Are Table Salt, Sea Salt, and Kosher Salt Interchangeable?
If we’re talking underrated cooking ingredients, salt would top the list—we only seem to notice when there’s too much or not enough, which just isn’t right. If you’ve ever been down the spice aisle, you know that there are tons of different types of salt out there, and our inclination is usually to reach for the cheapest one. While all salt is technically just structural variations of sodium chloride (remember middle school science?), it can actually be worth splurging on some of the fancier salts (as in, the ones that come in jars instead of cardboard boxes) for adding flavor and textural oomph to everyday dishes. Here's a breakdown of the most common salts you'll encounter in the supermarket or specialty shops, and what purpose each best serves in your kitchen.
The most refined salt, this is the stuff that’s probably in your saltshaker at home, or in the cardboard carton on the shelf, usually labeled “iodized.” It’s made by a solution mining: pumping water through salt deposits underground, and then evaporating the water once the brine reaches the surface. It has a very small crystal size, is mixed with additives to prevent caking, and in the U.S., you’ll usually find this salt iodized for health purposes. It’s usually what most recipes assume you’re using measurement-wise, and it’s the cheapest kind of salt you’ll see at the supermarket. The grain size works well for baking—it dissolves readily meaning a more evenly distributed saltiness.
You’re probably most familiar with this salt if you’ve ever made ice cream (or have had your streets salted during freezing temperatures—but that’s not the edible kind). Because it has a larger, coarser crystal size than table salt, it doesn’t dissolve as easily, which is why it’s used to hold a cold temperature. This is what you’ll find in the pre-loaded salt grinders that you may have at your dining table. It’s not iodized, and rock salt is deep-shaft mined from deposits underground, meaning it has minerals that aren’t normally found in table salt. The color will vary depending on where it’s mined.
This variety of rock salt doesn’t contain iodine or additives, and it dissolves a little easier than crude rock salt because of the smaller crystal size and structure. Traditionally used to preserve meats, you can usually substitute your table salt with kosher salt in your everyday cooking if you prefer the texture, but it doesn’t change too much flavor-wise. Be careful when seasoning though: If you’re substituting kosher for table salt, you’ll need to use a little more to reach the same level of saltiness. It’s also important to note that the crystal size and shape can vary between brands of kosher salt, making some “saltier” than others.
Sea salt is extracted by—you guessed it—evaporating seawater. If it’s made by a process involving intentionally boiling seawater, it’s called refined sea salt. And sea salt extracted through a process in which the sun dries out the seawater is considered unrefined, and usually contains minerals not found in the refined salt like calcium, magnesium, and potassium. This gives it a slightly more complex flavor and grayer color. Sea salts tend to fall on the pricier side, and the flavor can depend on what sea it’s been extracted from—save this salt to sprinkle on top of dishes after you’re done cooking to make flavors really pop.
This sea salt comes from marshes in Normandy, France, and is usually gray-ish in color because of the clay that it’s harvested from. Fleur de sel is sel gris’ delicate, flaky, more sophisticated cousin. It’s collected from the same places—except it’s harvested from the rocks that surround the marshes so there’s no clay, meaning a whiter color and flakier texture. These salts are the ideal “finishing salts,” meaning they’re usually sprinkled on top of finished food for added flavor and texture (and it just looks pretty). Don’t waste these salts on everyday seasoning; they have a heftier price tag, and you’ll lose the delicate flavor in the context of something like a pot of chili. Instead, use them to add a finishing touch on special meals—in other words, a small amount of these salts should last you awhile.
This umbrella term is where all of those fun flavors and colors come in, and some even have additives that change the flavor. Like fleur de sel and sel gris, these (usually expensive) salts aren’t used for cooking so much as they are used for finishing—sprinkled on a dish at the end for an added layer of flavor and texture. You’ve likely seen Himalayan Rock Salt—a pink salt, widely valued for its potential health benefits, that gets its rosy coloring from the naturally occurring iron and copper in the rock it’s harvested from. Other specialty salts include Black Salt, which is common in Indian cooking, and smoked salt, which is made either by adding liquid smoke or by smoking the salt over fire for long periods of time.