Sea salt, obtained by the evaporation of seawater, is used in cooking and cosmetics. Historically called bay salt,[1] its mineral content gives it a different taste[2] from table salt, which is pure sodium chloride, usually refined from mined rock salt (halite) or from sea salt. Areas that produce specialized sea salt include the Cayman Islands, Greece, France, Ireland, Colombia, Sicily, Apulia in Italy, Maldon in Essex UK[3], and Hawaii,[4] Maine, Utah, the San Francisco Bay, and Cape Cod in the United States. Generally more expensive than table salt, it is commonly used in gourmet cooking and specialty potato chips, particularly the Kettle Cooked variety.
Where mineral salt has been readily obtainable it has long been mined. The salt mines of Hallstatt go back at least to the Iron Age. However, it has not been readily obtainable everywhere and the alternative coastal source has also been exploited for thousands of years. The principle of the production is the evaporation of the water from the brine of the sea. In warm and dry climates this may be done entirely by solar energy, but in other climates fuel must be used. For this reason, sea salt production is now almost entirely an industry of Mediterranean and other warm, dry climates.
Such places are today called salt works, instead of the older English word saltern. An ancient or medieval saltern could be established where there was:
- Access to a market for the salt.
- A gently-shelving coast, protected from exposure to the open sea.
- A cheap and easily worked fuel supply; preferably, the sun.
- Preferably, another trade such as pastoral farming and tanning so that it and the salt could each add value to the other in the form of leather or salted meat.
In this way, salt marsh, pasture (salting), and salt works (saltern) enhanced each other economically. This was the economic pattern in the Roman and Medieval periods around The Wash, in eastern England. There, the tide brought the brine, the extensive saltings provided the pasture, the fens and moors provided the peat fuel, and the sun sometimes shone.
The dilute brine of the sea was largely evaporated by the sun, and the concentrated slurry of salt and mud was scraped up. The slurry was washed with clean sea water so that the impurities settled out of the now concentrated brine. This was poured into shallow pans lightly baked from the local marine clay, which were set on fist-sized clay pillars over a peat fire for the final evaporation. The dried salt was then scraped out and sold.
Gourmets often believe sea salt to be better than ordinary table salt in taste and texture, though one cannot always taste the difference when dissolved. In applications where sea salt's coarser texture is retained, it can provide different mouthfeel and changes in flavor due to its different rate of dissolution. The mineral content also affects the taste. It may be difficult to distinguish sea salt from other salts with a high mineral content, such as pink Himalayan salt, or grey colored rock salt. Sea salt is purified less than the high mineral pink salt.
Because sea salt generally lacks high concentrations of iodine,[5] an element essential for human health,[6] it is not necessarily a healthful substitute for regular iodized table salt,[7] which is usually supplemented with the element, unless another source of dietary iodine is available (such as dairy products or regular processed foods).[8] Iodized forms of sea salt are now marketed to address this concern. However, unrefined sea salt contains many minerals that regular iodized table salt does not contain, such as calcium, potassium, magnesium, sulfate, and traces of others (including heavy metals such as mercury, lead, cadmium, and strontium)[citation needed].
cosmetic and gourmet use, sea salts are also used as a main ingredient in the production of bath salts. These are used as bathing additives and are believed by some to possess therapeutic and healing properties.
Sea salts that are used in the production of bath salts are not just taken from any body of water. Some of the common properties of the location in which they are extracted are age, seclusion from human intervention, and mineral content. Common bodies of water in which these salts are extracted include the waters of the Himalayas, the Dead Sea, Pacific Ocean, Mediterranean Sea, and Utah's Great Salt Lake.