49 Fun Facts About Nuts

Botanically, the peanut belongs to which plant family?

Legumes: the peanut is a cousin of peas and beans, and like them it hosts root bacteria that pull nitrogen from the air, leaving the field richer for whatever is planted next.

Peanut pods develop underground, a rare trait known by what name?

Geocarpy: after pollination a stalk called a peg pushes the young pod a few inches into the soil to ripen, which is why Linnaeus named the species hypogaea, 'under the earth'.

Which US president ran his family's peanut farm before entering politics?

Jimmy Carter: when his father died in 1953 he resigned from the Navy's nuclear submarine programme to save the family business, and he handed it to trustees before he was sworn in as president.

Which scientist promoted hundreds of peanut-based products in the American South?

George Washington Carver: his cotton-and-peanut rotations revived worn-out soil but left farmers with barns of unsold peanuts, so he set about devising some 300 uses for them.

The oldest known peanut pods, well over 7,000 years old, came from an Andean valley in which country?

Peru: the pods lay among ancient garden plots, hoes and irrigation canals in a dry valley, evidence that people in the Andes were farming far earlier than the sparse record had suggested.

Peanuts stored warm and damp can grow a mold that produces which cancer-causing toxin?

Aflatoxin: it is made by the mold Aspergillus flavus, which can take hold in the field or in storage, so every truckload of raw American peanuts is tested before it can be sold.

Which US state is by far the world's biggest almond-growing region?

California: its growers say they supply about 80% of the world's almonds, shipped to more than 90 countries, though the tree was first tamed in the Bronze Age Middle East.

The almond tree is a close relative of which fruit, sharing the subgenus Amygdalus?

The peach: on the tree an almond looks like a small, leathery green peach, but where we eat a peach's flesh and throw away the stone, with an almond we do the opposite.

Bitter almonds are dangerous because they can release which toxin when eaten?

Hydrogen cyanide: chewing a bitter almond frees it from a compound called amygdalin, and a single mutation that switched that compound off is what made sweet almonds safe to farm.

Which paste of ground almonds and sugar is rolled out to cover cakes and moulded into sweets?

Marzipan: on a British Christmas cake it is the yellow layer hidden under the icing, there to give a smooth, flat base, while Sicilians paint theirs to pass for real fruit.

Each February, which insects are trucked into America's almond orchards from across the country?

Honeybees: almond blossom needs more cross-pollination than wind and wild insects can supply, so beekeepers haul in more than a million hives on thousands of trucks.

The cashew nut hangs below a swollen, pear-shaped accessory fruit called the cashew what?

Apple: the cashew apple is really the swollen stalk behind the nut, juicy enough to press for drinks, and in parts of Latin America people long prized it and threw the nut away.

Cashew shells contain an irritant chemically related to the toxin in which plant?

Poison ivy: the two plants are botanical cousins, and in 1982 dozens of Americans came out in a poison-ivy-like rash after eating imported cashews with bits of shell left in the bag.

Explorers from which country carried the cashew from South America to India in the 1500s?

Portugal: its traders planted the tree along the coasts of India and Mozambique in the 1500s simply to hold the soil against erosion, and it ran wild before anyone valued the nut.

Which West African country, the world's biggest cocoa grower, also led the 2023 cashew harvest?

Ivory Coast: the cashew tree is native to north-east Brazil, yet the biggest harvest now comes from the far side of the Atlantic, with India next in line.

Pistachio orchards must mix which trees?

Male and female: only the female trees bear nuts, so growers plant just enough males among them, roughly one to every ten, to keep the orchard supplied with pollen.

What does a ripe pistachio's shell do that growers deliberately bred for?

It splits open with a pop: botanists call the split dehiscence, and it matters at market, because nuts whose shells stay shut are worth far less than ones that open themselves.

The word pistachio reached English by way of Greek and Latin from which language?

Persian: English borrowed the word twice, first from French as 'pistace' in the late Middle Ages and later, in the form used today, from Italian.

Bulk pistachios are treated as a risky cargo at sea because they can do what?

Catch fire by themselves: the oil in a damp, tightly packed load breaks down and gives off heat, so a cargo can smoulder into flame, which is why shippers insist on dry, well-aired holds.

The Old English name behind the word walnut literally described it as what kind of nut?

A foreign nut: the tree reached the Germanic peoples from Gaul and Italy, so they gave it a name that told it apart from the hazelnuts growing wild at home.

Which vegetable-garden favourite is notorious for wilting when planted near a black walnut tree?

Tomatoes: walnut roots, leaves and husks give off juglone, a chemical that starves sensitive plants of energy and water, and it lingers in the soil for years after the tree is felled.

Which country produced about 35% of the world's walnuts in 2023?

China: its 2023 harvest was the world's largest, yet in North America the common walnut goes by the name English walnut.

Macadamia trees are native to which country?

Australia: Aboriginal people gathered the nuts from subtropical rainforest long before any orchard existed, yet the macadamia became a worldwide crop only within the last century.

Where were macadamias first grown as a commercial crop on a large scale?

Hawaii: seeds planted there in the 1880s grew into the first big orchards, and DNA tests suggest nearly all of the islands' trees descend from one small wild stand, perhaps a single tree.

Macadamia nuts are named after John Macadam, a 19th-century man of which profession?

