50 Fun Facts About Salt

What is the chemical formula of common salt?

Sodium chloride is the source of two essential dietary minerals, sodium and chlorine.

What is the mineral name for natural crystalline salt?

Its crystals are translucent cubes; impurities can tint them blue or purple.

Around when does some of the earliest evidence of salt processing, in present-day Romania, date from?

Neolithic people at Poiana Slatinei boiled spring water; a saltworks at Xiechi Lake in China is about as old.

Which Bulgarian salt-mining settlement is thought to be Europe's first city?

It supplied the Balkans with salt from about 5400 BC.

Roughly how much salt is produced worldwide each year?

Only a small share is eaten; most goes to make chemicals such as caustic soda and chlorine.

What is the single greatest use of salt?

It yields caustic soda and chlorine for PVC, plastics and paper pulp; food is only 17.5% of world use.

How much salt per day does the WHO say adults should stay under?

That equals 2,000 mg of sodium; typical Western intake is about 10 g of salt a day.

Which Austrian town was the site of the world's first salt mine?

The Hallstatt culture began mining there around 800 BC; Salzburg means 'salt castle' and Salzach 'salt river'.

From which Latin root does 'salary' derive?

The popular claim that Roman legionaries were paid in salt is baseless; nobody knows the true reason.

What does the word 'salad' literally mean?

It comes from the ancient Roman habit of salting leaf vegetables.

Which city fought Padua in the Salt War of 1304?

Venice fought the War of Ferrara in 1482-84 for the same reason: control of the salt supply.

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

Cities on overland salt routes likewise grew rich by levying duties.

When was France's salt tax, reimposed by Napoleon, finally abolished?

The hated gabelle was one of the causes of the French Revolution.

How long was Gandhi's 1930 Salt March from Sabarmati Ashram to Dandi?

The 24-day walk began with 78 volunteers and ended with Gandhi illegally making salt from seawater on 6 April.

How many days did the Salt March last?

It ran from 12 March to 6 April 1930; over 60,000 Indians were jailed in the wider salt satyagraha.

Which nineteenth-century Texas conflict was triggered by access to salt flats?

The San Elizario Salt War of the late 1860s and 1870s was fought over access to salt flats.

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

The Bible has King Abimelech salting Shechem; the Carthage tale seems to be a later invention.

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

Camels still cross from southern Niger to Bilma, returning laden with salt pillars and dates.

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

South of the Sahara, salt itself served as currency; Gabon's coast peoples traded sea salt inland.

What did the Egyptians export to the Phoenicians from about 2800 BC in exchange for cedar and Tyrian purple?

Salt and salted birds were also placed in Egyptian tombs of the third millennium BC.

How much salt dissolves in a litre of water?

In solution the compound splits into Na+ and Cl- ions.

To what temperature can salt lower water's freezing point at 23.31% concentration?

That is why salt de-ices roads; a saturated brine boils at about 108.7 °C.

What is added to iodised salt to prevent iodine deficiency?

Iodised salt has been used since 1924; iodine deficiency affects some two billion people.

Since what year has iodised salt been used to correct iodine deficiency?

Deficiency causes goitre and is the leading preventable cause of intellectual disability.

Which additive gives fortified table salt a yellow colour?

Vitamin B9 helps prevent neural tube defects; 'doubly fortified' salt carries iodide and iron.

What share of table salt sold in France contains added fluoride?

Fluoridated salt is used where water is not fluoridated, to fight tooth decay.

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

Korean bamboo salt is roasted in bamboo plugged with mud; kosher salt is prized for brining.

Roughly what percentage of table salt is sodium by weight?

So a 6 g teaspoon carries about 2,400 mg of sodium.

In the US, what share of dietary sodium comes from processed and restaurant foods?

Only 11% comes from cooking and table use; the rest is naturally present in food.

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

China made 68 million tonnes, the US 42 million and India 29 million.

What is the approximate salinity of seawater?

About 35 g of dissolved salts per kilogram of water; the oceans are effectively an inexhaustible source.

Where is the Sifto mine, the world's largest underground mine?

It lies mostly 550 m below Lake Huron and yields about seven million tons of salt a year.

How many storeys does Pakistan's Khewra Salt Mine have?

Eleven are underground, with 400 km of passages; Himalayan salt extraction there should last another 350 years.

When did Poland's Wieliczka Salt Mine stop producing table salt?

Excavated from the 13th century, it is a UNESCO site with chapels and statues carved from rock salt.

How deep does the Wieliczka mine reach?

Its passages and chambers run for over 287 km, and its rock salt is grey rather than white.

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

Its 8 m salt crust covers lithium-rich brine and, after rain, becomes the world's largest mirror.

What is the Salar de Uyuni used to calibrate?

Its huge, extremely flat surface varies in elevation by less than a metre.

How does the Dead Sea's salinity compare with the ocean's?

Its 34.2% salinity gives it a density of 1.24 kg per litre, which is why swimmers float.

Which Bible figure was turned into a pillar of salt?

She looked back at Sodom and Gomorrah; Jesus later called his followers 'the salt of the earth'.

In Shinto, what is salt used for?

Small piles of salt sit by entrances to ward off evil and attract customers.

Which Aztec fertility goddess presided over salt and salt water?

Chalchiuhtlicue was the goddess of rivers and fresh water.

How much sodium does kipper contain per 100 g compared with 67 mg in fresh herring?

Bacon carries 1,480 mg against 63 mg in pork; salting was the main preservation method before refrigeration.

For which metal is salt used as a flux during production?

A layer of molten salt floats on the metal and draws off iron and other contaminants.

Which taste-bud protein has been shown to act as the human salt receptor?

Saltiness is one of the five basic tastes, and salt suppresses bitterness in other foods.

What does the name of the Austrian city Salzburg literally mean?

It sits on the Salzach, the 'salt river', within 17 km of Hallstatt and Hallein, all named from the German word Salz.

Which biblical king was ordered by God to sow the city of Shechem with salt?

Salting the earth was a symbolic act of destruction; the later claim that Rome did it to Carthage is considered apocryphal.

Besides the 1304 Salt War, Venice fought which 1482-84 conflict over control of the salt trade?

Salt also played a role in the American Revolution and the San Elizario Salt War in Texas.

What was the first anticaking agent added to salt, in 1911, to make it flow freely?

Sodium ferrocyanide, or yellow prussiate of soda, is another agent used today to stop salt clumping.

Under which of the Great Lakes does the Sifto mine, the world's largest underground mine, mostly lie?

Workings sit about 550 metres below the lake bed near Goderich, Ontario, yielding about seven million tons of salt a year.

In which religion do devotees sprinkle salt on cremated remains before the ashes are buried?

Jains also lay an offering of raw rice with a pinch of salt before a deity as a sign of devotion.