Sea salt

Chemical composition of sea salt by mass

Sea salt harvesting in Pak Thale, Phetchaburi, Thailand

Sea salt, salt obtained by the evaporation of seawater, is used in cooking and cosmetics. Historically called bay salt or solar salt, its mineral content gives it a taste which differs from that of table salt, which is pure sodium chloride, usually refined from mined rock salt (halite) or from sea salt. Generally more expensive than table salt, it is commonly used in gourmet cooking and specialty potato chips, particularly the kettle cooked variety (known as hand-cooked in the UK/Europe).

Historical production

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 production is evaporation of the water from the brine of the sea. In warm and dry climates this may be accomplished entirely by using solar energy, but in other climates alternative and often expensive fuel sources must be employed. For this reason, sea salt production is now almost entirely an industry of Mediterranean and other warm, dry climates.

"Fleur de sel" sea salt, Île de Ré.

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:

1. Access to a market for the salt,
2. A gently-shelving coast, protected from exposure to the open sea,
3. An inexpensive and easily worked fuel supply, preferably the sun,
4. Another trade such as pastoral farming or tanning which could benefit from the nearness of the saltern (by producing, for example, leather or salted meat) and in turn provide the saltern with a local market.

In this way, salt marsh, pasture (salting), and salt works (saltern) enhanced each other economically. This was the pattern during 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.

Manual salt collection in Lake Retba, Senegal.

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.

Current production

Areas that produce specialized sea salt include:

• Cayman Islands
• Colombia
• Greece
• France
• Ireland
• Italy (Apulia, Romagna, Sardinia, Sicily)
• South Korea
• United Kingdom (Maldon, Essex)
• United States (Hawaii, Maine, Utah, the San Francisco Bay, and Cape Cod)
• Canada (Nova Scotia, British Columbia)
• Philippines
• Israel (Dead Sea)
• Japan
• Mexico (Guerrero Negro, Baja California Sur)
• Brazil

Composition

Sea salt is primarily composed of the following ions, listed in order of descending abundance by weight:

Chloride (Cl-)	55.03%
Sodium (Na+)	30.59%
Sulfate (SO42-)	7.68%
Magnesium (Mg2+)	3.68%
Calcium (Ca2+)	1.18%
Potassium (K+)	1.11%
Bicarbonate (HCO3-)	0.41%
Bromide (Br-)	0.19%
Borate (BO33-)	0.08%
Strontium (Sr2+)	0.04%
Everything else	0.01%

Although the salinity of sea water varies worldwide, the relative proportions of its constituent ions remain constant.

Taste

A commercial package of sea salt

Gourmets often believe sea salt to have a better taste and texture than ordinary table salt, although one cannot always taste the difference when it is dissolved. In applications where sea salt's coarser texture is retained, it can provide a different mouth feel 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 untreated salts, such as pink Himalayan salt, or grey rock salt. Sea salt is less purified than high mineral content pink salt.

Health

The health consequences of ingesting sea salt or regular table salt are the same.

In traditional Korean cuisine, so-called "bamboo salt" is prepared by roasting salt at temperatures between 800 and 2000 °C in a bamboo container plugged with mud at both ends. This product absorbs minerals from the bamboo and the mud, and has been shown to increase the anticlastogenic and antimutagenic properties of the fermented soybean paste known in Korea as doenjang.

Iodine, an element essential for human health, is generally present in negligible amounts in sea salt. However, rock salt, which naturally lacks iodine compounds compared to sea salt, is iodized industrially for use in treatments to prevent goitre and other iodine deficiency syndromes. The concentration of iodine in sea salt varies according to its provenance.

A salt mill for sea salt.

See also

• Sodium chloride
• Seawater
• History of salt
• Salt evaporation pond
• Bath salts