50 Fun Facts About Salt

What is the chemical formula of common salt?

NaCl. Its two ingredients are a soft metal that fizzes violently in water and a poison gas used as a weapon in the First World War, yet bonded together they are safe to sprinkle on dinner.

What is the mineral name for natural crystalline salt?

Halite. The name comes from hals, the Greek for salt, and its crystals grow as cubes because the atoms inside stack in a cubic grid, which is why even table-salt grains are tiny boxes.

Sea-salt evaporation ponds often glow pink, red or green when seen from the air because of what?

Tiny algae and microbes. The colour tracks the saltiness: green algae rule the weaker ponds and red, salt-loving microbes the strongest, so the colour shows how far each pond has evaporated.

Solnitsata, a salt-making town often called Europe's oldest, lies in which modern country?

Bulgaria. Around 4500 BC its 350 or so people boiled spring brine into salt bricks to trade and ringed the town with stone walls; that wealth may explain the treasure-filled graves found nearby at Varna.

Roughly how much salt is produced worldwide each year?

300 million tonnes. Shared out, that is more than 30 kg a year for every person alive, far more than anyone could eat.

Most of the world's salt is never eaten, so what is its single biggest use?

Feedstock for chemical production. Split by electricity, brine yields chlorine and caustic soda, the starting points for PVC plastic and paper-making; de-icing roads is salt's other giant job.

The WHO's daily salt limit for adults, 5 grams, is about how much?

A teaspoon. In 2021 adults worldwide averaged more than twice that, about 11 grams a day, and the chief harm the WHO blames on the excess is raised blood pressure.

Which Austrian lakeside village has a salt mine billed as the world's oldest?

Hallstatt. Salt has been dug here for some 7,000 years and made the village so rich in the early Iron Age that a whole era of European prehistory, the Hallstatt culture, is named after its graves.

Which word for pay comes from the Latin for salt?

Salary. The Latin salarium clearly contains sal, salt, but nobody knows quite why: the popular story that Roman soldiers were paid in salt has no ancient evidence behind it.

Which everyday dish takes its name from the Latin for 'salted'?

Salad. The Romans dressed raw leaves with brine and called the dish herba salata, 'salted greens'; the same Latin root also gave us sauce, salsa, salami and sausage.

Which city fought Padua in the Salt War of 1304?

Venice. Padua had started building salt pans of its own on the edge of the lagoon; Venice saw a threat to its salt monopoly, won the brief war and had the monopoly confirmed.

Which English port flourished on exporting salt from Cheshire's mines?

Liverpool. Salt, coal and cloth went out from the Mersey and sugar and tobacco came back, an exchange that helped turn a small town into one of Britain's great ports.

Which ruler revived the gabelle, France's hated salt tax, in 1806?

Napoleon. The Revolution had scrapped it, but he needed money for his wars, and it then lingered into the 1940s; under the old kings, households had even been forced to buy a set amount of salt each year.

Which leader walked some 240 miles to the sea in 1930 to make salt in defiance of British law?

Mahatma Gandhi. He set out with a few dozen followers and hundreds more joined on the way; after he picked up a handful of salt at Dandi, some 60,000 Indians were jailed that year for following his lead.

In medieval West Africa, salt carried across the Sahara to Timbuktu was most often exchanged for what?

Gold. South of the desert salt was scarce and gold plentiful, so traders swapped one for the other; in parts of West Africa salt is said to have been worth its weight in gold.

The 1877 Salt War over salt lakes near Guadalupe Peak was fought around which Texas border city?

El Paso. Locals had always gathered the salt freely, so when a judge claimed the lakes for his family they rose in revolt, and a besieged company of Texas Rangers ended up surrendering to them.

Which general supposedly sowed Carthage with salt in 146 BC, a story now regarded as apocryphal?

Scipio Aemilianus. He did raze Carthage in 146 BC and sell the survivors into slavery, but no ancient writer mentions salt; the tale was attached to Carthage many centuries later.

Which desert people have traditionally run the Azalai salt caravans across the Sahara?

The Tuareg. Their camel trains hauled slabs of salt from the mines of Taoudenni south to Timbuktu, though most of the salt now makes the journey by truck.

In which African land were slabs of rock salt used as coins?

Abyssinia. The blocks, called amole, were cut from the salt plains of the Danakil Depression and passed as money across the Ethiopian highlands; their use is recorded as late as 1911.

Which fish, salted and dried, is the basis of Portugal's national dish, bacalhau?

Cod. The fish comes from far-off northern waters such as Newfoundland's Grand Banks, and salting was what let it survive the voyage; Portugal is said to have over a thousand recipes for it.

A pinch of table salt thrown into a gas flame makes it burn which colour?

Yellow. The colour comes from the sodium in the salt, and it is the very same light, at one sharp wavelength, that gives sodium street lamps their orange-yellow glow.

Salt keeps winter roads clear by lowering which property of water?

Freezing point. The trick has a floor, though: even the strongest brine turns solid at around −20 °C, so in deeper cold road crews switch to other salts such as calcium chloride.

Iodine is added to table salt mainly to prevent which condition?

Goitre. A thyroid starved of iodine swells into a lump in the neck; the deeper cost is to the brain, because iodine deficiency is the world's leading preventable cause of intellectual disability.

Kosher salt takes its name from the Jewish practice of using coarse salt to do what to meat?

Draw out the blood. Jewish law forbids eating blood, so meat is salted and left to drain; the salt itself is no more kosher than any other, its big flakes are simply the right size for the job.

Low-sodium table salts swap part of the sodium for which other element?

Potassium. Its chloride tastes salty too, so blends of the two pass for ordinary salt, and WHO guidance suggests households replace regular table salt with them.

