What’s With All the Different Salts? Here’s How to Use Them.

Knee-deep in the improbably pink marsh water of the Camargue, on the southern coast of France, I shoveled fleur de sel crystals onto the shore into shimmering mounds, the same way that the sauniers, traditional salt workers, toiling around me on a hot July morning have been doing in that region since Roman times.

Eric Beaumer, a master saunier at Le Saunier de Camargue, sprinkled some of the warm, damp salt into my hand. I licked my palm and the shards crunched, then dissolved in a saline burst. It was the same mineral rush I had experienced earlier that day when I sprinkled fleur de sel on my eggs, and the one I would have again two hours later with a tomato salad. The brittle crystals made the eggs seem more custardy, the tomatoes more ripely sweet. That’s the magic of flaky sea salt: It makes food taste more deeply of itself.

Legions of chefs and home cooks have fallen hard for fancy, flaky salt — even though it can cost more than 10 times as much as the stuff you’d find in a shaker. But 30 years ago, here in the Camargue, only a few devoted sauniers bothered to harvest fleur de sel at all.

Recipe: Salt-Baked Fish

“We couldn’t give it away,” Mr. Beaumer said, handing me another pinch to crunch.

This is because, for most of the 20th century, salt was just salt, and largely industrial table salt — tiny white grains of near-pure sodium, the saline version of factory-sliced white bread — at that. Cheap and modern, it wore its sterile absence of color and variability as a badge of purity.

But decades before Salt Bae, and around the same time as the rise of the organic food movement, chefs started to rediscover salts with character: snowflake-like Maldon, minerally fleur de sel, Himalayan salt with its sunrise glow.

Innovators like Ferran Adrià at El Bulli, Alice Waters at Chez Panisse and Ruth Rogers of the River Café found that flaky salt made a vast difference in their cooking. Just a few grains sprinkled on at the end could transform anything — pastas, roasted meats, soups, chocolate desserts — in a way that granular salt simply couldn’t.

Cookbook and recipe writers began calling for different varieties — sometimes, maddeningly, in the same recipe. A growing subset of hard-core salt-tooths carry rarefied crystals in tins the size of a thumb, at the ready in a pocket or purse to calibrate any restaurant dish to their own personal ideal of salinity.

Today, these select salts are easier to find than ever before, both in supermarkets and online. But being this spoiled by choice can be confusing. Are fine sea salt and table salt interchangeable? Can you finish a dish that calls for flaky Maldon with coarse sea salt from a grinder instead? And why do various brands of kosher salt — Morton’s and Diamond Crystal, for example — have such different levels of salinity?

To help break it all down, here’s a salt primer.

A Brief History of Salt

To really understand salt, a bit of background helps. Its production has been at the center of human culture for thousands of years. Biologically, of course, we cannot exist without salt. Sodium chloride regulates our bodily fluids and is essential for nerve, muscle and digestive function. (Fittingly, the word salubrious derives from the Latin root sal, which means salt.)

Early humans got all the salt they needed from eating animal flesh; there’s very little salt naturally present in plants.

No one knows exactly when or how people figured out methods to produce salt — from evaporating seawater or mining rock salt from the earth — but it most likely happened with the rise of agriculture and animal husbandry in the Neolithic period. As humans increased their dependence on vegetables and grains, they had to start salting their food.

And, as early civilizations developed, salt became one of their primary economic drivers, said Mark Kurlansky, the author of “Salt: A World History.” “Before the Industrial Revolution, most international trade was of food,” he said, “and you couldn’t trade food without preserving it in salt first.” Fish, meat, vegetables and cheeses were all heavily salted (and sometimes fermented) before being shipped around the globe. And in ancient Egypt, Mr. Kurlansky said, people weren’t just using salt to preserve their food; they used it to preserve their dead.

“A mummy is a salted product, just like a codfish,” he said.

