Kosher Salt vs. Sea Salt: How They Compare

A teaspoon of Morton kosher salt weighs 4.8 grams. A teaspoon of Diamond Crystal weighs 2.8 grams.¹ That spoonful, not the salt, is where recipes go wrong when you trade kosher salt for sea salt. Both are sodium chloride, and as America’s Test Kitchen (ATK) puts it, whatever the source, salt in its most basic form is the same.² What really differs is the crystal and the job each does best: kosher salt for seasoning, fine sea salt for everyday cooking, and coarse or flaky sea salt for finishing.

Side by side

	Kosher salt	Sea salt
What it is	Coarse-grained sodium chloride, named for koshering meat	Salt left behind when seawater evaporates
How it’s made	Both big US brands start from brine. Diamond Crystal: brine heated and stirred in open pans, forming hollow pyramid crystals. Morton: vacuum evaporators, then pressed flat between rollers¹	Varies by product. Morton’s fine and coarse sea salts are seawater evaporated by the sun³⁴
Grain	Coarse: hollow pyramids (Diamond Crystal) or thin flakes (Morton)	Fine, coarse or flaky, depending on the product
Additives	Morton: yellow prussiate of soda, an anticaking agent.⁵ Diamond Crystal: none, per ATK¹	Morton’s fine and coarse sea salts list sea salt as the only ingredient³⁴
Iodine	Not usually iodized⁶	Not usually iodized⁶
Sodium	About 40%, the AHA’s general figure for table, kosher and most sea salts.⁷ No laboratory analysis of either kosher brand found	38.9% to 40.7% in seven standard sea salts analyzed in Switzerland⁸
Grams per teaspoon	Morton 4.8 g; Diamond Crystal 2.8 g (ATK)¹	No measured figure found; Morton’s labels give 1.4 g per ¼ teaspoon for both its fine and coarse sea salt³⁴
Main job	Seasoning and cooking; ATK’s first choice for seasoning meat²	Fine: everyday cooking. Coarse and flaky: finishing
Flavor	Salty; Diamond Crystal crisp and light, Morton harder	Salty; fine sea salt behaves like table salt, coarse crystals crunch
Price	No dated, sourced comparison found	No dated, sourced comparison found

The sodium row puts a lab measurement of seven sea salts next to a general figure from the American Heart Association. They’re different kinds of number, and none of the Swiss samples was kosher salt.

How each is made

Kosher salt. You’ll sometimes see it called mined salt, but ATK says both major US brands are made from brine. Diamond Crystal uses the Alberger process: brine is heated and stirred in open containers, and hollow, pyramid-shaped crystals form on the surface. Morton pumps its brine into vacuum evaporators, then presses the salt through rollers into large, thin flakes.¹ The name comes from use. The coarse grains were used to draw blood out of meat, as Jewish dietary law requires. Morton says its kosher salt is kosher certified.⁵

Sea salt. It’s a broad category. Morton’s fine and coarse sea salts are both seawater evaporated by the sun, with nothing added.³⁴ Flaky sea salts and fleur de sel are made differently. See fleur de sel vs. sea salt for those. Sea salt is usually unprocessed or lightly processed.

Flavor: smaller differences than the labels suggest

ATK’s tasters found that sea salts vary in color but only slightly in flavor, and that sea salt tastes no different from table salt once it’s mixed into food.² In ATK’s kosher salt test, chicken broths seasoned with equal weights of Morton and Diamond Crystal tasted the same.¹

Two common explanations for flavor differences don’t hold up as stated:

“Neither has iodine, so neither tastes bitter.” Both are usually noniodized,⁶ but ATK’s tasters couldn’t taste any difference between iodized and noniodized salt.²
“Sea salt’s minerals give it a distinctive flavor.” The AHA says sea salt may carry trace minerals like magnesium, potassium and calcium.⁷ In the Swiss government survey, six of the seven standard sea salts had potassium below 0.05 g/kg, and the seventh had 1.2 g/kg, about 0.12% of its weight by our math. The survey concluded that specialty salts “do not possess any advantages over standard salts.”⁸

What does differ is texture: Diamond Crystal’s “delicate and fleeting crunch,” in ATK’s words, Morton’s harder flakes, and the crunch of coarse sea salt on a finished plate.¹

Measured: what the Swiss survey found in sea salt

The Federal Food Safety and Veterinary Office (FSVO) analyzed 25 salts bought from local retailers or online, including seven it classed as standard sea salts.⁸ Kosher salt wasn’t among them.

