When ripe, the shell opens partially to reveal the nut inside. Middle Eastern cultures think it resembles a smile and dubbed them, "the happy nut". The flavor has been described as rich and a little earthy with a touch of sweetness. Highly nutritious, some say the pistachio is the world's greatest nut. They're definitely in the running in my book.
Pistachios have a long history and are one of only two nuts mentioned in the Bible. Archaeological discoveries have revealed that pistachios were a common food as early as 6750 BC. In Ancient Persia, now modern Iran, ownership of pistachio groves signified wealth and high status. Legend says pistachios were a favorite of the Queen of Sheba, who kept all the harvests for herself and her court. I certainly wouldn't blame her for that. Following the conquests of Alexander the Great in 334-323 BC, the nut arrived in Greece. Under the rule of the Roman Emperor Tiberius in the First Century AD, pistachios were introduced into Italy.
When is a nut not a nut?
Botanically, the pistachio is not a true nut. It's the edible seed of the pistachio tree. Like many other seeds used for culinary purposes, they're considered to be nuts, and are also classified as a tree nut allergen.
The pistachio (Pistacia vera), a member of the cashew family, is an appealing small tree that produces the famous seeds eaten around the world. As pistachio trees mature, the smooth, pale-gray bark darkens and cracks. The distinctive wood ranges from pale olive to orange-or-purplish brown and displays striking irregular brown or black graining. It's used to craft musical instruments, inlays, carvings, knife handles, and turned objects. The wood of these trees is uniquely beautiful and not often seen made into items such as those below.
(Arizona pistachio wood lazy Susan and wine stopper photos are courtesy of Queen Creek Wood Crafters and used with permission.)
Pistachios on the move
The nuts traveled from Syria to Italy during the first century AD, and from there, spread throughout the Mediterranean region. They were vital necessities for early traders and explorers due to their exceptional nutritional value and long storage life. Pistachios were frequently carried by travelers on the ancient Silk Road connecting China with the West.
The Venetian Republic had close trade ties with Syria, one of the main cultivation areas for the pistachio. Syrian exports reached northern and central Italy via maritime trade routes. North of the Alps in Italy, the pistachio remained unknown for a long time. After reaching Central Europe, pistachios became known as the Latin penny nut.
By the time they were regularly imported into Europe, they had become quite expensive and unaffordable for many people. However, merchants in France maintained an ample supply of the popular commodity for their wealthy customers.
North of the Italian Alps, pistachios were used early in cooking, primarily as an expensive addition to baked goods. Only after World War II did the pistachio's reputation gradually change from expensive baking ingredient to popular snack.
(Photo: Willis Lam, CC BY-SA 2.0, via Wikimedia Commons)
They're featured in a 5th Century recipe book!
In the First Century A.D., Emperor Vitellius introduced Rome to the pistachio, and in the 5th Century A.D., a manuscript titled De re culinaria contained a nut tart recipe using pistachios. If you'd like to give it a try, here it is. But as the Romans say, caveat emptor! Or at least look before you leap.
400g crushed pistachios
200g pine nuts
100ml dessert wine
100ml full-fat sheep’s milk
1 teaspoon fish sauce
1. Put the chopped nuts and whole pine nuts in an oven-safe dish and roast until golden.
2. Turn oven to 400°F. Meanwhile, mix the honey and wine in a pan and bring to a boil, cooking until the wine has evaporated.
3. Add the nuts and pine nuts to the honey and cool.
4. Beat the eggs with the sheep’s milk.
5. Add the fish sauce and pepper.
6. Stir the honey and nut mixture into the eggs. This will be extremely difficult to accomplish due to the sticky, rock-like consistency of the nut mixture.
7. Oil an oven-safe dish and pour in the nut mixture. Cover the dish with foil and place in a roasting pan filled ⅓ deep with water.
8. Bake for about 25 minutes until the mixture is firm. Remove from oven, cool to room temp, and chill in your handy well shaft or refrigerator. (To keep food cool, the Romans are thought to have prepared well shafts they filled with snow and ice during the winter and topped with straw insulation.) Personally, I'd go with the fridge.
To serve, tip the tart onto a plate and drizzle with boiled honey.
If you tried this recipe and are now exhausted, keep in mind the Romans relied on slave labor. So relax, put up your feet, and have a glass of Chianti. You've earned it!
Why pistachios are green and other nutty facts
This colorful nut gets its green and purple colors from antioxidants. The red pistachios you sometimes see during the holidays are artificially dyed. I had assumed this was done to make them more festive and appealing for the holidays. Not so. When the U.S. imported most of its pistachios, the shells would often arrive splotchy and unattractive. Dying them concealed the stains. Today, roughly 98% of pistachios sold in the U.S. are grown here, and a mechanized harvesting process ensures they are picked, hulled, and dried before the shells can become stained.
A preliminary behavioral eating study showed that in-shell pistachio snackers ate 41% fewer calories than those who ate shelled nuts, an effect known as The Pistachio Principle. This hypothesis states that consumption of unshelled pistachios may help slow eating because leftover shells offer a visual cue to the amount eaten, resulting in a possible reduction in caloric intake.
Scientific evidence suggests that eating 1.5 ounces per day of most nuts, including pistachios, as part of a low-fat diet may help reduce the risk of heart disease.
The shells can be recycled as drainage chips in pots and planters, and as mulch around garden plants. Snails avoid the sharp edges.
Pistachio shells make good kindling for enclosed fire pits and wood stoves. To start or revive a fireplace fire, toss in a handful of pistachio shells. Initially, they will crackle and hiss loudly due to the high oil content.
Pistachio nuts can self-ignite! This is only a concern when large amounts are shipped in cargo trucks or semi-trailers.
In 2014, Turkey began making plans to fuel a town entirely with pistachio shells.
How will you celebrate National Pistachio Day?
Snack on the nuts throughout the day.
Include pistachios at every meal.
Use them in a new recipe, such as these Pistachio Lemon Truffles.
Make homemade pistachio ice cream!
Pistachio trees need long, hot, dry summers and winter chilling, but won't tolerate frozen ground. During dormancy, they require approximately 1,000 cumulative hours of temperatures at or below 45°F. The environment must be arid. Pistachio trees will not thrive in high humidity.
Not only do pistachios pack a nutritional punch, they pack a sizeable economic punch as well. According to the American Pistachio Growers website, the states of California, Arizona, and New Mexico represent 100% of U.S. commercial pistachio production. There are 950 producers in the United States, and the annual farm gate value of pistachios adds more than $1.6 billion to the California economy and more than $16 million to the states of Arizona and New Mexico.