What is kosher salt? Hold up: Before we get to that, what the hell is "iodized salt," the stuff that is not kosher salt but is in basically every salt shaker ever? Well, after consulting with my friend Wikipedia, I have learned that iodine is the heaviest stable halogen element, and was discovered by my other good friend Bernard Courtois in 1811. Cool. What I definitely do know is that iodine doesn't taste great, and nobody wants bad-tasting things mixed into their salt.
So, to recap, salt with iodine tastes bad, and you shouldn't use it. Kosher salt, on the other hand, is iodine-free, and you should use that instead. If you remember one thing, remember that, and everything you cook will taste better.
OK, but other than not having iodine in it, what is kosher salt, anyways? Is it blessed by a rabbi? Is it actually kosher? Well, it can be. But really, kosher salt is called kosher salt because the size of its crystals is ideal for drawing out moisture from meat, making it perfect for use in the koshering process. That’s also why we love to use it for cooking almost everything. Kosher salt is the MVP of our breakfast, lunch, and dinner seasoning game.
Crystal size isn’t something you normally think about when looking at a finer salt like kosher (or even finer table salt). But you should. We also steer clear of iodized table salt because, in addition to that unpleasant iodine flavor, the crystals are tiny and extremely compact. That means there is literally more salt in a pinch than there is with kosher salt. Smaller crystals dissolve almost instantly, making over-salting food a lot easier to do.
Kosher salt, on the other hand, has slightly larger crystals and therefore a more pinch-able, easy to control texture. We use it any time there’s a seasoning moment while cooking, whether it be salting pasta water or seasoning a whole chicken pre-roast.
But even within the kosher salt field, crystal size and shape varies from brand to brand. In the BA Test Kitchen, we use Diamond Crystal kosher salt, which has a distinctly different texture from Morton's Kosher—another very common brand. Morton’s crystals are denser and more pebbly than Diamond’s flatter, pyramid-like crystals. That means that there’s actually more salt by weight in a cup of Morton's than there is in a cup of Diamond. Which is why you'll notice that, whenever a significant amount of kosher salt is in play in a recipe, we'll tell you how much salt to use depending on which brand you're using. See, crystal size matters.
But what matters even more is that you pick a salt brand and stick with it. Seasoning is all about consistency, and salting food with an unfamiliar salt is a lot like driving someone else's car—you can do it, but it just doesn't feel the same. You want a pinch of salt to be the same pinch of salt every time. Just ditch the iodine, pick a brand of kosher salt you like, and start seasoning like a champion. Because when it comes down to it, you are.