Most kosher sea salt is kosher, but not all kosher sea salt is kosher. Each type of kosher salt has its own unique production process and its own, unique way of adding its minerals and other ingredients to sea water. This is one of the differences between kosher sea salt and table salt. Sea salt has no additives added to it during the production process and table salt does. The concentration of these chemicals is too high for the body to absorb so sea salt is often left on the table where table salt is banned.
There is some controversy over which kosher salt is considered kosher. Most kosher sea salt is indeed kosher, however its production processes differ from kosher sea salt which is generally smoked over a fire. The larger, natural mined granules do not lend themselves well to kosher salt shakers, so it’s often served in large ramekins on the table. This makes kosher salt less practical for cooking and eating kosher meat or kosher fish. In climates where ambient temperatures are high, kosher salt won’t dissolve properly in water and table salt does.
Most kosher salt is used as an ingredient in kosher cooking. Many kosher cooks use kosher salt in their recipes as a cheap and effective cooking agent. This is because kosher salt tends to be much cheaper than sea salt have contrasting effects on the palette when cooked. Sea salt goes brown on the outside and white on the inside which some people find very unpleasant; kosher salt goes blue-green and is not nearly as pungent. This makes kosher salt a much more versatile seasoning agent than sea salt.
The main difference between kosher salt and sea salt is the manufacturing process. Sea salt is harvested by gathering the saltwater from the sea floor and then drying it in a specialized oven to evaporate the moisture. This leaves behind large crystals that have very little in terms of magnesium and chloride content. The manufacturing process also makes kosher salt highly sensitive to high temperatures, so it’s not advised for cooking or baking.
Most kosher salts are harvested by hand, which greatly minimizes chemical alteration of the mineral content. During the koshering process, a number of environmental variables come into play. Salt mineralization can take place due to heat, pressure, air, water, and even vibration. These variables affect the minerals and ultimately the taste of the salt. The greatest changes in the minerals occur during harvesting, drying, and production. High temperatures, low humidity, and aggressive drying methods all alter the minerals and flavor of kosher salt, making koshering process a delicate balancing act.
Some kosher sea salt manufacturers add a small amount of iron, manganese, and zinc to their salt. Iron and manganese are heavy metal additives that have the ability to increase the brine water concentration of the kosher salt. In addition, these metals are needed to boost the absorption of other trace minerals like calcium and magnesium in the salt. Table salt, on the other hand, contains no additives because table salt is derived from seawater and there are no other necessary elements to enhance the flavor.