Sea Salt: What It Is, How It’s Made, and How It Compares to Table Salt

Sea salt is the salt left behind when seawater evaporates, but chemically it’s the same sodium chloride as any other cooking salt, and most sea salts carry about the same 40% sodium as table salt.¹ In America’s Test Kitchen’s testing, sea salt mixed into food tasted no different from table salt. Where it does change a dish is on the surface, as big flakes that stay crunchy. And like other specialty salts, it usually isn’t iodized.

At a glance

What sea salt is

Every food-grade salt, wherever it comes from, has to be mostly sodium chloride. The Codex Alimentarius standard for food-grade salt covers salt from the sea, from underground rock salt deposits and from natural brine, and sets the sodium chloride content at no less than 97% of the dry matter, not counting additives.⁴ Salt is sodium chloride whatever its source, and the types differ in texture, shape and mineral content.

Sea salt is usually unprocessed or lightly processed. Table salt is mined from deposits and processed to a fine texture, which strips out other minerals. Morton says its fine sea salt is made from sea water “evaporated by the sun” and calls solar evaporation the oldest way of making salt, a claim we couldn’t check against an independent source.³

Solar salt is a small slice of the salt business. In the United States in 2024, solar salt was about 9% of salt sold or used, against 42% salt in brine, 40% rock salt and 9% vacuum pan salt. Highway deicing alone took about 41% of the salt consumed.⁵

Flavor and texture

In America’s Test Kitchen’s testing, sea salt’s flakes varied in color but only slightly in flavor, and once mixed into food it tasted no different from table salt.⁶ ATK’s takeaway: shop for texture, not origin. You’ll often read that sea salt tastes “stronger” than table salt, so you can use less. We found no test that backs this up, and ATK’s results point the other way.

Where sea salt does change a dish is on the surface. Big flakes sprinkled on at the end stay crunchy and visible, while fine sea salt dissolves just like table salt. That’s why ATK recommends sea salt mainly as a finishing salt.⁶

Minerals and color

Sea salt may carry trace levels of minerals such as magnesium, potassium and calcium. The AHA’s point is that these are trace amounts, you get the same minerals from other foods, and for heart health your total sodium is what counts most.¹ We didn’t find any published analysis showing that darker sea salts carry meaningfully more minerals, so we don’t claim it.

When a sea salt has color, there’s often a specific physical reason. The French specification for Guérande salt is a well-documented case. Its gray salt is gray from clay particles picked up off the pan floor, while its fleur de sel is white and sometimes faintly pink from the alga Dunaliella salina.⁷ That explains those two salts only. Other colored salts need their own evidence.

Origin and history

People have made salt from seawater in lots of places, but the history you can document is local. For Guérande, on France’s Atlantic coast, the earliest written mention of salt pans is in the Cartulary of Redon, dated 15 December 854. The pans spread from the 16th century, peaked in the 19th, and production fell off between 1840 and 1960.⁷

Two older claims get repeated a lot: that Buddhist scriptures of the 5th century BCE mention sea salt production, and that Romans finished their brine in clay pans over peat fires. We couldn’t trace either to a source, so we’re leaving them out.

How sea salt is used

Fine sea salt works anywhere table salt does. Coarse crystals and flakes are mostly finishing salts: on sliced steak, roasted vegetables, salads, bread crusts, caramel and chocolate. ATK’s testers found no noticeable benefit to cooking with sea salt over table salt and save it for finishing, where you can feel the crunch.⁶ For recipes and techniques, see cooking with sea salt; for flavored versions, see smoked sea salt.

Measuring sea salt

Different crystal sizes put different amounts of salt in a spoon. For its own products, Morton’s chart treats 1 teaspoon of table salt as equal to 1 teaspoon of its coarse or fine sea salt, with small additions only at bigger volumes (1 cup of table salt equals 1 cup plus 1 teaspoon of its fine sea salt). Morton says the chart applies when you’re swapping one Morton product for another.⁸ We found no published conversion for flaky sea salts, which vary too much from brand to brand for one number to mean much. When a recipe just says “sea salt,” start with less and taste.

Buying and quality

Pick the texture first. Fine sea salt is for cooking and baking, coarse crystals for grinders and crusts, flakes for finishing. Origin labels mostly matter where a protected designation sets rules. Under the Guérande specification, for example, the salt is harvested by hand, isn’t washed after harvest, and can’t contain additives; gray salt can hold up to 12% moisture.⁷ For specific salts, see Celtic sea salt, Maldon sea salt, fleur de sel, Hawaiian sea salt and Anglesey sea salt.

Storage

We found no shelf-life figure for sea salt from a regulator or standards body. Moist, unwashed salts can clump, so keep the container closed and dry.

Safety and health

Sodium

Sea salt isn’t a low-sodium salt. Table salt, kosher salt and most sea salts are about 40% sodium. A teaspoon of coarse sea salt can hold less sodium than a teaspoon of table salt only because fewer big crystals fit in the spoon, and the AHA suggests checking the Nutrition Facts label.¹ The FDA’s Daily Value for sodium is less than 2,300 mg a day, which it puts at about a teaspoon of table salt.⁹ The WHO recommends adults keep sodium below 2,000 mg a day (under 5 g of salt) and names raised blood pressure as the main health effect of eating too much sodium.¹⁰

Iodine

Most sea salt isn’t iodized. The NIH Office of Dietary Supplements says specialty salts such as sea salt, kosher salt, Himalayan salt and fleur de sel usually aren’t, and that noniodized sea salt provides virtually no iodine.² Morton’s fine sea salt, for example, lists sea salt as its only ingredient.³ If you rely on salt for iodine, use iodized salt; see sea salt vs. iodized salt and iodized vs. non-iodized salt.

Microplastics

A 2018 study by Ji-Su Kim and colleagues in Environmental Science & Technology tested 39 salt brands from 21 countries and regions and found microplastics in 36 of them.¹¹ The sample was 28 sea salts, 9 rock salts and 2 lake salts, and contamination was highest in sea salt, then lake salt, then rock salt. The average across all samples was 506 particles per kilogram. These figures come from a Greenpeace press release on the study, since we couldn’t open the paper itself. They describe 39 products bought for one study, not the sea salt market as a whole.

Substitutes and comparisons

Any salt can stand in for sea salt by weight. By volume, crystal size decides the swap. See sea salt substitutes for options, and these comparisons:

• Table salt vs. sea salt
• Kosher salt vs. sea salt
• Himalayan salt vs. sea salt
• Fleur de sel vs. sea salt
• Rock salt vs. sea salt
• Pickling salt vs. sea salt

Overdid it? See too much sea salt. For choosing between salts, see the best salt for cooking.