Odourless and sharp tasting, salt crystals are brittle and soluble in water. They are made up of sodium (40%) and chloride (60%), whence the scientific name for salt, sodium chloride. Like water, salt is essential for the functioning of the human body. It has long been a precious condiment and food preservative. Given its critical importance for humanity, it has been referred to historically as "white gold." There are two types of sodium chloride: rock salt and sea salt.
Rock salt, or halite, is mined from natural deposits formed by the shrinking of seas during geological periods. Often, water is pumped into specially drilled wells to dissolve the rock-salt deposits. The brine is then pumped to the surface and heated until the water evaporates. The resulting product is white, as it has lost virtually all minerals other than sodium and chloride.
Another technique consists in hauling the salt to the surface for refining. Table salt is halite that has been purified by a chemical process that prevents the mineral from absorbing moisture. Ninety percent of the earth's water is salty, with each quart of seawater containing about 30g of sodium chloride.
Sea salt generally comes from salt marshes, basins where seawater has been trapped and is allowed to evaporate under the combined effects of sun and wind. It is also produced from inland seas such as the Red Sea, Dead Sea, and Great Salt Lake, which have a higher than normal salt content.
Sea salt is greyish, as it contains traces of minerals such as calcium, magnesium, potassium, bromides, and other elements. Some chefs feel that these substances give sea salt a stronger, "purer" taste. They are often removed, however, as they fetch a higher price when sold separately.
Salt is unequally distributed around the planet. For centuries, it was considered a luxury item accessible only to the wealthy.
In addition to using it to preserve fish, olives, cheese, and meat, the Romans used it to pay their soldiers – a practice at the origin of the word “salary.” Wars have been fought between nations seeking reliable supplies of sodium chloride. The salt trade was a factor behind the development of modern civilizations and the opening up of trade routes.
Salt has been and continues to be used in religious rituals as well as for medicinal purposes. Many people used to think that it warded off evil spirits and demons responsible for illnesses. In China, salt was formed into bars, which were stamped with the emperor's seal and used as currency. During the 14th century, France instituted a salt tax that forced people to buy a certain amount of the product each year from a state monopoly. Three centuries later, this socially unfair tax helped trigger the French Revolution. Abolished in 1790, it was reinstated by Napoleon and remained in effect until after the Second World War.
Today salt is plentiful and cheap. In many countries, along with bread, it remains a symbol of friendship and hospitality. Its cultural significance is underlined by common expressions such as “salt of the earth” and “take (a story) with a grain of salt.” Sal, the Latin word for salt, has spawned a number of derivatives, including Salary, from salarium, meaning payments made to purchase salt as well as salt rations allotted to Roman soldiers; Sausage, from salsus, meaning salted; Salami, from the Italian word salame, derived from the Latin salare, meaning to salt.
Sodium plays a number of vital roles in the human body, contributing to the metabolising of protein and carbohydrates, the transmission of nerve impulses, muscle contraction, hormone regulation, consumption of oxygen by cells, control of urine production, thirst, and the production of liquids (blood, saliva, tears, perspiration, gastric juices, bile). Salt is also essential for the production of hydrochloric acid in the stomach.
Eating salty foods makes us feel thirsty, as the body reacts to excess salt by requiring extra liquid. Salt consumption is very high in industrialized countries. Unfortunately, over-consumption frequently has a negative impact on health, contributing to hypertension and cardiovascular diseases among people at risk.
Excessive salt consumption can also lead to water retention, which boosts the heart rate and can increase blood pressure above recommended levels. You are therefore best advised to limit your salt intake, particularly as enough salt is naturally present in most foods to meet the body's normal needs. People with strictly vegetarian salt-free diets and individuals who suffer from diarrhoea, vomiting, or heavy prolonged sweating however, could be suffering from salt deficiency.
Most of our salt intake (77%) comes from food products. Salt is said to be invisible, because we are often unaware of just how much salt is added to foods and our ability to detect saltiness decreases as we become accustomed to the seasoning. Less than one fourth or even one third of our total sodium intake comes from the salt we voluntarily sprinkle on our food.
Sodium chloride is generally marketed as coarse salt, fine-grain salt, crystal salt, or table salt. Table salt can comprise both halite and sea salt, and is often iodised.
Salt is almost always treated with additives (magnesium carbonate, magnesium oxide, calcium silicate) to prevent it from absorbing moisture and ensure that it remains free flowing and granular.
Coarse salt, which may be less refined, is used by the food industry and in certain dishes and marinades. Various specialty salts for specific uses are available in stores: for example, tenderiser (salt fortified with enzymes such as papain, used to tenderise meat), salt enriched with sodium nitrate or a combination of sodium nitrate and potassium nitrate (used to cure meats and as a preservative), and flavoured salt (garlic salt, onion salt, celery salt, etc.).
Various salt substitutes with little or no sodium chloride are available also. They often contain potassium chloride, a substance that leaves a bitter aftertaste and, particularly if consumed in large quantities by people who suffer from kidney disorders, can cause imbalances.
Keep salt in an airtight container in a dry place. Add a few grains of uncooked rice to a saltshaker to prevent the salt from caking (the rice absorbs moisture).
Salt is a natural preservative which inhibits the growth of moulds and bacteria. It literally pulls the life-sustaining moisture from those harmful bodies, making them unable to grow or reproduce. When used as a condiment or ingredient, it brightens food flavors and facilitates a balance between sweetness and acidity by decreasing the sourness of acid and increasing the sweetness of sugar.
You will find that some recipes call for a specific type or grind of salt beyond ordinary table salt. In some cases, it will not matter if you use table salt, but in others, it can make or break the dish. Your best bet is to follow the recommendation of the recipe author to achieve the desired result.
It may seem strange to think of salt being used as a fat-free method of cooking, but it works. Encase meat in a crust of salt and the salt will draw out and absorb the fat, while sealing in moisture and flavour, very much like old classic dishes using clay. The salt casing also reduces cooking time anywhere from one-third to one-half.
How much salt do you need? Here are some general guidelines…
- 1 teaspoon per litre for soups and sauces.
- 2 teaspoons per 450g for boneless raw meat.
- 1 teaspoon per 4 cups flour for dough.
- 1 teaspoon per two cups liquid for cooked cereal.
- 1 teaspoon per 3 cups water for boiled vegetables.
- 1 Tablespoon per 2 litres of water for pasta.
- 1 Tablespoon flaked salt = 2 teaspoons table salt.
Salt is used for a number of purposes in food preparation. Its effectiveness in inhibiting bacterial action and mould makes it an excellent preservative (in delicatessen meats, marinades, cheese, fish, etc.). It stabilizes the colour, taste, and texture of foods, particularly vegetables. It slows down yeast growth in breads, cakes, cookies, and other baked goods. It masks bitter tastes and heightens flavour. It stimulates the appetite. Indeed, far from being merely a seasoning, salt has an estimated 10,000 different uses.
Processed food, restaurant food, and certain medications (laxatives, analgesics, and some antacids) are high in salt and should be consumed with moderation.
People wishing to cut back their sodium consumption should also avoid highly salted foods such as commercial soups and stocks; smoked, salted, and canned meats and fish (anchovies, sardines); marinades; sauerkraut; kelp; commercial sauces (soy sauce, chilli sauce, ketchup, prepared mustard); foods sprinkled with salt (chips, crackers, pretzels); celery, garlic, and