Walnuts may be the oldest-known cultivated tree crop, but until recently, I had little idea as to how the actual harvesting and processing procedure goes down. Thankfully, the California Walnut Board and Commission  invited writers to the Mariani Nut Company's  orchards and processing plant to better understand the journey each walnut makes from the tree branch to your plate. Click through to be enlightened and inspired.
Walnuts on the Tree
The walnut harvest season in California typically runs from late August through late November. Once the outer green hull of the walnut begins to dry and split (as pictured), the nuts are ready for harvest.
Shaking the Walnuts Off the Tree
The orchard floor is swept for debris, and then a mechanical shaker is employed to vigorously shake each tree trunk, knocking the ripe walnuts off their branches and onto the cleared orchard floor.
Thanks to their sturdy shells and leathery outer husk, walnuts are exceptionally well-protected from pests and rot. If stored and handled properly, they can even be consumed up to one year after harvest, although they're generally consumed much earlier.
A separate machine is used to sweep the walnuts into neat rows so that mechanical harvesters can pick them up off the ground efficiently.
Walnuts Fresh From the Tree
When consumed fresh from the tree, walnuts have a softer texture and a creamy, slightly bitter flavor. At this stage, they typically have a 20- to 25-percent moisture level. After the walnuts are cleaned and the leathery outer husk is removed, one of the first processing steps these walnuts will undergo is a mechanical drying process. Even those walnuts sold in shell will be dried to achieve an 8-percent moisture level, which results in a snappier and nuttier nut familiar to consumers' palates and also protects the nuts from rot.
Cracking the Shells
While a little less than half of exported walnuts are sold in-shell, only about 5 percent remain in shell stateside. The other 95 percent are cracked to order, as storing the nuts in their shells extends their shelf life.
Sorting by Size
After being initially screened for any debris, the kernels are air-separated from the cracked shells and sorted into a variety of sizes and colors. Generally speaking, lighter-colored intact halves sell at a premium, while smaller darker pieces are sold at a lower price.
California's standards for walnut quality are extremely stringent; pictured here are two workers inspecting the processed nuts to ensure that they are clean, properly dried, and of the correct size and color for the particular order at hand. After this step, the nuts will be packaged and shipped off.
Testing the Batch
Additionally, a small sample is removed from each batch and will undergo chemical and microbiological laboratory tests to ensure that they meet all food safety regulations set forth by the California Walnut Board, the USDA, and the FDA.
This year's California walnut crop is shaping up to be the third-largest harvest on record: an estimated 495,000 tons! This is great news, as the California walnut industry accounts for more than 99 percent of the commercial US supply as well as about three-quarters of the global trade.
To the Plate
The walnuts eventually make their way from the processing plant to the kitchen and, finally, to the table. We dined on a variety of walnut-bolstered dishes dished up by Buckhorn Catering , in honor of the harvest.
The menu included a velvety pureed butternut squash soup topped with a dollop of crème fraiche and toasted walnuts, as well as roasted salmon with dill sauce, penne with roasted seasonal vegetables and toasted walnuts, and a persimmon galette topped with (you guessed it) walnuts.
Feeling inspired? Take a cue from these creative uses of walnuts, or employ them in a variety of other delightful dishes .