What is Salt?

Salt Crystal

Naturally formed salt crystals. Salt is a mineral that is composed primarily of sodium chloride. It is essential for animal life in small quantities, but is harmful to animals and plants in excess. Salt flavour is one of the basic tastes, making salt one of the oldest, most ubiquitous food seasonings. Salting is an important method of  food preservation.

Salt’s ability to preserve food changed the way people eat food. It eliminated the dependence on the seasonal availability of food and it allowed travel over long distances. It was also a desirable food seasoning. However, salt was difficult to obtain, and so it was a highly valued trade item, which followed the pull of economics along salt roads. Until the twentieth century, salt was one of the prime movers of national economies and wars. Today salt is almost universally accessible, relatively cheap and often iodized.

Salt production

On an industrial scale salt is produced in one of two principal ways: the evaporation of salt water (brine) or by mining. Evaporation can either be solar evaporation or using some heating device.

Salt Evaporation Pond

In the correct climate (one for which the ratio of evaporation to rainfall is suitably high) it is possible to use solar evaporation of sea water to produce salt. Brine is evaporated in a linked set of ponds until the solution is sufficiently concentrated by the final pond that the salt crystallises on the pond's floor.

Open pan Salt Making

One of the traditional methods of salt production in more temperate climates is using open pans. In an open pan salt works brine is heated in large, shallow open pans. Earliest examples date back to prehistoric times where the pans were made of ceramics, later examples were made from iron. This change coincided with a change from wood to coal for the purpose of heating the brine. Brine would be pumped into the pans, and concentrated by the heat of the fire burning underneath. As crystals of salt formed these would be raked out and more brine added.

The open pan salt works has effectively been replaced with a closed pan system where the brine solution is evaporated under a partial vacuum

History of Salt

The Roman Republic and Empire controlled the price of salt, increasing it to raise money for wars, or lowering it to be sure that the poorest citizens could easily afford this important part of the diet.

Already in the early years of the Roman Republic, with the growth of the city of Rome, roads were built to make transportation of salt to the capital city easier. An example was the Via Salaria (originally a Sabine trail), leading from Rome to the Adriatic Sea .The Adriatic Sea, having a high salinity due to its shallow depth, had more productive solar ponds compared to others.
During the late Roman Empire and throughout the Middle Ages salt was a precious commodity carried along the salt roads into the heartland of the Germanic tribes. Camels traversed the Sahara bearing salt to inland markets and sometimes trading salt for slaves.

During more modern times, it became more profitable to sell salted food than pure salt. Sources of food to salt went hand in hand with salt making. The British controlled saltworks in the Bahamas as well as North American cod fisheries. This may have added to their economic clout during their 19th century imperial expansion period. The search for oil in the late 1800s and early 1900s used the technology and methods pioneered by salt miners. In the second half of the 19th century industrial mining and new drilling techniques made the discovery of more and deeper deposits possible, increasing mine salt’s share of the market. Although mining salt was generally more expensive than extracting it from brine via solar evaporation of seawater, the introduction of this new source reduced the price of salt due to a reduction of monopolization. Extraction of salt from brine is still heavily used: for example vacuum salt produced by British Salt in Middlewich has 57% of the UK market for salt used in cooking.

Types of Salt

There have been two main sources for salt: sea water and rock salt. Rock salt occurs in vast beds of sedimentary evaporite minerals that result from the drying up of enclosed lakes and seas. Salt beds may be up to 350 m thick and underlie broad areas. In the United States and Canada extensive underground beds extend from the Appalachian basin through parts of Ontario and under much of the Michigan basin. In the UK underground beds are found in Cheshire and around Droitwich.

Salt is extracted from underground beds either by  mining or by solution mining, using water or brine. In solution mining the salt reaches the surface as brine, which is then turned into salt crystals by evaporation.

Facts and Tips on Salt

  • When using a Cole and Mason Salt Mill always use Sea Salt Crystals.
  • We recommend using Maldon Sea Salt Crystals or our own brand of salt
  • If a salt mechanism has worn through in a short period of time, one of the contributing factors can be the use of Rock Salt. Rock Salt will wear down the mechanism very quickly, as it is too harsh for our mills. Although on many makes of Rock Salt packaging it will state that this type of salt is suitable for all grinders, this is not the case with Cole & Mason Mills.
  • Likewise, the use of Sea Salt Flakes is not recommended as this type of salt will coagulate within the mechanism and will cause the grinder to fail.
  • Also do not use any type of salt that is of a ‘moist’ consistency or texture ie French Sal de Mer, as this type of salt will also coagulate in the mill. All salt must be free flowing and kept in a dry atmosphere.
  • Salt Mills will benefit from (time to time) putting a VERY small amount of cooking oil between your finger and thumb and rubbing it around the threaded part of the mill shaft. This will stop any corrosion caused by the salt between the shaft and the screw knob