Chemist: Glasgow-born John Macadam had just become secretary of his adopted city's leading scientific society when the botanist Ferdinand von Mueller named the tree in his honour.

Macadamia nuts are notoriously toxic to which household pet?

Dogs: a handful can leave one weak in the hind legs, trembling and listless within hours, and vets still don't know which compound in the nut is to blame.

Brazil nuts are famous for an unusually high amount of which mineral?

Selenium: how much depends on the soil the tree stood in, so a single nut can supply anything from a tenth of an adult's daily need to nearly three times it.

Brazil nut trees soak up traces of which element, one of Marie Curie's discoveries?

Radium: the tree draws it from the soil along with barium, its chemical look-alike, so Brazil nuts carry far more of it than most foods do.

Which large rodent gnaws open Brazil nut capsules and buries seeds that later sprout?

The agouti: it is said to be the only rodent able to gnaw through the woody casing, and the nuts it buries for later and never digs up are how new trees get planted.

As of 2024, which landlocked country matches Brazil as a leading source of Brazil nuts?

Bolivia: its Amazon forests yield almost as many nuts as Brazil's, and because the trees crop poorly in plantations, nearly every one is gathered from the wild.

Brazil nuts grow packed inside a woody pod, fitted together like the parts of which fruit?

An orange: the wedge-shaped nuts sit like segments inside a woody ball that can weigh about 2 kilograms, heavy enough to injure anyone standing underneath when it drops from the canopy.

Which country grew more than half of the world's hazelnuts in 2023?

Turkey: its Black Sea hills out-produce the rest of the world put together, and the nut's other English name, filbert, honours St Philibert, whose late-August feast day falls as the crop ripens.

Evidence of hazelnut roasting more than 8,000 years old was found on an island in which country?

Scotland: a pit on the Hebridean island of Colonsay was packed with charred shells, and as the island probably had no deer to hunt, its Stone Age visitors seem to have come for the hazel harvest.

Pecan is the official state tree of which US state?

Texas: lawmakers named the pecan the state tree in 1919, voted to confirm it eight years later, and have since made it the official health nut and pecan pie the official state pie.

The word pecan comes from which group of Native American languages?

Algonquian: the word reached English through French settlers, who had borrowed it from the Illinois people's pakani, a word that meant simply 'nut'.

What nearly wiped out the roughly four billion American chestnut trees in the early 1900s?

A fungal blight: first noticed at New York's Bronx Zoo in 1904, it left the species functionally extinct, because the old roots still send up shoots but the fungus kills each one before it matures.

Chestnut flour makes a poor loaf of bread on its own because of which drawback?

It will not rise: chestnut flour has no gluten to trap the gas that lifts a loaf, the very quality that now earns it a place in gluten-free baking.

Which Christmas standard opens with the image of chestnuts roasting on an open fire?

The Christmas Song: Bob Wells jotted down its wintry opening lines on a sweltering summer day, simply to think himself cool, and Mel Tormé helped him finish the lyric in about 45 minutes.

Pine nuts are not true nuts because pines belong to which group of plants?

Gymnosperms: the name means 'naked seeds', because a pine's seeds sit bare on the scales of its cones instead of being sealed inside a fruit, as a true nut is.

Pine nuts are a classic ingredient of which Italian pasta sauce?

Pesto: the name comes from the Genoese word for 'pounded', because the pine nuts, basil, garlic and cheese were traditionally crushed together in a marble mortar.

Acorns are the nuts of which group of trees?

Oaks: every few years they drop a bumper crop all at once, and in the north-eastern United States the mice that feast on it multiply, followed a year or two later by more ticks carrying Lyme disease.

Which bitter compounds in acorns can cause kidney failure in cattle that eat too many?

Tannins: cattle cannot cope with them and can die of kidney failure, whereas people who eat acorns first crush them and wash the bitterness out with water.

Pigs turned loose each autumn to fatten on fallen acorns give which prized ham its flavour?

Ibérico ham: the top grade is labelled 'de bellota', Spanish for acorn, because the pigs spend their last months roaming wooded pasture and eating little but acorns and grass.

Portuguese and Spanish sailors named the coconut 'coco' after what they saw in the three dents on its shell?

A face: coco was their word for a grinning face or bogeyman, or in some tellings a head or skull, and the three 'eyes' at the base of the shell reminded them of one.

Genetic studies place the coconut's centre of origin in which region?

Austronesian sailors carried it as far west as Madagascar and as far east as the Pacific Islands, using it for food, water and boat materials.

Dried coconut flesh, pressed for its oil, is known by what name?

Copra: once the oil has been pressed out for cooking, soap and cosmetics, the leftover cake is fed to horses and cattle, so almost none of the dried kernel is wasted.

Nutella is produced by which Italian company?

Ferrero: in the lean months after the Second World War, founder Pietro Ferrero stretched a little cocoa with plenty of local hazelnuts to make an affordable treat, the paste that grew into Nutella.

A proposed 2012 French tax nicknamed the Nutella tax targeted which ingredient?

Palm oil: it makes up about a fifth of every jar, so a French senator's plan to quadruple the tax on it was named after the spread, and promptly drew a protest from Malaysia's growers.

The butter pressed from which African tree nuts goes into skin creams and stands in for cocoa butter in chocolate?

Shea nuts: known abroad mostly from moisturisers, their ivory-coloured butter is an everyday cooking fat in parts of West Africa, where the trees grow wild across the savannah.