edible salt

For sour salt, see: citric acid.

Edible salt is a mineral, one of the few rocks people eat. There are different forms of it: unrefined salt, refined salt, table salt or iodised salt. It is a crystalline solid, white, pale pink or light grey in colour, obtained from seawater or from rock deposits. Sea salt comes in fine or larger crystals. In nature, it includes not only sodium chloride, but also other vital minerals, including trace minerals. Rock salt which is edible after being refined, is grayish because it is less pure and contains more minerals. Salt craving is always trace mineral lack. Whatever its exact composition, salt is necessary for the survival of all living creatures, including humans. Water and salt regulate the water content of the body (fluid balance). Salt flavour is one of the basic tastes. Salt is required for life, but overconsumption can increase the risk of health problems, including high blood preasure. Salt is also used to preserve food.

History of edible salt

For the history of salt in America, see History of salt in America.

In the past, salt was difficult to obtain, but had a great importance in food preservation and as a vital food additive. Therefore, it was a highly valued trade item throughout history. Wars were fought over it, states were formed and destroyed because of it. Roman soldiers were partially paid with salt, and this is still evident in the English language as the word salary derives from the Latin word salarium that means payment in salt (Latin sal), as well as the phrase "worth one's salt". It was also of high value to the Hebrews, Greeks and other peoples of antiquity. 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. Cites, states and dukedoms along the salt roads exacted heavy duties and taxes for the salt passing through their territories. This practise has caused wars, it even caused the formation of cities such as the city of Munich in 1158 when the then Duke of Bavaria Henry XII, called The Lion, decided that the bishops of Freising no longer needed their salt revenue. Because of the gabelles, common salt was of such a high value that it caused mass population shifts and exodus, attracted invaders and caused wars. In the second half of the 19th century its price finally became more reasonable. The main reason for this was that it finally became possible to gain it by mining instead from the evaporation of seawater, as mining is the cheaper of the two processes. However, unrefined rock salt lacks many of the trace elements normally found in table salt, making it a poor substitute as an exclusive salt source. The deleterious health effects of the exclusive use of rock salt are similar to the effects of the total lack of salt in one's diet. Today salt is universally accessible, relatively cheap and iodized.

Forms of edible salt

Unrefined salt

Main article: Sea salt Unrefined sea salt is regarded by some as healthier than refined salt, although there are concerns that raw sea salt may not contain sufficient iodine salts to provide necessary micronutrition in areas where iodine deficiency is common.

Refined salt

Refined salt, that is nowadays most widely used, is mainly sodium chloride. Only about 7% of the refined salt is used as a food additive. The majority of it is sold for industrial use, from manufacturing pulp and paper to setting dyes in textiles and fabric, to producing soaps and detergents, and has great commercial value.

Production methods

The manufacture and use of salt is one of the oldest chemical industries. Salt is mined from deposits that were created after evaporation of salt lakes or is obtained as a brine by introducing water into the deposits to dissolve the salt and then pumping the solution to the surface. Salt is also obtained by evaporation of seawater, usually in shallow basins warmed by sunlight; salt so obtained was formerly called bay salt, and is now often called sea salt or solar salt. Most refined salt is obtained from deposits, however table salt is obtained from seawater. After the raw salt is obtained, at first chemical impurities are removed. During the refining, natural sea salt or rock salt is stripped of almost all the elements it contains, depending on the purity that should be reached. Anticaking agents are generally added at this point. Some anticaking agents used are sodium alumino-silicate and alumino-calcium silicate. (Note: there have been concerns raised about aluminum toxicity with these anticaking agents). This is followed by drying of salt. Major producers dry their salt in huge kilns where it is heated to temperature of about 650 C (1200 F), which changes its chemical structure. At the end, it is packed and distributed.

Table salt

Table salt is refined salt, that contains almost exclusively two or three chemical elements. The two most important of them are sodium (39%)and chloride (61%), combined together as NaCl. It also contains substances that make it free floating. It is mainly used in cooking and as a table condiment. However, the salt that is sold as a food additive, contains also other elements, notably aluminium, whose content is not allowed to exceed the maximum set by the national standards as well as international standards (WHO) for food quality.

Iodized salt

Iodized salt is table salt, that is enriched with iodine (sodium iodide). It is important to prevent the insufficient production of thyroid hormones (hypothyroidism), that causes cretinism in children or myxedema in adults and goiter, in areas where natural iodine is scarce.

Health effect

Sodium is one of the primary electrolytes in the body. Too much or too little salt in the diet can lead to an electrolyte disturbance, which can cause severe, even fatal neurological problems. Excessive consumption of sodium has also been linked to high blood pressure.