Salt is the essence of the sea: sometimes mined from ancient, long-dry oceans, sometimes processed from living ones by drying in the sun. The oceans themselves formed long ago in the earth’s prehistory. As volcanoes vented hydrochloric acid and other chlorine-containing gasses, the rivers washed sodium, calcium, magnesium, and other light metals down into the valleys. Calcium and the others are consumed by sea creatures to form shells, which persist on as limestone, and the growing ocean is enriched in the elements that are both highly soluble in water and not used up by any living creatures: sodium and chlorine, or salt.

One could make a poetic argument about the need mammals have for the long-left briny seas of our birth, but all that needs to be said is that salt is essential for life.[1] Wars have been fought over salt. Fortunes and crowns have been made and lost over salt. Roman soldiers were paid a salary, so named because it came partly in salt, and they patrolled and guarded the Via Salaria, “Salt Road” that led to Rome along the Adriatic Sea.

Colors of Salt

Some salt (mostly rock salt) comes in different colors. The pink tint of Himalayan rock salt is caused by a small amount of iron oxide, while more iron-bearing clay in Hawaii turns it red. Smoke turns the salt brown as it adds flavor. Black salt is colored by ash, volcanic in Hawaii and from plants when salt is made from seaweed or salty herbs. Celtic sea salt has higher levels of magnesium and calcium which give it a greyish hue. Most consumers of salt would take what they could get locally and cheaply, but the may be a market among the very rich consumers for a display of wealth in uniquely colored salt.

To the Salt Mines!

Rock salt is mined from the ground where the old oceans laid it down between layers of sedimentary rock like sandstone or limestone. (There is a gigantic salt mine underneath Detroit, Michigan, USA). The work was, and is still, dusty and dry. The constant contact with salt is actually dangerous because of salt’s ability to pull water from living tissue and fatally alter the body’s blood chemistry. In ancient China, eating a pound of salt was a favored method of committing suicide: it would have been relatively easy for a miner to die just from breathing the salt. In Rome and elsewhere, the difficulty and danger of the task meant slaves worked the mines (a poor worker would not be worth his salt).

Mining the Sea

The ocean is about 3.5% salt by weight, and many cultures have extracted salt from the sea. Closer to the equator, where seawater evaporates much more quickly than rain replenishes, salt can be produced by baking shallow pans of seawater in the sun. Further north, the sun can evaporate enough water to turn the sea to brine, but fire must be used to finish the job. Salt has been produced in Essex, England, this way for centuries in shallow clay pans near the sea. An apocryphal story places the origin of the Essex salt trade with a Roman Centurion whose bath was prepared too hot and crystallized salt. The Roman trade changed entirely to the production of “sea salt” rather than rock salt mining, with a distinctive metal pan made from lead (which resists salt corrosion much better than iron or most other metals).

Food preservation

Of all the methods of preserving food available to the ancient world, nearly all required salt in some quantity. Dehydration was a primary preservative- salt would help speed the drying process by drawing water out of the cellular structure of the meat or vegetable salted. Salt could prevent spoilage as well, and in the same manner: drawing water out of a bacterial cell causes it to implode and die. Preserving by pickling or fermentation was also sped by salt drawing water out of the food and simultaneously preventing contamination with bacteria that would produce unpleasant flavors or smells (the yeast that does the work of fermentation is stronger and less affected by salt than the spoiling bacteria).

Combating Scarcity

Faroe Islands settlement - Nell Frizzell

But what if salt cannot be easily obtained locally, and cannot be imported? Located in the cold and wind-raked North Atlantic, between Scotland and Iceland, the Faroe Islands have learned to exercise the resources they have in plenty- salt air and cold winds- in exchange for the wood and salt they lack.[2] The cold wet air means that seawater can hardly be evaporated into salt, and the scouring of the wind limits the native vegetation to little more than shrubs. Some peat and turf could be harvested to burn, and the tundra does support sheep (which even today outnumber the Faroese) whose dung was the only replenishable fuel source on the island for centuries. The production of a ton of salt from seawater requires the burning of a ton and a half of wood- an insurmountable obstacle for the Faroese.

Salt could be produced in limited quantity, by drying and burning kelp seaweed. The ashes are about 10% salt, which can be extracted by rinsing with water. There is some evidence that such burnt seaweed was used on occasion for preserving meat, but more common methods survive today. In Iceland, sheep’s dung still is used to prepare traditional smoked lamb, called hangikjöt, but on the Faroe Islands even this resource was scarce enough to demand a different approach. Skerpikjøt, translated as “meat sharpened by cold and wind”, is the Faroese solution to preserving meat without salt. Sheep are butchered in the fall, and their mutton left to slowly dry and age in the wind in open shacks called hjallur all winter long.

Skerpikjøt - Jan Egil Kristiansen

Skerpikjøt is crude fare; most modern first world citizens would hesitate when presented with a piece of cold-fermented and smelly aged lamb, but it provides an interesting window into the theme of scarcity that runs through the survival game genre. What do you do when you can't have something as elementary and essential as salt? The Faroese have shown us a way to preserve meat while doing without.

Worth His Salt

As with all essential resources, there is opportunity in the salt trade. The production is easy enough- at the right latitude and in the right climate, all that is required is the ocean, and pan, and time. Efficiency could be gained by a mechanically-inclined saltmaster willing to invest in mass production: furnaces, wind and water mills, and skilled labor.

Transporting that salt to the far-away cities that have no nearby ocean is another matter- theft must be considered, and if the cargo gets wet it will be lost. Perhaps it would be better to trade in the goods produced with salt, if possible: cheese, butter, hams, or salted fish. One thing is sure- if Venice could build a merchant empire by exchanging salt for spice, the enterprising merchant could do worse than to start a new trade in salt.

References/Further Reading

1. E. Ritz, “The history of salt—aspects of interest to the nephrologist,” Nephrology Dialysis Transplantation, 11 (1996) Link

2. K. Oslund , “Scarcity in the Arctic: A Colonial Construct?,” pp. 26-36 in The Imagination of Limits: Exploring Scarcity and Abundance, ed. F. Felcht and K. Ritson, (2005) Link

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