Salted_ A Manifesto on the World's Most Essential Mineral, With Recipes - Mark Bitterman [21]
Understanding the mechanisms in our bodies responsible for taste sensation has been the objective of intense scientific research, yet we are only just cracking the code for how it works. Taste buds are made up of bunches of taste receptor cells, each with distinct abilities to respond to different taste stimuli. Contrary to what many of us were taught, there are no distinct areas of the tongue more attuned to one taste or another: we detect all flavors in all the areas of the tongue where tasting occurs, and we gain vital information about the characteristics of our food from the other surfaces of our mouth as well.
While we understand a good deal about taste perception, we do not completely understand the most fundamental mechanisms for sensing salt in our mouth, whether it comes through the taste receptor cells or a combination of these and other structures. Salt dissolves into ions of sodium and chloride on our food and in our mouths. The mouth starts to buzz. If you taste salt by itself, you will know what I mean. The overpowering generalized cellular reaction to sodium makes it harder for scientists to isolate what is happening in salt-receiving taste receptors that is different from what is happening in any cell. It is chemically possible that saltiness stimulates virtually all the tissues of the mouth. The best evidence suggests that a special form of voltage-gated sodium channel is involved but pinning this down has proved difficult because all cells, not just those engaged in taste, have voltage-gated sodium channels.
Also a mystery and a subject of great interest is salt’s impact on the sensation of other flavors. Add salt to something bitter or sour, and the bitterness or sourness is diminished. Add it to something sweet or umami, and those flavors can be accentuated. Salt not only tastes good in its own right, but it also improves the flavors of foods we need but might be less inclined to eat. Broccoli tastes better with salt. Mackerel tastes better. We may never fully unravel the billions of years of engineering that have resulted in a mouth that can receive so much pleasure from a single essential mineral.
SEA SALT, INDUSTRIAL STYLE
I believe in looking reality straight in the eye and denying it —Garrison Keillor
Industrial salt making aims for two things: low cost and purity of sodium chloride. Forty-eight percent of all salt produced in the United States in 2007 was in brine, according to the U.S. Geological Survey. Brine is the least expensive salt; it mostly feeds the chemical industry.
Rock salt makes up 34 percent of production. Rock salt is mined from the earth, usually using diesel-powered equipment, dynamite, and grinders in vast underground chambers. Rock salts are the residue of ancient, receding oceans and can be as pure as 99.5 percent sodium chloride. Minable inland rock deposits come in two primary forms: bedded salt and salt domes. Salt domes occur when stratified salt deposits are subjected to pressures that cause them to extend upward and downward vertically, sometimes more than 20,000 feet. Unlike salt domes, bedded salt is not very deep, but can extend horizontally over great distances. Most rock salt is used for road deicing, with some also going toward feedstock for animals. A small percentage is refined for use as food salt.
The purest salts are made by vacuum pan evaporation (they are sometimes called evaporated salts), in which a brine (produced by pumping water into underground salt deposits to dissolve the salt buried in the rock) is pumped back up to the surface. The water is processed with chemicals such as carbon dioxide and sodium hydroxide to precipitate out unwanted calcium and magnesium salts and any other minerals. The refined brine is then boiled off in series vacuum evaporators until salt crystals form. Crystals forming within the brine will generally be tiny, cubic, identical, and up to 99.99 percent pure sodium chloride. The condensed brine can also be pumped to open