Salt, we need it to add flavour to our food and to maintain proper pH in the blood but how much do you know about it? Let's take an in-depth walk through the history, types, uses, and functions of salt. Salt is biologically important but it is also culturally important. The oldest human settlements can be directly traced to the availability of salt. Not only because we need it for biological functions but also because it is essential to food preservation. Without salt, it was impossible to preserve meats, ferment vegetables, or maintain electrolyte balance within the body.
The oldest salt mine still in use is located in Austria, this mine, named Hallstatt, was and is so important that its name was used for an epoch and culture. This mine has been in continuous use for 7000 years. Significant archaeological finds could be made in this area because the salt preserved them when they otherwise would have rotted long ago. In China there is a 4,700 year old text that explains two methods of harvesting salt that are very similar to methods still used today, it also mentions over 40 different types of salt!
There are a few places in the world that have inland saltwater springs, Britain happens to have a few. Around these sites, they have managed to make a few discoveries on how they got the salt from the water. The water would be placed into large shallow pans and allow the brine to become concentrated. From there the brine would be placed in smaller vessels to finish evaporation, the clay vessel could then be broken to reveal the salt lump inside. In the future the pans would change from clay to metal and fires would be lit under them to speed up evaporation and allow the second clay vessel to be skipped. In Roman times the soldiers were paid in part with salt, the Latin word for salt (salis) is where we get the word salary and soldier among many other words. Salt was so important is was considered to be worth its weight in gold.
It is believed that salt was one of the first traded commodities due to its essential nature. If a village was not near a source of salt then someone would have to bring it to them, and it won't be free. Methods for producing sea salt would go unchanged for well over a thousand years until the Scottish switched from the lead pans the Romans introduced to iron pans. A couple of centuries later English salt works would soon be forced to also switch to iron due to the need to use coal for the fires. Coal burns much hotter which means the lead pans melted often. The reason the English salt makers did not wish to switch from lead to iron was mostly that salt produced in iron pans was much coarser than salt produced in lead pans, not to mention the cost of the initial investment. Additionally lead was not corroded by the brine and when a pan couldn't be used anymore it was easy to melt back down to form a new pan. Riveted iron pans would rust when the brine came into contact and if not maintained constantly the rust could discolour the salt. Inland salt works in England were known as "wich"s, they were thus titled long before the Romans invaded. If you visit any location with "wich" in the name it should indicate that salt works were present at some point in the town's history, some example names would be Northwich and Nantwich.
In 1930 India was still under British rule. During that time Britain introduced taxation and other regulations on traditional salt makers in India and would use force to stop salt production to try and force them to pay the taxes. As a response, Gandhi started a walk to a specific village in question, Dandi. This march started at his home and he was initially joined by 78 other people, but would gain thousands more during the 24-day march. When Gandhi got to the village he immediately made salt, which the British had deemed illegal unless the taxes were paid. He didn't stop at Dandi though, he continued down the coast and made salt at each saltworks. Eventually, Gandhi would be arrested but that didn't stop the action he started. Later he was released and during that time international attitudes had changed because of the simple act of making salt. This "salt march" was a direct but peaceful act of rebellion against British rulership and would ultimately gain India it's independence back. We could spend all day just following the history surrounding salt around the globe.
At this point, however, we will switch focus but if you would like to know more about global history and salt simply go to the bottom of this article to see additional resources.
How salt is harvested comes in a few primary methods. The first is mining, necessity is the creator of innovation, through mining salt these people developed our first mining techniques that would later be applied to metals and other resources acquired through mining. The second is for sea salt. Across the globe, the methods used are very similar and developed this way independently of each other. Seawater is sent through successive shallow clay pools while being carefully looked after at every stage. At the last set of pools, the salt crystals will be raked regularly with a special wooden rake to prevent a crust from forming. A crust would stop the water from evaporating and thus we would still have saltwater instead of salt. It will then be moved from the pool and piled into large cones of several tonnes each until ready for sale.
