What Is Celtic Sea Salt? Grey Salt, Minerals and How It Compares

What is Celtic salt?

"Celtic Sea Salt" started as a brand name. The company was founded in 1976 by Jacques Delangre in California, under the name Grain and Salt Society, to import hand-harvested salt from the Brittany region of France. The business later moved to North Carolina, and his daughter-in-law, Selina Delangre, renamed it Selina Naturally in 2007 (Celtic Sea Salt; WNC Magazine).

Today many shoppers and recipes use "Celtic salt" loosely for any moist, grey, unrefined sea salt from the Atlantic coast. The traditional French name for that salt is sel gris, which simply means grey salt. Well-known sources include Guérande, Île de Ré and Noirmoutier.

How unrefined grey sea salt (sel gris) is made

Seawater is let into a series of shallow ponds, where sun and wind slowly evaporate it. As salt crystals form, salt workers (paludiers in French) rake them up with long wooden tools. Because sel gris touches the bottom of the pond before it is raked, it picks up a little of the clay or mud lining, which is where its grey color comes from.

The salt is not dried or refined, so it stays damp. Sel gris typically holds around 13% residual moisture (Bitterman, Salted, 2010). That is why it feels wet and clumps in a shaker.

Fleur de sel, the finer sibling, is a fragile film of crystals floating on top of the same ponds. Workers skim it by hand, and only in settled, sunny, dry spells with a light breeze, so yields are small and it is the priciest salt of the bunch.

Is Celtic salt healthier? Minerals and sodium

Unrefined sea salt does carry trace minerals. A certificate of analysis for a Breton sel gris sold by the US importer SaltWorks lists about 4,470 parts per million of magnesium, 1,320 of calcium and 1,180 of potassium. In plain terms, a quarter teaspoon (about 1.5 g) would supply roughly 7 mg of magnesium. Adults need about 310 to 420 mg a day (NIH Office of Dietary Supplements), so that is around 2% of a day's need.

The same pattern holds for pink salt: researchers testing 31 pink salts found you would need more than 30 g a day, about 6 teaspoons, to get a meaningful amount of any nutrient, which would bring dangerous amounts of sodium (Fayet-Moore et al., Foods, 2020).

Sodium is the part that counts. The American Heart Association notes that table salt, kosher salt and most sea salts are all about 40% sodium by weight. Moist salts can be slightly lower per spoonful because some of the weight is water: the Celtic Sea Salt brand's Light Grey Celtic label lists 480 mg of sodium per quarter teaspoon (1.5 g). The general limit for adults is 2,300 mg of sodium a day, and 1,500 mg for people on low-sodium diets (Cleveland Clinic).

Does Celtic salt have iodine?

Not in any useful amount. According to the NIH Office of Dietary Supplements, iodine is rarely added to gourmet and specialty salts, grey sea salt included, and unfortified sea salt contains next to none. A quarter teaspoon of iodized table salt, by comparison, provides about 78 mcg.

Adults need 150 mcg of iodine a day, rising to 220 mcg in pregnancy and 290 mcg while breastfeeding (NIH ODS). Packaged foods won't fill the gap, since US food makers almost never use iodized salt. If grey salt is your only salt, make sure iodine comes from somewhere else, such as dairy, eggs, seafood or seaweed. Only about half of US prenatal vitamins contain iodine, so check the label if you are pregnant (NIH ODS).

Celtic salt vs table, Himalayan, kosher and fleur de sel

Crystal size varies, so a teaspoon of one salt can hold far more salt than another. When switching salts, go by taste or weight.

How to cook with grey sea salt

• Pinch, don't shake. Damp crystals clump, so keep coarse grey salt in a small bowl or salt cellar.
• Crush or dissolve. Crush coarse crystals between your fingers or in a mortar, or let them dissolve in pasta water, soups and sauces.
• Use fine grey salt for baking and dressings, where coarse crystals would not dissolve evenly.
• Finish with it. A few crystals on roasted vegetables, eggs or fish add crunch.

Sole water and adrenal cocktails

Grey and pink salts are often promoted in two wellness trends. Sole water is salt left to dissolve in water overnight, then sipped by the teaspoon in a glass of water. Cleveland Clinic says its claimed benefits for energy, sleep, cramps and detox do not stand up to scrutiny, since the minerals are only trace amounts and the main thing it adds is sodium.

An adrenal cocktail is usually orange juice or coconut water with a pinch of sea salt, sometimes with cream of tartar. Cleveland Clinic reports no evidence that it improves adrenal function, lowers cortisol or raises energy. "Adrenal fatigue" itself is not a recognized diagnosis: a systematic review of 58 studies found no substantiation that it exists (Cadegiani and Kater, BMC Endocrine Disorders, 2016). People with kidney disease should avoid the potassium-heavy version unless their doctor approves it.

Find it at William's

We don't currently list the Celtic Sea Salt brand online; call the store to check what's on the shelf. We do carry the same style of salt: French grey sea salt (sel gris), fine, from Starwest, sold by weight in our bulk section.

For comparison or for your grinder, we also stock coarse sea salt and Himalayan pink salt, coarse, both by weight. Read how mined salts differ in our rock salt guide, or pair your salt with ideas from our umami seasoning and Kerala spices guides.

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