There are so many different varieties of salt on the market, but some are better for certain applications than others. So, let's go through some of the most common types of salt and their purpose.
Table salt: Ah... table salt, it's the most basic variety and what we picture when someone says "salt." Table salt is a refined type of salt that usually has iodine in it and anti-caking ingredients. It is mined and then dissolved into water, purified from imperfections, and then dehydrated; this process creates the uniform salt we know. It is useful for adding to food at the table because the small size of the granules can be evenly distributed without mixing and heating.
Kosher salt: Kosher salt is similar to table salt in that it is refined, but dissimilar in the aspect of having larger crystals and no additives like iodine. It did not get its name from it being kosher itself, but for its use in dry brining, or koshering, meat. Chefs prefer kosher salt because it is easier to pinch and feel for the amount.
Pickling salt: Especially around this time of year, you'll see a lot of canning and preserving recipes calling for pickling salt in brines. As the name suggests, it is used primarily in pickling. Similar to kosher salt, it has no additives like iodine or anti-caking agents that can make the brine cloudy or change its flavour. The difference is that pickling salt has smaller granules, making it quick and easy to dissolve.
Sea salt: Sea salt comes directly from evaporated seawater. Due to the differences in minerals from sea to sea, the salt from each can change dramatically. For example, the most famous of the sea salts is Maldon, which is made of water from off the southeast cost of England. Sea salt crystals are large and delicate, but you can find both flaky and fine varieties sold. The larger crystals are perfect for finishing food.
Fleur de sel: This is one of the fanciest varieties of salt that you can get your hands on. This salt comes in its natural form and is not crushed or ground. This type of sea salt is acquired through hand-harvesting salt deposits that have crystallized into a layer over top of salt evaporation ponds or marsh basins. Fleur de sel is high in mineral content and has a light briny flavour. These crystals tend to stick together, so it is used mainly as a finishing salt.
Pink (Himalyan) salt: This salt is distinguishable by its bright pink colour that stems from trace amounts of iron oxide, along with calcium, iron, potassium and magnesium. This salt is remarkably similar to regular table salt, but looks pretty as a garnish on your table.
Pink curing salt: Not to be confused with pickling salt or Himalayan salt, pink curing salt is used in the process of meat preservation to prevent spoilage. Generally made out of a combination of table salt and sodium nitrate, this salt its often used in making cured meats like ham, bacon, pastrami, and corned beef. Its characteristic pink colour comes from food colouring, which often makes its way into the meat it is used on, and is used to avoid confusion with regular table salt.
Black salt: Kala namak, or Himalayan black salt, is a type of salt that has been kiln-fired with a variety of other plants and minerals. Its dark hue is provided by the iron sulfide found in the mineral. Black salt has a high sulfur content, giving it a pungent smell and savoury taste. Kala namak is used mainly in South Asian cuisines, and has a special place in chaat masala spice mixtures. In addition to its flavour properties, this salt is also believed to be helpful for digestive ailments such as constipation, flatulence and heartburn.