In the 16th century, a harebrained health theory circulated widely among doctors in Europe: foods that resembled body parts, they believed, were especially beneficial for the health of those parts. A firefly for night vision, red coral to help with your blood, and little old me for the most important organ of all, the powerful human brain.
While walnut trees have been cultivated for thousands of years, the different types have varying origins. The English walnut originated in India and the regions surrounding the Caspian Sea, hence it is known as the Persian walnut. In the 4th century AD, the ancient Romans introduced the walnut into many European countries where it has been grown since. Throughout its history, the walnut tree has been highly revered; not only does it have a life span that is several times that of humans, but its uses include food, medicine, shelter, dye and lamp oil. It is thought that the walnuts grown in North America gained the moniker “English walnuts,” since they were introduced into America via English merchant ships.
Black walnuts and white walnuts are native to North America, specifically the Central Mississippi Valley and Appalachian area. They played an important role in the diets and lifestyles of both the Native American Indians and the early colonial settlers.
China is presently the largest commercial producer of walnuts in the world, with about 360,000 metric tons produced per year. The United States is second, with about 294,000 metric tons of production. Within the U.S., about 90% of all walnuts are grown in California, particularly within the San Joaquin and Sacramento Valleys The annual combined walnut output of Iran and Turkey is approximately the same as the United States, and the Ukraine and Romania are next in line in terms of total walnut production.
Now to pretend I’m a walnut to get a true perspective. It’s true that even the most unobservant of humans couldn’t miss the resemblance, with my meaty folded hemispheres tucked into a protect ive, skull-like shell. And in the end, misguided as their theory proved to be, those scientists got lucky about me. My plentiful polyand monounsaturated fats, along with my enviably high level of omega-3s (I’m the only nut with significant amounts of them), really are essential for cognitive health.
For the record, I’m also a star when it comes to your digestion, given that I’m high in fibre. But humans fell in love with me before science gave me such serious health-food cred. My sweet, quintessentially nutty flavour and delicate texture long ago found me a place among your most delicious comfort foods, dotting your biscuits and cakes, strewn atop sundaes, nestled in brittle or chocolate, and toasted in butter and coated with sugar and spices.
I’m no stranger to savoury indulgences, either, whether puréed into soups and pestos or sprinkled on fresh salads. My light, buttery crunch (which is all the more delightful if you toast me until I’m fragrant) allows me to add just enough texture to a dish to make it interesting without creating a strain on your jaw. You can’t say that about almonds!
Speaking of my more popular (but some might say less fabulous) colleague, you may be interested to know that neither of us are botanically nuts at all – nor are pistachios or cashews, for that matter. A nut features a seed sealed inside a hard outer shell with no flesh on the outside. Think acorns, chestnuts and hazelnuts.
However, if you were to pick me off the tree instead of off the store shelf, you’d see I am the pit inside the green, fleshy layer of my fruit. And the soft stuff you eat is actually the seed inside that pit. If you’ve ever cracked open a peach pit and found an almond-shaped seed inside, you’ll know what I’m getting at.
As tough as my shell can get, delicate oils found within the lobes can go rancid fairly easily. If I’m bitter or lingeringly musty, then we’d best go our separate ways. If you’re not going to eat me right away, put me in the fridge or even in the freezer in a well-sealed, airtight bag.
If you pick my fruit early, before the pit has fully hardened, you can do rather unexpected things. In Britain they pickle me, brining me whole in salt water and preserving me in a brown-sugar-and-spice syrup. With that I become delicate and soft; you can slice clean through me and see the seed, the proto-shell, and the rim of fruit flesh. But what’s really fascinating is the colour of a pickled walnut: black. That’s because my clear, milky juice turns dark when it’s exposed to air.
Young walnut fruit provide that same inky colour to nocino, the Italian after-dinner drink made by macerat ing me in high-proof liquor with sugar and spices. In ancient Rome they would combine my tinted sap with leeches, ashes and charred things to make dark hair dye. My juice was also used to make walnut ink, which Rembrandt, Leonardo and Rubens are said to have used for some of their sketches.
The Encyclopedia of Hair will tell you that in 17th- century England, the oil expressed from my seed was used as a depilatory, thinning the eyebrows and hairlines of women when that look was in fashion.
Now, inexplicably, walnut oil is touted as a baldness cure. Suffice it to say you might be better off not using me for hair-related purposes. But you humans have found countless other applications for me, including employing my shells as an abrasive cleaning agent, used to this day. This was not always a good idea: in 1982, a US Army Chinook helicopter crashed because of gritty walnut-shell residue that had blocked the oil jets lubricating the copter’s transmission.
My favourite inedible function, though, is as an investment vehicle and status symbol. The Chinese regard the finest examples of me the way you might regard jewels or fancy pottery. I can fetch wild sums of money in Asia, where swirling a pair of me in your palm is said to stimulate blood circulation. Matching sets can go for more than $30,000 – the larger, older and of better shape I am, the more I’m worth. Think of that the next time you pop a handful of me into your mouth as a snack. Just don’t bite too hard.
Check out my related post: Have you tried White Rabbit Candy?