What defines kosher salt is its large, coarse grains. The term is a shortening of koshering or kashering salt, because its traditional use is to remove the blood from meat, as required by Jewish dietary laws. The large salt crystals draw out blood without dissolving much, which keeps the meat from becoming oversalted. And the coarse grain is perfect for making a salt crust, a traditional method for cooking whole fish that results in especially tender, juicy flesh.
Like table salt, most kosher salt is industrially produced. It isn’t iodized, but might contain anticaking agents, which will be listed on the label. The two dominant brands on the market, Morton’s and Diamond Crystal, are manufactured using different processes, which makes them extremely dissimilar. Morton’s has dense, heavy cubes that pack together tightly in a measuring spoon. Diamond Crystal, the darling of professional chefs, is shaped into light flakes that remain somewhat separate.
When measured by volume (teaspoons, tablespoons, pinches), Morton’s is twice as salty as Diamond Crystal (see this chart for more salt comparisons). Substituting one for the other can wreak havoc on your recipe, rendering a dish too salty or not salty enough. Weighing solves this problem, because all salts can be used interchangeably by weight.
Common Sea Salt
Most inexpensive sea salt is industrially produced from seawater. It can be processed into fine granules like table salt, or coarser cubes to be either used in a salt grinder or added directly to pasta water, soups and stews. Sea salt is sometimes coated with anticaking agents, but, since it doesn’t usually contain iodine, it can have a cleaner flavor than table salt. Fine sea salt is often used in baking because of its ability to dissolve quickly, and can be used in place of table salt in cooking.
Traditional Sea Salts
Built on age-old traditions, sea salts like fleur de sel, sel gris and flaky salt are all made by evaporating seawater, either in the sun in warm climates, or by boiling. They can have a variety of trace minerals that add character, color and texture. But because they’re usually expensive and don’t have a uniform crystal size or salinity, they’re not often called for in recipe ingredient lists. Used as finishing salt, traditional sea salts can bring plenty of textures and flavors to the table.
