In the early 1930s pistachio trees were planted as an experiment in the arid climate of California. A decade of research and breeding resulted in one particularly hearty variety, named Kerman. Commercial cultivation of pistachios expanded across the Central Valley of California by the 1960s. Today there are more than 100,000 acres of pistachio orchards in California, producing in excess of 300 million pounds of this distinct nut. California is the second-largest global producer of pistachios, falling just behind Iran.
Pistachios trees can bear nuts for centuries in alternate-bearing, or biennial, cycles. The crop yield from a pistachio orchard will be heavy one year and light the next, allowing the tree to conserve energy over one growing season for the next big yield. Pistachio trees are abiotic pollinators which means they don’t require animal intervention to pollinate, unlike almonds which rely on bees. Pistachios specifically require male and female trees in the same orchard, and rely on wind to spread the pollen to the female flowers.
Climate also plays a big role in pistachio production. Pistachio trees need approximately 1,000 hours of temperatures at 10 degrees Celcius or below to bring about the dormancy necessary for good production. A mild winter or heavy rainfall during pollination can drastically reduce yield, and improper drainage can result in root rot, essentially destroying a crop or at worst, an orchard. Fortunately, the pistachio variety grown in California is mostly drought-tolerant compared to other North American agricultural crops. Pistachio farmers employ direct irrigation techniques to ensure every drop of water is used wisely.
A pistachio tree begins bearing fruit between the ages of five and seven years. They grow in heavy grape-like clusters, ripening in late summer or early autumn, their hulls becoming rosy and their inner shells splitting naturally along their seams. In the U.S. the majority of pistachios are harvested in September, though elsewhere in the world pistachios are harvested from late August to early October. At harvest time, mechanical “tree-shakers” knock the pistachios onto a catching frame, never allowing them to touch the ground, as the split shell leaves the nut susceptible to contamination. From there the nuts are loaded onto trucks and rushed to the processing plant. Pistachio nuts must be hulled and dried immediately to preserve their delicate quality and to prevent their shells from staining.
Surprisingly, the pest that poses the biggest threat to pistachio orchards is the coyote. When drawn to an orchard with a healthy rodent population, the coyotes get carried away and chew on expensive irrigation lines. To naturally combat the coyote population without resorting to poisons and trapping, a lot of California farmers employ methods to control the rodent population first: owls. Many orchards have resident owls to help maintain a balance in the rodent population ~ control the prey and you control the predators. Owls need a healthy environment to produce healthy chicks. Today’s growers build “owl boxes” in orchards to provide a safe nesting place. Perched atop a high, smooth pole (for good viewing and difficult access for predators), owls can lay multiple clutches of eggs for successive hatchings with a high survival rate. Increasing the population of owls has helped to return a balance between the animals that can damage a crop and their natural predators.
HISTORY and USAGE
Pistachios are native to the Middle East with the first mentions of the fruit dating back as early as 7000 B.C. Similar to almonds, pistachios were a big Silk Road trade item, eventually making their way all over the Middle East, into Asia and Europe. They have a long shelf life, making them a viable trade product where storage options were limited. Pistachios were originally imported to the U.S.A. in the 1880s for Americans of Middle Eastern descent. A staple food of the homeland, it wasn’t until about 50 years later that pistachios were introduced to the rest of America as a snack food, showing up in vending machines across the country. To draw attention from passersby, and to mask any imperfections, pistachios were usually dyed red.
The pistachio was used as a folk remedy for ailments ranging from toothaches to liver sclerosis, and also used as a dying agent. While not quite as revered as almonds, pistachios also play a role in the Bible, used as gifts valued as “the best fruits in the land.” According to Muslim legends, the pistachio nut was one of the foods brought to Earth by Adam, while the Queen of Sheba claimed them as an exclusively royal food and forbade commoners from growing the nut for personal use.
Today pistachios are a common ingredient, lending dishes a bit more of a gourmet flair. They can be used in anything from smoothies and ice creams to dinners and desserts. They’ve been used to crust fish and chicken or even as a delicious nut butter.
Pistachios contain vitamins C and E, powerful antioxidants that help protect the skin against UV damage and improves skin health, hydrating the skin and alleviating dryness. Vitamin B6 is also found in pistachios, 23% of your daily requirement can be obtained in one serving. It has been said that pistachios help the body control insulin levels in the blood, influencing blood circulation and preventing acne breakouts. Pistachios have one of the lowest calorie counts per serving of all nuts, so if you want the heart-healthy benefits from nuts but are conscious of your caloric intake, pistachios may be just the nut for you!