What, Exactly, Is Kosher Salt? (Plus How to Use It)

At one time it was so easy. If a recipe called for salt, you grabbed the box of Morton and went about your business. But now, one must carefully read the fine print: does the recipe require regular table salt or sea salt or the most recent salt du jour, kosher salt?
Before you go out and purchase yet another type of salt, in the interest of simplicity, you should know that:
A) all salt is kosher by definition, meaning it’s accepted by Jewish law as fit for eating and drinking, although the salt you see called kosher salt is its own kind of salt;
B) all salt is comprised of the same two basic minerals — sodium and chloride;
C) and, with the exception of a few trace elements, all salts are nutritionally equal by nature. While there are subtleties of flavor and minuscule amounts of “good for you” minerals like iron, potassium and calcium, at the end of the day it comes to preference.
But — and this is a big but — while table salt and sea salt can be exchanged on a one-to-one ratio, kosher salt definitely can not.
Kosher salt is a coarse grain salt with large, chunky crystals. The bigger granules mean that there is a lot less actual salt in your measuring spoon and, by default, a lot more air between the granules taking up space.
The basic rule of thumb for substituting table or sea salt for kosher salt is to cut the amount of table or sea salt by half. If your recipe calls for a tablespoon (the equivalent of three teaspoons) of kosher salt, you would use 1½ teaspoons of regular table salt or fine sea salt.
Professional chefs often choose kosher salt because the large grains are easier to pinch and scatter and they dissolve quickly. For the record, since my cabinet is already overflowing with jars of seasoning, I routinely use fine sea salt and adjust the recipe accordingly. I’ve had no complaints thus far.
Cooking really doesn’t have to be complicated. Make sure you read the recipe carefully (I learned that one the hard way) and when in doubt, err on the low side. You can always add more salt later.
How refined is your palate? Take this salt test and see if you can taste the difference. —Karen