Real Food Encyclopedia | Pistachios
The pistachio (Pistacia vera) isn’t really a nut at all. Technically, it is a “drupe,” a fleshy tree fruit that contains a shell-covered seed. With pistachios we discard the fruit flesh for the tasty seed within. The opposite is true with other drupes such as stone fruits like peaches, cherries and apricots. With those, we eat the fruit flesh and leave the pits, for the most part, behind.
The pistachio belongs to a group of drupes called “culinary nuts” that include cashews and almonds. A real nut, also called a “true nut” or a “botanical nut,” is not a fruit but rather a seed encased in a hard, woody shell. This group includes favorites such as hazelnuts, chestnuts and acorns.
In the United States, pistachios were mainly imported until the mid-1970s when our domestic production found its feet. This was done was through the efforts of botanist William E. Whitehouse, who began importing and experimentally planting pistachio trees in the 1920s. Today, California, where those original plantings were established, is responsible for 99 percent of our domestic production, with the other 1 percent coming out of Arizona and New Mexico. The production of pistachios has exploded over recent decades and the U.S. now produces over 800 billion pounds of the nuts per year, enough to fulfill our domestic market and export product around the world.
Did you know?
- Before pistachios were grown domestically, they were often died red to hide the blemishes they incurred during transport from the Middle East.
- King Nebuchadnezzar had pistachios growing in the hanging gardens of Babylon.
- Because the nuts’ shells open when ripe, they are uniquely susceptible to contamination by the carcinogenic aflatoxin, the toxic product of a mold that is common in a range of foods, including tree nuts. The Administrative Committee for Pistachios regulates 99.9 percent of the pistachios produced in the United States to prevent exposure to this potentially fatal toxin.
What to look for when buying pistachios
On the tree, pistachios are reddish, wrinkled fruits that grow in heavy clusters reminiscent of a bunch of grapes. The husked fruit contains a thin, ivory-colored, bony shell that splits longitudinally along their sutures when mature. Inside the shell is the kernel — what we refer to as the nut. It is about one inch in length and a half-inch in diameter. The kernel ranges in color from yellowish to bright green, the more prized specimens being the more vibrantly hued.
Sustainability of Pistachios
Pistachios are native to semi-arid climates in Central Asia, so they are adapted to long, hot, dry summers like those of California. However, they’re still a water-intensive crop to grow, taking 341 gallons of water per 4 oz serving. Because of their deep roots, this is less than some other nuts like almonds, but they still need a lot of supplemental irrigation from groundwater and limited surface water. Because they’re grown mainly in drought-stressed California, this means that orchards are often in competition with other farms, conservationists, and residents for limited resources. overextraction of water by nut orchards can stress delicate river ecosystems and even make groundwater undrinkable as arsenic and other contaminants seep in.
Like other orchard crops, pistachios are often grown with synthetic pesticides and fertilizers, though many growers use integrated pest management (IPM). In IPM, growers take advantage of beneficial organisms as a first line of defense against pests, allowing them to cut back on pesticide use. If you’re concerned about pesticide use and its impacts on farmworkers and the environment, seek out USDA Organic pistachios.
Seasonality
Harvest takes place anywhere from late August to early October. The nuts are harvested when the husk or hull covering the shell becomes fairly loose. Trees are shaken to release the nuts which fall into mechanical harvesters or onto tarp-covered ground. The outside fruit, or epicarp, must be removed within 24 hours to prevent staining. In large orchards this is done mechanically, but small-scale growers load their freshly harvested pistachios into sacks and roll them around to knock the epicarp from the nut.
The pistachios are then dried either by laying them out in the sun for about two days or by giving them a twenty-minute spin in a commercial drying tank. The nuts are then roasted before being brought to market.
Eating pistachios
Storing
Stored in plastic bags, roasted pistachios will last for about a year in a cool dry place. Nuts go rancid over time, so it’s important to rotate your pantry supply to ensure freshness. Only buy what you will eat within a few months if storing them at room temperature or freeze the nuts for longer storage. Always defrost in their sealed bag before opening to prevent condensation from forming on the nuts. Dampness can invite mold and fungus to contaminate the pistachios.
Cooking with Pistachios
Pistachios can be eaten raw but are rarely available that way, as they are difficult to transport. Commercial pistachios are dried and roasted. You can find them salted and unsalted.
Pistachios are often eaten out of hand and are sold in their shells for snacking.
Shelled, unsalted pistachios are preferred for cooking. They are popular in sweet dishes such as ice cream, desserts and confections, particularly in Middle Eastern and Mediterranean cuisines. They are delicious in savory recipes as well. Try them in grain dishes and salads for a welcome crunch and rich, buttery flavor.
Nutrition
Pistachios have 25 percent of the daily value for Vitamin B6, 15 percent of the daily value for thiamine and phosphorus and ten percent of the daily value for magnesium. They have fewer calories and more potassium and Vitamin K per serving than other nuts. Pistachio nuts contain a substantial amount of fat — 15 grams — per ounce, the majority of which is unsaturated.