice and retail customers.  Consumers can find inshell walnuts as well as walnut halves, halves and pieces and chopped walnuts in supermarkets and club stores across the country.

Walnut Shipments

California walnuts are shipped to over 40 countries around the world each month. Domestic customers receive about two-thirds of the shelled walnut shipments while export markets receive about 80% of the inshell walnut shipments.

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