Almond

• 1. Introduction

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  Each February, more than 1 million beehives are loaded onto trucks and driven across the United States to a single crop in California. That is nearly half of all the beehives in the country, summoned for one task. The crop is the almond, and the gathering is the largest annual managed pollination event in the world. Behind that strange migration lies a fruit that most people misname. The almond is not a nut. It is a drupe, a stone fruit kin to the peach and the plum, and the part we eat is its seed. This is the story of a tree that humans tamed before they could even graft, that turned a recessive gene into a global crop, and that carries enough cyanide in its bitter form to kill a child. It is also a tree that demanded so much water it may have outgrown the land that grows it. How did a wild, often poisonous seed become a food found in marzipan, milk substitutes, and the menorah of the Holy Temple?

• 2. Not A Nut

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  The thing inside the shell is a seed, though almost everyone calls it a nut. Botanically the almond is a drupe, the same fruit structure as the plum and cherry. Where those fruits give a juicy flesh, the almond's outer covering is a thick, leathery, grey-green coat with a downy exterior, called the hull. Inside the hull sits a woody endocarp that hardens into a reticulated shell, like the surface of a peach pit, called the pyrena. The corrugations on that woody shell are what set the almond and the peach apart from the rest of the genus Prunus. They share a subgenus, Amygdalus, defined by exactly that wrinkled endocarp. Inside the shell is the edible seed. Usually there is one, though occasionally two occur. When the fruit matures in autumn, seven to eight months after flowering, the hull splits and an abscission layer forms between the stem and the fruit, letting it fall. The deciduous tree itself stays modest, reaching three to four and a half metres tall with a trunk up to 30 centimetres across. Its fragrant white to pale pink flowers, three to five centimetres wide, open before the leaves in early spring, a head start that defines the entire harvest calendar.

• 3. Tamed From Seed

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  Almonds were one of the earliest domesticated fruit trees, and the reason is a quirk of their biology. They produce quality offspring entirely from seed, without suckers or cuttings, so their cultivation may have predated grafting altogether. Domesticated almonds appear in the Early Bronze Age, between 3000 and 2000 BCE, at sites such as Numeira in Jordan, or possibly earlier. They were found in Tutankhamun's tomb in Egypt, around 1325 BCE, probably imported from the Levant. The wild ancestor used to breed the domesticated species is unknown, though Prunus fenzliana is considered the most likely candidate, native to Armenia and western Azerbaijan where it was apparently domesticated. The precise origin remains controversial, with estimates spanning Central Asia, Iran, and the Levant; the most recent sources point to Iran and Anatolia, with Iran as the main centre. One vivid detail survives about how it began. Wild almond species were grown by early farmers, in the words of one account, "at first unintentionally in the garbage heaps, and later intentionally in their orchards." The reach of the tree kept growing. By the 12th century, Ibn al-'Awwam's Book on Agriculture included an article on almond cultivation in Spain, and today the domesticated form can be found as far north as Iceland.

• 4. The Bitter Gene

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  Some individual trees produce seeds that are markedly bitter, and behind that taste is a single recessive gene. That genetics is precisely why the almond was easy to tame. The sweet trait is recessive, so selecting the sweet type from the many bitter types in the wild marked the very beginning of domestication. The bitterness is not just unpleasant; it is dangerous. Bitter almonds contain the enzyme emulsin, which in the presence of water acts on two soluble glucosides, amygdalin and prunasin, to yield glucose, cyanide, and benzaldehyde, the chemical behind the bitter flavour. A single bitter almond may release four to nine milligrams of hydrogen cyanide, roughly 40 times the trace levels found in sweet almonds. The molecular switch is elegant. A point mutation in a bHLH transcription factor blocks the transcription of two cytochrome P450 genes, and that blockage produces the sweet kernel. The fruits from Prunus amygdalus var. amara are always bitter, as are the kernels of related species like apricot, peach, and cherry. The poison sets a hard limit on consumption. The acute oral lethal dose of cyanide for an adult is reported at 0.5 to 3.5 milligrams per kilogram of body weight, about 50 bitter almonds; for a child, five to ten may be fatal.

