If a recipe specifies kosher salt, is somebody having a laugh, or is there a gastronomic reason to use it?
Pablo, Lancaster
Kosher salt is not actually “kosher” (as in, it’s not religiously treated). Historically, the name stems from the Jewish practice of removing surface blood when dry brining meat (such as with brisket), and that process is known as kashering. Because of this kind of salt’s larger grain size, it dissolves more slowly and evenly, which in turn ensures a more even brining. It also doesn’t contain any additives or preservatives, so has a very clean, er, salty taste.
In practical terms, then, the coarseness and consistency of kosher salt grains also mean they are easier to handle and hold in your fingertips. This gives the cook a greater level of control, because they can salt ingredients much more evenly, unlike when you use fine sea salt, for instance, which has an annoying tendency to pour everywhere or clump up.
As a general rule, I use fine sea salt in the likes of sauces and pickling liquids, because it’s easy to measure by the teaspoon and because it dissolves much more quickly than other salts; I use a coarser salt such as kosher to season meat, fish and vegetables before cooking; and I use a flaky sea salt with larger, uneven crystals to finish off dishes. But beware! One teaspoon of fine sea salt is not the same as one teaspoon of diamond crystal kosher salt, and is, in fact, twice as salty.
At the end of the day, however, it doesn’t really matter what kind of salt you use at home, so long as you are aware of what it is and how it behaves.