Did you know that you can hear pistachios ripen? We call them nuts, but technically they are a seed. You’ll learn what that’s all about and so much more on the history of pistachios!
Origin of Pistachios
The pistachio is native to Central Asia, in the area that encompasses Iran and Afghanistan. There is evidence that people ate pistachios in this region as far back as 6750 BC in Uzbekistan.
Pistachios were even mentioned in the Bible in Genesis 43:11.
โThen their father Israel said to them, โIf it must be, then do this: Put some of the best products of the land in your bags and take them down to the man as a giftโa little balm and a little honey, some spices and myrrh, some pistachio nuts and almonds.โ But they aren’t nuts. Just one of the many things the Bible has gotten wrong. I said what I said.
Pistachios took on great significance in the ancient Near East where they were preferred by royalty. The Queen of Sheba, a kingdom now part of Yemen and Ethiopia, legendarily reserved pistachios only for royalty to eat.
During the conquests of Alexander in the 330s BC, the Greeks were introduced to pistachios and brought them back to Greece. The same thing happened with walnuts. After a few hundred years in Europe, the Roman Emperor Tiberius brought the pistachio to Spain and Italy.
But it was the rise of Islam in the 600s AD that expanded the trade and cultivation of pistachios and the nut grew in popularity during the Middle Ages. It remained a rarity in the European interior until trade networks opened after World War II, when it became a popular snack.
California Pistachios
More than 99% of all pistachios grown in the US are grown in California. The remainder are grown in New Mexico and Arizona.
The pistachio was introduced to the U.S. in 1854 by seed distributor Charles Mason. Mason was known for providing experimental seeds throughout California, Texas, and other southern states. The first pistachios trees were planted around Sonoma, California in 1881. For decades, the pistachio remained more of a curiosity than a actual crop in California. Academics, farmers, and the government saw the potential for pistachios to grow there but struggled to find a variety that worked in the climate.
The US Dept of Agriculture set up a research station in Chico in the early 1900s to find out how to grow pistachios in California. This is also where they figured out growing kiwifruit. Their efforts culminated in an expedition to Iran led by botanist William E. Whitehouse in 1929. There he gathered several varieties of pistachio seeds and test-planted them back in California. One variety, the โKermanโ, grew well and began to be distributed around the state.
That makes it sound easy. Pistachio trees take some time to grow and produce fruit. It was quite a few years before Whitehouse knew if he had succeeded.
American Popularity
Pistachios were initially popular with the country’s Middle Eastern immigrants around the 1880s. And thanks to vending machines installed in underground train stations, bars, and other common locations, by the 1930s, the rest of America caught on. By the 1960s wide-scale planting in California began and even spread to Arizona and New Mexico. The first commercial crop of pistachios came out of California in 1976.
Most of Californiaโs pistachios are grown in the San Joaquin Valley. Kern, Madera, Fresno, Kings, and Tulare are the predominant growing counties. There are over 300,000 acres of pistachios planted in the Golden State. California saw a boost to the number of pistachio farms in the state due to the Iranian Revolution of 1979. After the revolution, the U.S. embargoed Iranian pistachios – who was a huge producer – and California picked up the slack.
Changes to the tax code also helped. Tax shelters for almonds and citrus fruits had been eliminated, which further encouraged farmers to invest in pistachios. Pistachios were still eligible for such tax breaks.
How Pistachios Got Their Name
The use of the word pistachio in English goes back to the 16th Century when English speakers borrowed it from Italian, “Pistacchio.” Before that, we used the Old French word โPistaceโ.
The Italians got the word from the Medieval Latin โPistaciaโ which was influenced by the Ancient Greek โPistakionโ which was influenced by the Persian โPistakeโ. Pistake in Persian simply means pistachio.
Biological Species
Pistachio trees belong to the species Pistachia vera. Pistachios are in the Cashew Family (Anacardiaceae) which also contains mangoes and poison ivy. Fun fact: this is why some people have a poison ivy like reaction to mangoes. Maybe fun is the wrong word.
The pistachio is a culinary nut, not a botanical nut. This is because the shell opens naturally to reveal the seed, while with true botanical nuts that doesnโt happen. Botanical nuts include hazelnuts, chestnuts, and acorns.
The full pistachio fruit (husk/hull, shell, and seed) is a drupe. That is a stonefruit like a cherry, peach, plum, or nectarine. A drupe is defined as a fleshy hull that surrounds a shell that encases a seed. In the case of pistachios, the flaky part is the hull and in peaches, the hull is the flesh of the peach that we eat.
Pistachio Varieties
Kerman is the most popular variety in California and the industry standard in American markets. But other varieties are grown. Some varieties split open more reliably, some are larger, and some give larger yields. There are even different varieties of male pollinator trees but they do not produce.
- Kerman
- Golden Hills
- Lost Hills
- Gum Drop
Pistachio Nutrition
Pistachios, like many tree nuts, are very nutritious. They have a similar protein content to salmon. They have four times as much fiber as broccoli. Pistachios are also very high in potassium, with three times as much as a banana.