• 5. California's Pollination Machine

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  California produces about 80% of the world's almond supply, concentrated in the Central Valley where mild climate, rich soil, sunshine, and water once made for ideal conditions. The crop has a built-in vulnerability: the most widely planted varieties are self-incompatible, meaning each tree needs pollen from a genetically different tree to set seed. Orchards must therefore mix varieties, and insects must carry the pollen between them. At California's scale, native insects cannot do the job, which is why beekeepers are summoned each February. Much of the bee supply is handled by pollination brokers who contract with migratory beekeepers from at least 49 states. That business was hit hard by colony collapse disorder at the turn of the 21st century, which caused a nationwide shortage of honey bees and drove up the price of pollination. To shield growers from that cost, researchers at the Agricultural Research Service, part of the USDA, developed self-pollinating almond trees that combine independence with good flavour and yield. The numbers behind the U.S. industry are large. In 2017, California had a million acres and six almond varieties under cultivation, yielding 2.25 billion pounds of shelled almonds. In 2016, the value of total U.S. shelled almond exports reached $3.2 billion.

• 6. The Water Problem

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  A single almond requires roughly 1.1 US gallons of water to grow properly, and that figure sits at the centre of the crop's reckoning. Persistent droughts in California in the early 21st century made sustainable production harder, and the high water demand, large acreage, and need for pesticides have raised the prospect that California almond production may be unsustainable. Droughts have already pushed some producers out, lowering supply and raising prices. As water regulations change, some growers have torn out their almond orchards to plant younger trees or to switch to a thirstier crop's lower-water rival, pistachio. The industry has answered with sustainability efforts: water-efficient irrigation, funding for honeybee health research, and using waste biomass such as shells toward a zero-waste industry. Meanwhile the Southern Hemisphere has its own story. Australia is the largest almond region south of the equator, with orchards strung along the Murray River corridor in New South Wales, Victoria, and South Australia. In the 2024 to 2025 financial year, the national crop fell 5% but rose 20% in value to a record. Exports to China, 61% of the total, jumped nearly 130%, from 33,373 tonnes to 76,132 tonnes, while India ranked second at 19,803 tonnes.

• 7. Safety And Suspicion

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  After cases of salmonellosis were traced to almonds, the USDA approved a plan from the Almond Board of California to pasteurize almonds sold to the public. The rule, published in March 2007, became mandatory for California companies on the 1st of September 2007. Since then, raw, untreated California almonds have not been commercially available in the United States. Almonds labelled "raw" must be steam-pasteurized or treated with propylene oxide, known as PPO. The treatment drew controversy. The Almond Board states that PPO residue dissipates after treatment, while the Environmental Protection Agency has reported that propylene oxide has been detected in fumigated food products and that consuming contaminated food is a possible route of exposure. PPO is classified as Group 2B, possibly carcinogenic to humans. The rule was challenged in court by organic farmers organized through the Cornucopia Institute, a Wisconsin-based farm policy research group, which filed a lawsuit in September 2008. A federal judge dismissed it in early 2009 on procedural grounds, an appeals court ruled in August 2010 that the farmers could appeal, and in March 2013 the court vacated the suit, holding that objections should have been raised in 2007. Another invisible threat haunts the crop. Almonds are susceptible to aflatoxin-producing moulds such as Aspergillus flavus, potent carcinogens, which is why the European Union has required since 2007 that every almond shipment be tested for aflatoxin.

• 8. The Almond In Culture

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  In the Bible, the almond is mentioned ten times, beginning in Genesis 43:11, where it is described as "among the best of fruits." In Numbers 17, Levi is chosen from the other tribes of Israel by Aaron's rod, which brought forth almond flowers. The blossom even shaped the menorah of the Holy Temple, described in Exodus as cups "shaped like almond blossoms" set along its branches. In Jeremiah, the vision of an almond branch turns on a Hebrew wordplay between shaqed, almond, and shoqed, watching, a symbol of God's vigilance to fulfil His word. The fruit carries ritual weight beyond scripture. Many Sephardic Jews give five almonds to each guest before special occasions such as weddings. Christian symbolism uses almond branches for the virgin birth of Jesus, and almond-shaped haloes often encircle the Christ Child and Mary. The taste, too, reaches everywhere in the kitchen. Marzipan was developed in the Middle Ages, and since the 19th century almonds have gone into nougat, macaroons, biscotti, financiers, and almond milk, a soy-free dairy analog for the lactose intolerant and vegans. The reverence even has its own festival. On the 1st of February in Torrent, Spain, an event called La entrada de la flor sees members of a confraternity deliver a branch of the first-blooming almond tree to the Virgin.