Why salt was so important throughout history

July 29, 2018

These days, salt is so abundant that it’s easy to take it for granted. If you had lived in any other time in history, though, chances are that your relationship with salt would have been dramatically different.

Here are some of the big themes from Salt: A World History by Mark Kurlansky around why salt was so important throughout history.

Salt keeps your body functioning

Chemically speaking, a salt is any substance that’s produced by the reaction of an acid with a base. The salt that we humans are particularly fond of is called sodium chloride. Sodium is crucial for the basic functioning of your body, including moving nutrients and oxygen, sending nerve signals, and moving muscles. Chloride helps you digest and breathe. A healthy body has about 250 grams of salt in it, which is about 3/4 of a dry cup. Your normal bodily processes naturally deplete your salt reserves, which is why you need to constantly replenish them.

Salt preserves food

It’d be nice if we could just leave meat, vegetables, and other foods out in the open, and eat them whenever we get hungry. But unfortunately, that’s not how our universe works. When you leave food out, billions upon billions of microscopic creatures start feasting on it and breaking it down into simpler organic matter. Unfortunately for us, this process usually converts our precious food into stuff that is toxic to our bodies.

Many societies literally stumbled upon the preserving powers of salt. The story usually goes like this: some hunter wounded an animal, lost it in the forest, then discovered it a few weeks later in a salt spring, looking pretty much the same as when it was alive. Apparently, the natural response for our ancestors upon discovering a scene like this was: “I wonder if it tastes good?”

To preserve meat in salt, you basically just pile on the salt so that the meat is completely covered in it. Most organisms can’t survive in a highly salty environment. The salt essentially sucks out the liquid from their bodies through the process of osmosis. In other words, a layer of salt around meat acts as a microscopic no man’s land.

Salt preserves vegetables through a slightly different process, called fermentation. Fermentation is basically controlled rotting. If you leave a vegetable on the counter, the bacteria in the air break it down into stuff that makes us sick, as mentioned before. But, if you stick a vegetable in salt water, a different class of bacteria breaks it down into stuff that we can eat. The “bad” bacteria that live in the air can’t grow in the salt water, whereas the “good” can.

P.S. supposedly modern science is discovering that, not only can we eat fermented foods, but that they may actually be good for us. The fermented veggies are full of nutrients, and the “good” bacteria help us with digestion. Check out the The Easy Fermenter if you’d like to give it a try. Homemade sauerkraut is a good and easy first recipe, and tastes completely different than the store-bought stuff. To make sauerkraut you literally smash the salt into the cabbage with your hands until there’s a pool of cabbage juice, jam the smashed cabbage and brine into a jar, then just wait a few weeks.

Salt encouraged global trade

The ability to preserve food gave fishers the ability to travel farther and farther. Previously, they were limited to the waters near markets because you only have so much time before a fresh catch begins to rot. Salt enabled them to travel deep out into the sea, where fish were more abundant. Some fishing industries sprang up because they worked so well with salt. For example, cod became a huge market throughout Europe, because cod are low in fat, which makes them preserve well in salt.

Without salt, traveling at sea for months at a time would have been incredibly risky. You’d have to depend on the ocean to give you a steady supply of fish every few days, which was unlikely. Salt enabled you to bring a lot of food onboard, which would last for weeks or months. Every now and then, you might encounter a patch of fish at sea, which could further supplement your rations. If our ancestors hadn’t devised a reliable means for preserving food, the Age of Exploration would never have happened.

Salt financed governments

Given how important salt is to our bodies, and its crucial role in preserving food, it naturally became a very important resource in ancient societies. Ancient governments fretted over control of salt like modern ones squabble over oil. As an emperor, if you controlled the salt, you controlled the population. Since everyone needed it to survive, any fee on salt essentially became a head tax, which is a uniform tax imposed on everyone. Taxes like these were controversial, though, because the wealthiest citizens paid the same price as the poorest ones.

Conversely, if you couldn’t control the salt, you had a harder time controlling the population. Some historians argue that France’s abundance of salt partly explains why it was so difficult to govern throughout history. While traveling through South America, Hernán Cortés remarked on his admiration for the Tlatoque people, who “ate no salt because there was none in their land,” making it easier for them to keep their independence.

Salt was a major cause of rebellion

Mild shock: humans don’t like it when their governments try to restrict access to resources that they need to survive. Many famous rebellions and revolts were partly caused by citizens reacting against governments that were too stingy with the salt. Early American settlers had vast amounts of fish that they could potentially export, but not enough salt to preserve them with, because the British imposed salt quotas on them. In the century leading up to the French Revolution, the burden of salt taxes fell disproportionately on Parisians, who would later become the major drivers of the revolution. In 1680 the Paris region was one-third of the total population, used one-quarter of the total salt, yet paid two-thirds of total salt taxes.

The protest that sparked India’s collective revolt against British rule was Gandhi’s Salt March, in which he walked 240 miles to the ocean to pick up some salt. Britain’s rule in India was so heavy-handed, that they literally made it illegal for Indians to pick up salt. British salt producers had lobbied the British government to shut down all Indian salt production, forcing Indians to buy expensive British salt. The British also constructed a 12-foot wide, 14-foot tall thorn hedge separating the salt-producing region of India from the rest of the country. At its peak, 12,000 people were employed by the colonial government to maintain the 2500-mile-long “Great Hedge of India.”Gandhi wisely focused his initial protests on salt, because he knew it was an issue that affected all Indians equally.

Salt was strategically important for warfare

Aside from the fact that salt is an input for making gunpowder, it was also a strategic resource for war efforts. Without salt, you couldn’t preserve food for your soldiers. Any warring group without easy access to salt was at a major strategic disadvantage. This is exactly what happened to the Confederacy during the American Civil War. Early on in the war, Lincoln imposed a blockade on all Southern ports, which crippled their salt supply, because they imported most of their salt. As the war dragged on, famine became a serious issue throughout the South and made it very difficult to sustain morale. The salt shortage in the South was so severe that one Confederate soldier concocted this recipe for preserving meat without salt:


Eat it early in the Spring.

— Confederate States Almanac, Macon, Georgia, 1865

Salt is still important today…

Just for different reasons. USA is a major consumer of salt. Its salty food is just a fraction of its total consumption. The main use is de-icing roads, which makes up 51% of US consumption. When hunting for oil fields, geologists keep an eye out for salt domes. Solid salt rock is usually impenetrable, so any organic matter next to it gets trapped and has nowhere to go, which eventually creates oil. Salt mines are used to store the US’s emergency oil reserves in Louisiana and Texas, and also nuclear waste elsewhere. Officials have discovered that the salt mines storing the oil reserves aren’t as tightly sealed as previously thought, and oil is leaking, which doesn’t bode well for the nuclear waste sites…