In France and Germany, fluoride is added to table salt to protect what?

Teeth. Fluoride hardens tooth enamel against decay; countries that do not fluoridate their tap water, France and Germany among them, sell fluoridated table salt as the alternative.

Which sea salt is skimmed from the surface of evaporating brine in salt pans?

Fleur de sel. The 'flower of salt' is a fragile crust of crystals that floats on the brine and has to be raked off gently by hand; the ordinary sea salt is what sinks to the bottom.

Which organs keep the salt level of your blood in balance by filtering out the excess?

Kidneys. They filter about half a cup of blood every minute; eat more salt than they can clear and the body holds on to extra water to dilute it, which is what pushes blood pressure up.

Where does most of the sodium Americans eat come from?

Packaged and restaurant food. It supplies over 70% of the sodium Americans eat, and sandwiches, pizza and soup rank among the biggest contributors, not just obviously salty snacks.

Which country was the world's largest salt producer in 2018?

China. It has long practice: centuries ago drillers in Sichuan bored wells up to half a mile deep to reach brine, then burned the natural gas that came up with it to boil the brine into salt.

What is the approximate salinity of seawater?

3.5%. The salt comes mostly from the land: rain slowly dissolves it out of rocks and rivers carry it to the sea, where it has built up over ages while the water itself evaporates and falls again as rain.

The vast Goderich salt mine runs out beneath Lake Huron from which Canadian province?

Ontario. Its owner bills it as the largest underground salt mine in the world, as deep as Toronto's CN Tower is tall; the salt was struck by accident in 1866 by a man prospecting for oil.

Pink 'Himalayan' salt is mined mainly in which country?

Pakistan. It comes from the Khewra mine in Punjab's Salt Range, hills well south of the Himalayas; legend says the deposit was found when Alexander the Great's horses began licking the rocks.

Poland's Wieliczka salt mine, a UNESCO site, lies just outside which city?

Kraków. Its miners left four chapels and dozens of statues carved out of the rock salt itself; table salt was made here for over 700 years until 1996, when falling prices and flooding ended it.

In which country can visitors enter a cathedral carved 200 metres underground inside the Zipaquirá salt mine?

Colombia. It grew from a small shrine that miners carved to pray for protection before their shifts; the first cathedral opened in 1954 but was closed as unsafe, so a new one was dug to replace it.

In which country is the Salar de Uyuni, the world's largest salt flat?

Bolivia. Beneath its crust lies brine holding one of the world's largest reserves of lithium, the metal in phone and car batteries, and after rain a film of still water turns the whole flat into a vast mirror.

What is the vast, flat Salar de Uyuni used to calibrate?

Satellite altimeters. Over more than 10,000 square kilometres the surface varies in height by less than a metre, so satellites such as NASA's ICESat have checked their height readings against a GPS survey of it.

Which sea is nearly ten times saltier than the ocean?

Dead Sea. The name is earned: fish swept in from the River Jordan soon die, while the dense water holds bathers up like corks.

Which Bible figure was turned into a pillar of salt?

Lot's wife. She looked back at burning Sodom against the angels' warning; the Bible never names her, but a tall pillar of rock salt on Israel's Mount Sodom is traditionally pointed out as her.

In which Japanese sport do competitors toss salt to purify the fighting area?

Sumo. The ring counts as sacred ground under Shinto tradition, which uses salt to purify people and places; shops and restaurants in Japan set small piles of it by the door for the same reason.

Huixtocihuatl was the goddess of salt and salt water in which civilisation's religion?

Aztec. In the telling a Spanish friar recorded, she mocked her brothers, the rain gods, who banished her to the salt beds, and it was there that she discovered how salt is made.

A kipper is the salted, smoked form of which fish?

Herring. The fish is split open like a butterfly from tail to head, salted and then cold-smoked over smouldering oak; before refrigerators, salting like this was one of the main ways to keep food.

In 1901 a well drilled into the Spindletop salt dome in Texas struck a huge fountain of what?

Crude oil. It spouted for nine days before the crew could cap it, and the boom it set off gave rise to oil giants such as Texaco and Gulf Oil.

Which Galápagos reptiles get rid of the salt they swallow at sea by sneezing it out of their noses?

Marine iguanas. Glands by the nostrils filter the salt from their blood, and the spray dries into a white crust on their heads; sea turtles shed theirs instead as salty 'tears'.

What is the name of the Austrian city Salzburg usually said to mean?

Salt castle. That is the usual reading of Salz and Burg, and the salt was real enough: it was mined in the hills nearby and shipped down the river past the city.

Which ruler in the Book of Judges razed the rebel city of Shechem and sowed it with salt?

Abimelech. Made king at Shechem after murdering his brothers, he destroyed the city when it turned on him, and died soon after when a woman dropped a millstone on his head from a tower.

In Leonardo's Last Supper, which apostle has knocked over the salt cellar?

Judas. The scene is often given as the reason spilling salt is unlucky, but the omen is far older than the painting, and Leonardo was probably playing on a belief his viewers already held.

Which classic cocktail is traditionally served in a glass with a salted rim?

Margarita. The salt is doing a job: it dulls bitter tastes and so lets sweet ones come through, the same trick a pinch of salt plays in cooking.

The Bonneville Salt Flats in Utah are best known as a venue for what?

Land speed records. The crust is flat and hard for miles and drew record-chasers such as Sir Malcolm Campbell in the 1930s, though the salt has since thinned so much that race meetings have had to be cancelled.

Which phrase for thoroughly decent, dependable people comes from Jesus's Sermon on the Mount?

Salt of the earth. Jesus tells his followers 'You are the salt of the earth', then warns that salt which has lost its taste is good for nothing but to be thrown out and trampled.