What is Kosher Salt?

“Kosher” salt has become a sort of shorthand for coarse salt, though not all coarse salt is used in kashering, as the process of salting meat according to Jewish dietary laws and traditions is called. The salt draws out any blood that lingers in the meat, and because certain types of salt absorb liquid quickly and efficiently, they have become known as kosher.

Today, the term usually is applied to two types of salt crystals.

One, sold under the brand name Diamond Crystal, is made using a method developed by J.L. Alberger in the 1880s. Alberger salt is made by dissolving and extracting underground deposits of salt. The brine is heated to about 290 degrees, forced through a graveler to remove calcium sulfate and then cooled. The purified brine is pumped into an enormous open pan, where tiny seed crystals of salt form instantly. Inverted pyramid-shaped crystals form on the salt seeds, and when all of the salt has precipitated out in this way, the remaining liquid--called bittern because of its bitter taste--is spun off and the salt is dried, screened and graded into sizes.

The coarsest size becomes Diamond Crystal kosher salt. The hollow pyramids absorb moisture quickly. They also dissolve rapidly, making this an ideal cooking salt.

Because of its shape, Alberger salt occupies more space than a similar weight of regular salt, which is to say that there is less salt in a teaspoon of Alberger salt than in a teaspoon of table salt.

Cargill Corp. owns both Diamond Crystal and the patent for Alberger salt; no other company can use the method. Other kosher salts are made by flattening table salt--small cubes of kiln-dried salt--into thin, hard wafers. Sometimes three or four wafers are fused together, creating a slightly larger flake. These types of kosher salt dissolve more slowly than other salts and thus take longer to bring flavors to the palate.