Measured (Swiss FSVO, 2016)	Seven standard sea salts
Sodium, %	38.9 to 40.7
Potassium, g/kg	Below 0.05 in six; 1.2 in one
Iodine, µg/kg	Below 20, or not detected, in four; 28, 44 and 54 in three

All figures come from the FSVO report’s Tables 1 and 2.⁸ For scale, US iodized salt has 45 micrograms of iodine per gram, or 45,000 µg/kg.⁶ By our math, the highest sea salt in the survey had roughly a thousandth of that.

Measuring: where the swap goes wrong

Most home recipes measure salt by the spoon, and a spoon holds very different weights of different salts.

Salt	Weight	Source
Morton kosher	4.8 g per teaspoon (ATK); 1.2 g per ¼ teaspoon (Morton label)	ATK¹; Morton⁵
Diamond Crystal kosher	2.8 g per teaspoon (ATK; rounded to 3 g in a later ATK article)	ATK¹⁹
Morton fine sea salt	1.4 g per ¼ teaspoon (label)	Morton³
Morton coarse sea salt	1.4 g per ¼ teaspoon (label)	Morton⁴
Flaky sea salts	No published figure found

ATK’s figures are its own weighings. Morton’s are label serving sizes, which are rounded. Compare like with like: the label figures with each other, ATK’s with each other.

Sea salt to Morton kosher, by volume: the figures disagree.

For 1 teaspoon of Morton sea salt (fine or coarse)	Morton kosher	Source
Morton’s conversion chart (Morton products only)	1¼ teaspoons	Morton¹⁰
Computed from Morton’s own label weights (1.4 g ÷ 1.2 g per ¼ teaspoon)	about 1⅙ teaspoons	Morton³⁵

The chart and the labels come from the same company and differ by about 7%. We’re showing both instead of picking one. In practice the gap is smaller than a pinch, so start with the lower amount and taste.

Sea salt to Diamond Crystal. Morton’s chart treats its fine sea salt as equal to table salt by volume,¹⁰ and ATK’s rule for table salt is 2 teaspoons of Diamond Crystal per teaspoon.² Chaining two sources like that gives you a direction, not a measured ratio. As a starting point, use about twice the volume of Diamond Crystal and taste.

The table salt conversions disagree too. The kosher salt page lays out ATK’s rule (1½ teaspoons Morton, 2 Diamond Crystal per teaspoon of table salt) against Morton’s chart (1¼ Morton) and the 1¼ that ATK’s own gram weights imply.²¹⁰¹ ATK itself recommends weighing salt.⁹

Can one stand in for the other?

Yes, as long as you account for the spoon. These follow our kosher salt substitute and sea salt substitute pages.

Swap	Starting amount	Treatment
Either, measured into a recipe by weight	The same weight	Computed
Morton kosher in place of 1 teaspoon fine or coarse sea salt	1⅙ to 1¼ teaspoons, then taste	Disputed (see above)
Diamond Crystal in place of 1 teaspoon fine sea salt	About 2 teaspoons, then taste	Method
Fine sea salt in place of 1 teaspoon Morton kosher	About ¾ teaspoon, then taste	Method
Fine sea salt in place of 1 teaspoon Diamond Crystal	About ½ teaspoon, then taste	Method
Kosher salt in place of flaky sea salt, for finishing	By the pinch, to taste	Method
Coarse sea salt in place of kosher salt, for seasoning meat before cooking	By the pinch, to taste	Method

How we worked these out. By weight: the Codex standard requires food-grade salt to be at least 97% sodium chloride on a dry basis,¹¹ and the Swiss sea salts measured close to pure sodium chloride,⁸ so a gram of either carries about the same salt. By volume: the kosher-to-sea-salt amounts reverse the figures above, rounded down so you start low.

Two bits of older advice need care. A teaspoon of fine sea salt does carry more salt than a teaspoon of kosher salt, but how much more depends on the brand. By our math on Morton’s own label weights it’s about 17% more than Morton kosher,³⁵ and it’s roughly twice as much as Diamond Crystal if you combine Morton’s chart with ATK’s rule, which is an estimate, not a measurement. And you’ll hear that fine crystals clump and make some bites saltier. We found no test of that.