Salt deserts like those found in Bolivia and Utah need to be harvested a little differently. Some places use specially designed machines that are very impressive. Places that still harvest these deserts by hand-cut into the ground and lift up slabs of salt which will be transported to the market where they can be sold.
Regular table salt is typically brought to the surface using a process called Solution Mining. Solution mining is when they drill down into the salt deposit and force fresh water into the salt and then pump it back to the surface to go through an evaporation process. The evaporation process has a couple of stages; first, they boil it in a special chamber that allows steam to escape as the sodium chloride collects at the bottom. The second stage is where they add anti-caking agents and this allows the last of the moisture to be removed. The first stage of evaporation is where the other trace minerals end up removed.
Unfortunately more and more salt productions are being moved away from the artisanal (hand made) and into fully industrial methods. When the salt will be used for industrial processes this makes absolute sense. Some industrially made products that require salt before they can be made include bleach, caustic soda, and chlorine.
How is salt part of the manufacture? A salt brine is run through a special membrane that will separate the brine into sodium, chloride, and hydrogen. These basic substances are then used to create different products. Chlorine is used for more than just swimming pools, just take a look at your kitchen faucet. Ultimately that translates to salt gives us safe drinking water. But chlorine is used in thousands of other products as well.
There are 26 different types of edible salt. Yup, you read 26. Wikipedia can give you the full list but for now, we will just go over a few of the more easily acquired ones. These can all be used for culinary purposes.
Pink Himalayan;
Colour is pink as implied by the name.
Mined from salt deposits in India and Pakistan.
84 trace minerals, presence of iodine may depend on which specific mine it came from.
Mild and well-rounded flavour.
Sel Gris (Celtic sea salt);
Colour is gray.
Hand-harvested from the Celtic sea off the coast of France.
82-84 trace minerals.
Flavour is moderate and mellows further with cooking.
Hawaiian black sea salt;
Colour is black.
Hand-harvested sea salt with purified coconut shell charcoal.
82-84 trace minerals.
Robust flavour with an earthy tone.
Kala namak;
Colour is deep red to purple when coarse, light pink when ground.
84 trace minerals if pink Himalayan is used for the base.
Flavour is sour and pungent due to high sulphur content, tastes similar to cooked egg yolk.
Kala namak is a little different from the previous salts mentioned because they take a basic salt such as pink Himalayan and then heat it up and infuse multiple spices into it. Some brands use basic sodium chloride to make their product so check carefully to get the best benefits.
You'll notice that none of these salts are white. Commercially available white salt has often been processed in a way that strips it of trace minerals, making it actually just sodium chloride rather than true salt. Anti-caking agents may also get added to make the salt flow freely. There are salts that are naturally white, but they are the exception rather than the rule for what is readily available to consumers in North America. When salt is stripped of its trace minerals it is much easier for our bodies to end up overloaded with sodium because the body is still going to ask for the familiar source of minerals. Refined salt is a newer addition to our diets, especially when compared to how long we have been eating true salt. The imprint for seeking minerals from salt is built into your genetics because of your ancestors.
Biologically only a few plants require salt, this means a diet high in plants will require an outside source of salt. Animals, including humans, require sodium for nerve impulses, electrolyte balance, and fluid balance. Our bodies deplete sodium every time we cry, sweat, pee, ect. This means we constantly need to replenish sodium from our diets. Mentioning those 3 large categories don't do the importance of this mineral justice. Without sodium, our nerves cannot send signals back and forth. Every thought you have, every itch, every movement, requires sodium every time. Too much or too little sodium and the fluid balance in the body cannot be maintained. Too little water in the body and we get dehydration, if severe enough, we die. Too much water and conditions like edema occur, an excess of water will apply more pressure on internal organs while also causing pain due to swelling. Electrolyte imbalance can lead to problems such as seizures (if gone long enough), muscle twitches, and weakness. Plus it may place stress on organs like the heart because the nerves can't fire properly when there is an electrolyte imbalance. Remember, minerals are electrolytes and sodium is only one electrolyte in the group that humans need.
Dr. James DiNicolantonio, author of The Salt Fix gives a good interview here regarding the essential nature of salt in our diets.
