Salt

sodium chloride, a white, granular substance used to season and preserve food. Salt is a crystallized compound that plays a major role in regulating the body's fluid balance, making it essential to human life. It is used as a seasoning, preservative, cooking medium (for instance, salt-crusted fish) and cooling agent (for example, when making ice cream). Salty is one of the five basic tastes, the others being bitter, sour, sweet and umami. Salt comes from two basic sources: underground deposits, which are mined, and seawater, which is evaporated. This produces two kinds of salt, rock salt and sea salt. Both run the gamut in terms of texture, from coarse to finely grained.

The very first tax was a levy on salt, imposed by Chinese emperor Hsia Yu in 2200 BC. In ancient China, even coins were made of salt. Egyptian mummies were preserved using salt. Roman legionnaires were paid in salt, hence the word "salary." Other words, such as "sauce" and "salad" are also derived from it. The expression "not worth his salt" came from payment in salt for a slave. There are more than 300 mentions of salt in the Bible. Jesus called his disciples "the salt of the earth", a testimonial observed during Roman Catholic baptismal ceremonies by placing a few grains of salt on the child's tongue. The main sources of salt in ancient times were dry coastal areas near the Mediterranean. Early trade routes (these and many of the first roads were established for transporting salt) centered around Spain, Italy, Greece and Egypt. Many of the caravan trade routes were developed to transport salt, and ancient cities, such as Genoa, Pisa and Venice, became salt market centers. The French salt tax, known as la gabelle, is said to have played a role in provoking the revolution in 1789. Salt was highly charged politically in India under British rule, when the government's monopoly on the sale and production of salt required that Indians buy salt from the government, at its rates, when salt could be found easily and for free. Mahatma Gandhi led his famous "long march" and general strike against this imposed salt tax. Salt changes the density of water, raises its boiling point and lowers the freezing point to below zero. Salt is used to draw out water and bitterness from cucumber and eggplant. Although cooks have always been taught not to salt a marinade or to only salt meat just before cooking because salt has a tendency to draw moisture from food, it has become fashionable to salt food, particularly meat, early, both in a marinade and even a day before cooking, for what amounts to a short "cure." The flesh changes color, texture and flavor without excessive loss of moisture. Salt's best-known contribution has been to food preservation, which preceded refrigeration. See also salt substitute.

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