Until its mass production in the early 20th century, salt was necessarily expressive of the geography and climate where it was produced. The mineral content of the salt, evaporation or mining techniques used to harvest it, and local traditions produced wildly different results, from blood-red Haleakala crystals from Hawaii, to nubby gray pebbles from Brittany and glassy white Hana flakes from Japan — all of which are still produced, at least in small quantities.

Mark Bitterman, the author of four books on salt and an owner of the Meadow, a small chain of specialty salt shops, calls pre-industrial salt the first local food, a totem of place and time.

“Most salt has no place. It’s an industrialized product and can come from anywhere,” he said of modern varieties. But a traditionally made salt connects us to its origin in a vital, immutable way. “You can grow a San Marzano tomato in California, but you can’t make fleur de sel de Guérande in San Francisco Bay.”

Location isn’t the only factor; technique is also pivotal.

Ben Jacobsen, the owner of Jacobsen Salt Co. in Portland, Ore., had his come-to-salt moment over an arugula-and-tuna salad, awed by the way the feathery crystals added a crunch that went beyond saltiness. “It was just arugula, canned fish and olive oil, but the salt made everything so much better,” he said. “It blew me away.”

Mr. Jacobsen’s impulse was to make his own. His first attempt was in his home kitchen, using a stockpot and water he’d lugged home from Netarts Bay, on a kayaking trip down the Oregon coast.

It took a day and a half for the liquid to boil away, evaporated salt stubbornly crusting every surface of his kitchen. But finally, in the bottom of the pot was a layer of moist, coarse, sandy salt.

“I was really proud of myself,” he said, “until I tasted it.” It was acrid, bitter and gravelly, not at all like the light Maldon flakes he was trying to emulate. It took him two years to work out how to produce the giant flakes of crystalline pyramid salt he was looking for.

“Anyone can make salt — it’s not difficult,” he said. “But making great salt, consistently? That’s a whole other thing.”

What to Use When

Salt comes in a dizzying array of different kinds. Here’s a guide to understanding some of the most popular salts and strategies for using them.

Table Salt

Ubiquitous and cheap, table salt is found in saltshakers all over the world. Most is made by pumping water into salt mines to dissolve the minerals, then evaporating the water under a vacuum and separating out the sodium chloride.

The tiny, fine crystals are uniform in size and color. Table salt is iodized to help protect against iodine deficiencies, and this necessitates the addition of chemicals, such as dextrose or sodium bicarbonate for stability. To keep the salt from absorbing moisture from the air and clumping, anticaking agents like calcium silicate and sodium ferrocyanide (yellow prussiate of soda) may also be added.

Table salt dissolves quickly when sprinkled on food or during cooking, and can taste harsh and slightly metallic, as well as stridently salty. But you can use it as an all-around cooking salt, and it’s interchangeable with fine sea salt.

Kosher Salt

Kosher salt does not necessarily mean salt that has been blessed by a rabbi. Pure salt, an inert mineral, doesn’t need rabbinical certification to be used in kosher homes (though some brands are certified to guarantee that nothing else got mixed into the box).

What defines kosher salt is its large, coarse grains. The term is a shortening of koshering or kashering salt, because its traditional use is to remove the blood from meat, as required by Jewish dietary laws. The large salt crystals draw out blood without dissolving much, which keeps the meat from becoming oversalted. And the coarse grain is perfect for making a salt crust, a traditional method for cooking whole fish that results in especially tender, juicy flesh.

Like table salt, most kosher salt is industrially produced. It isn’t iodized, but might contain anticaking agents, which will be listed on the label. The two dominant brands on the market, Morton’s and Diamond Crystal, are manufactured using different processes, which makes them extremely dissimilar. Morton’s has dense, heavy cubes that pack together tightly in a measuring spoon. Diamond Crystal, the darling of professional chefs, is shaped into light flakes that remain somewhat separate.

When measured by volume (teaspoons, tablespoons, pinches), Morton’s is twice as salty as Diamond Crystal (see this chart for more salt comparisons). Substituting one for the other can wreak havoc on your recipe, rendering a dish too salty or not salty enough. Weighing solves this problem, because all salts can be used interchangeably by weight.