Which to use when

ATK’s testers make kosher salt their first choice for seasoning meat, because the coarse grains are easy to pinch and spread.² Its grains dissolve more slowly than table salt’s, which Tufts notes can help season the surface of food.¹² Morton suggests its kosher salt for brining poultry and for grilled meats and vegetables.⁵

ATK recommends sea salts as finishing salts.² Morton pitches its coarse sea salt for crunch on vegetables, roasted potatoes, fruit and chocolate desserts, and its fine sea salt, which it calls quick-dissolving, for marinades, soups and dressings.⁴³ So “sea salt” isn’t one job. Fine sea salt does what table salt does, and coarse and flaky sea salts handle the finishing.

You’ll also hear that a sea salt’s mineral taste disappears in cooking, so you should save it for finishing. There’s no source behind that, and ATK found that sea salt tastes no different from table salt once mixed into food.² The reason to finish with sea salt is texture.

Colored sea salts

Some sea salts are sold for their color. Red Hawaiian (ʻalaea) salt is white salt mixed with red ʻalaea clay, and the color comes from iron oxide in the clay, not from the salt.¹³ See Hawaiian sea salt and alaea salt.

Health notes

Sodium. The AHA says table salt, kosher salt and most sea salts are about 40% sodium by weight. A coarse salt holds less sodium per teaspoon only because fewer crystals fit in the spoon.⁷ Choosing sea salt over kosher salt won’t lower your sodium.
Iodine. The NIH Office of Dietary Supplements lists both sea salt and kosher salt among specialty salts that usually aren’t iodized, and says noniodized sea salt provides virtually no iodine.⁶ If you cook only with these and rely on salt for iodine, see sea salt vs. iodized salt and iodized vs. non-iodized salt.

What isn’t known

We found no lab analysis of Morton or Diamond Crystal kosher salt. The Swiss survey didn’t include kosher salt.
We found no independent weighing of a teaspoon of fine, coarse or flaky sea salt, only Morton’s rounded label figures.
We found no published test of how differently the two dissolve or spread through food.
We found no dated, sourced price comparison.

Kosher salt and sea salt, the full profiles
Kosher salt substitutes and sea salt substitutes
Kosher salt vs. table salt, kosher salt vs. Himalayan salt and Maldon salt vs. kosher salt
Table salt vs. sea salt, fleur de sel vs. kosher salt and fleur de sel vs. sea salt
Cooking with kosher salt, cooking with sea salt and too much salt

Kate Shannon Levine, The Best Kosher Salt, America’s Test Kitchen, 2019. americastestkitchen.com · Publication ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰
Salt Types and Measurements, America’s Test Kitchen. americastestkitchen.com · Publication ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹
Morton Fine Sea Salt, product page, Morton Salt. mortonsalt.com · Merchant ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸
Morton Coarse Sea Salt, product page, Morton Salt. mortonsalt.com · Merchant ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶
Morton Kosher Salt Flakes, product page, Morton Salt. mortonsalt.com · Merchant ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶
Iodine: Fact Sheet for Health Professionals, NIH Office of Dietary Supplements. ods.od.nih.gov · Regulator ↩ ↩² ↩³ ↩⁴ ↩⁵
Sodium Sources: Where Does All That Sodium Come From?, American Heart Association, 2025. heart.org · Reference work ↩ ↩² ↩³
Esther Infanger and Max Haldimann, Report on the composition of prevalent salt varieties, Swiss Federal Food Safety and Veterinary Office, 2016. warwick.ac.uk · Regulator ↩ ↩² ↩³ ↩⁴ ↩⁵
Eden Faithfull, The Wrong Brand of Kosher Salt Could Ruin Your Dinner, America’s Test Kitchen, 2022. americastestkitchen.com · Publication ↩ ↩²
Salt Conversion Chart, Morton Salt. mortonsalt.com · Merchant ↩ ↩² ↩³
Standard for Food Grade Salt, CXS 150-1985 (rev. 2012), Codex Alimentarius. services.bis.gov.in · Standard ↩
What’s the difference between kosher salt and other salt?, Tufts Health & Nutrition Letter, 2013 (updated 2019). nutritionletter.tufts.edu · Publication ↩
Traditional Ways of Knowing: Salt Harvesting, University of Hawaiʻi at Mānoa, 2011. manoa.hawaii.edu · Reference work ↩

Kosher Salt vs. Sea Salt: Same Chemistry, Different Crystals and Spoon Weights