Eating Pistachios
Most pistachios are sold with the shell removed. About 83% are sold without the shell, and 17% are sold with the shell still on.
Most pistachio consumption takes the form of salted, roasted snack food. For the pistachios that are not fit for sale as whole nuts, they are sold as ingredients. They go into candies, baked goods, ice creams, confectioneries, and flavorings. Theyโve also increasingly been used in savory applications like sauces and dressings. Pistachios are also consumed as a paste or oil.
Some popular options include the Mediterranean pastry baklava. Pistachios are also added to biscotti and mortadella in Italy. It is used to flavor dairy products in India.
History of Red Dyed Pistachios
Do you remember when pistachio nuts were dyed red here in the U.S. This was done by Middle Eastern importers to cover up imperfections in the product. It also made them stand out on the shelves. As production grew here in the U.S., American producers and growers also adopted the dying habit. Keep in mind, U.S. production picked up due to the embargo on Iranian pistachios. However, over time the practice of dying them just faded out.
Global Production
Global production of pistachios sits at around 1 million tons. The United States is the leading producer of pistachios by far with around 40% of global production. After the US, Iran and Turkey are also major producers. They share around 50% of the worldโs production of pistachios. Other growers include China, Syria, Madagascar, Tunisia, Afghanistan, and Iraq.
Farming Pistachios
California is the ideal place to grow pistachios. The following conditions help pistachio growers succeed.
Water & Soil
Trees prefer well-drained soils. They do not tolerate prolonged periods of wet soil. They are very drought-tolerant and only require irrigation every few weeks during dry summers. Drip irrigation is ideal.
Planting
Commercial plantings are usually 120 trees per acre. Trees are planted in rows to make it easier for the harvesting machines. They begin to produce nuts the 4th year after planting, reach good production after 8 years, and full maturity after 15 years. The average yield per tree is 20 pounds at maturity. Pistachio orchards in California can be productive up to 100 years. Trees can live to be 300 years old.
Planting is usually done with small saplings from nurseries. Saplings are typically good fruiting scions grafted onto disease resistant rootstocks. Planting should be done in spring so the trees have time to grow stress-free over the summer and get settled into the soil.
Pistachios come in male and female trees. To produce nuts, an orchard must have some male trees to pollinate the female ones. Generally, one male tree is planted for every 24 female trees. The pollen is spread by wind.
Maintenance
Fertilizing helps with young trees. Nitrogen is the key element along with potassium and phosphorus if needed.
During the second year of growth, itโs helpful to train the tree to be the shape you want it to be. Pruning should be done in late winter or early spring and helps produce healthy crops. Dead branches and suckers are generally removed, as are tips to stimulate growth. Male trees donโt need to be pruned.
Growing Season
Pistachios grow in grape-like clusters containing about 50 nuts. The trees are dormant during the winter, from December to February. After, the trees flowers begin to bloom as the weather warms in March. Pollination continues into April and the bud turns into a nut by May. The nut continues to harden and the edible seed develops in June. The nut grows over the summer rapidly and the seed splits the shell by late August in preparation for the harvest in September.
During the ripening process, the grape-like clusters, turn from green to yellow to red. What you see changing color is the hull or exocarp of the fruit. When they are red, they are ready to harvest. About a month prior to harvest, the shell containing the seed, that is encapsulated by the hull, it splits open keeping the hull intact.
In fact, you can hear pistachio nuts ripening as they make an audible pop. Hearing such a sound was considered good luck by some cultures.
If not harvested, the pistachio will fall from the tree. Eventually the hull will deteriorate and the kernel — the seed we eat — will germinate and sprout, breaking through the shell.
Harvest
Harvesting pistachios takes two different machines. One is a shaker-catcher. There is a Taylor Swift joke in there somewhere. It drives along one row, presses up against the tree, shakes it, and the pistachios fall off onto its catcher part. The next machine is a catcher-conveyor. It drives along in the opposite row. This also catches the nuts and funnels them to a conveyor that brings them to a waiting cart.
Harvest occurs from late August to early October.
Processing
The hulls need to be removed soon before their degradation discolors the shell. Large operations have grinders/abraders to detach the hulls from the shells. They are then washed, dried, and separated by size. That drying process is key to not over-drying the nuts.
Nuts that have not opened naturally are then sorted out along with any others that may have problems. 70-90% of pistachios open naturally, the rest are run through a shelling machine. Shelled pistachios go to baking and other confectionery uses. The nuts are then roasted and packaged for sale.
And thatโs how pistachios got from Iran to California, to you!
Sources: UC Davis California Pistachio Paper, Wikipedia Pistachio, Ag Marketing Center – Pistachio Brief, Keenan Farms, American Pistachio Growers History, Anacardiaceae Wikipedia Page, Heart of the Desert Info Page, Keenan Farms Processing Page, Wikifarmer Pistachio Guide, Sierra Gold Nurseries, Rootstock, FDA Pistachio Pamphlet, How stuff works on Pistachios, Pistachio Harvesting Video, Pistachio Growth Cycle