Common Sea Salt

Most inexpensive sea salt is industrially produced from seawater. It can be processed into fine granules like table salt, or coarser cubes to be either used in a salt grinder or added directly to pasta water, soups and stews. Sea salt is sometimes coated with anticaking agents, but, since it doesn’t usually contain iodine, it can have a cleaner flavor than table salt. Fine sea salt is often used in baking because of its ability to dissolve quickly, and can be used in place of table salt in cooking.

Traditional Sea Salts

Built on age-old traditions, sea salts like fleur de sel, sel gris and flaky salt are all made by evaporating seawater, either in the sun in warm climates, or by boiling. They can have a variety of trace minerals that add character, color and texture. But because they’re usually expensive and don’t have a uniform crystal size or salinity, they’re not often called for in recipe ingredient lists. Used as finishing salt, traditional sea salts can bring plenty of textures and flavors to the table.

Sea Salt Flakes

All salt molecules form in cube-shaped crystals, and the faster they form, the smaller they are. Flake salt is made by encouraging salt crystals to form slowly on the surface of the brine, so they can get especially large. As they grow, their centers sink, creating pyramids that eventually fall to the bottom of the salt pan. At Maldon Salt in Essex, England, I raked up translucent pyramids as large as my palm, which fractured into thin, wide brittle flakes as I transferred them to their drying bins. Every once in a while you’ll find an intact salt pyramid in a box of Maldon, a delightful surprise.

Flake salt adds a gentle snap and bright saltiness to dishes. Because the flakes are so thin, you can add a fairly large pinch to dishes without oversalting, and this produces a crackly texture that dissipates quickly. Flake salts tend to have less minerality than other traditional sea salts, and their clean flavor makes them extremely versatile. Although Maldon is one of the best-known, other varieties include Jacobsen, Hana flake, Halen Mon and Marlborough flaky sea salt.

Fleur de Sel

Fleur de sel, also called flor de sal, translates to “the flower of salt,” a nod to its desirability. A product of warm, sunny climates, it’s been made in the same way for ages. Briny water is captured in shallow salt pans (often carved into marshland) and left to be evaporated by the sun and wind. Salt crystals form on the surface of the brine, and are then raked up by hand during harvest.

Fleur de sel is not refined, so it contains whatever minerals are present in the water. These minerals give the crystals a pleasingly lacy, irregular shape and distinctly oceanlike flavor that can have both sweet and bitter notes. Fleur de sel contains more moisture than most other salt varieties, so it doesn’t dissolve right away on the tongue; its saltiness lingers.

You can use fleur de sel to finish any dish where you want a crunch that’s softer and more crumbly than flake salt, with a more complex flavor. It works particularly well with desserts, especially those that include caramel and chocolate.

Sel Gris

Sel gris, gray salt, is produced in the same types of solar- and wind-evaporating salt pans as fleur de sel, but is harvested from the clay bottom rather than the surface. Meeting the clay is what gives sel gris its distinctive color. Sel gris is chunkier and pebble-like, with a distinct crunch that’s firmer and more pronounced than fleur de sel. Its mineral flavor is deeper, too, making it the most boldly flavored of all the sea salts. It shines when sprinkled on roasted meats, fish and vegetables, but might be too earthy-tasting for desserts.

Himalayan Pink Salt

People have long mined salt deposits, including from the Potwar Plateau in Pakistan, the source of Himalayan pink salt. It gets its blush from trace minerals, which also give it a mildly spicy flavor. Because its texture is quite firm, it’s often sold in grinders. It’s a pretty and crisp-textured finishing salt for boldly flavored dishes.

You’ll also see it made into cooking slabs, which can be heated to 900 degrees. Mr. Bitterman, the author, recommends heating slabs of Himalayan pink salt on the grill and using them for pizza, or to weigh down chicken instead of a brick.

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