Most sea salt is unrefined. It’s produced by evaporating seawater and collecting the crystals left behind, a process that involves minimal mechanical or chemical processing. That said, some brands do refine their sea salt, so the label on the package matters more than the category itself.
What Makes Salt “Refined” or “Unrefined”
The difference comes down to what happens after the salt is harvested. Unrefined salt is collected, sometimes washed lightly, and sold with its natural mineral content intact. Refined salt goes through additional steps: it’s treated with a chlorine-based solution to strip away impurities, which also removes most of the trace minerals naturally present. After that, iodine is typically added back in (to prevent deficiency), along with an anti-caking agent like sodium aluminosilicate to keep the grains from clumping.
Standard table salt is the most common example of a fully refined product. It starts as either mined rock salt or sea salt, but by the time it reaches your shaker, it’s been processed into nearly pure sodium chloride, with a uniform white color and fine, free-flowing texture. Sea salt that’s sold as unrefined skips most of those steps, which is why it looks and tastes different.
How to Tell if Your Sea Salt Is Unrefined
Unrefined sea salt has a few visual giveaways. The crystals tend to be coarser and less uniform than table salt. You might notice a slight off-white, gray, or even pinkish color, all of which come from trace minerals absorbed from the water and clay where the salt was harvested. Celtic sea salt from Brittany, France, for example, has a distinctive gray hue (it’s sometimes called “sel gris,” meaning “gray salt”). A bit of moisture in the crystals is also normal and actually indicates the minerals haven’t been stripped out.
If your sea salt is perfectly white, very fine, and pours without clumping, it has likely been refined to some degree. Check the ingredient list: if you see anti-caking agents or added iodine, the salt has been processed beyond simple evaporation.
The Mineral Difference
Unrefined sea salt retains small amounts of minerals like magnesium, potassium, and calcium that are naturally present in seawater. These give unrefined varieties their slightly more complex flavor compared to table salt. The actual quantities, though, are small. Salt is still about 95 to 98 percent sodium chloride regardless of how it’s processed, and you’d need to eat far more than a healthy amount of salt to get meaningful doses of those trace minerals from it alone.
Where the mineral content matters most is in cooking. Many chefs prefer unrefined sea salt because those trace minerals contribute subtle flavor differences, particularly as a finishing salt where you can taste it directly.
Microplastics and Contaminants
Because unrefined sea salt comes directly from ocean water with minimal processing, it does carry whatever is in that water. Research published in Environmental Science and Pollution Research found roughly 30 microplastic particles per kilogram in coarse sea salt samples. That’s a tiny amount, and interestingly, it was lower than what researchers found in some land-sourced salts like Himalayan pink salt and black salt, which contained over 150 particles per kilogram.
At typical salt intake levels (a few grams per day), the microplastic exposure from sea salt is very small compared to other dietary sources like drinking water and seafood. Refining does remove some of these particles, so fully processed table salt tends to have fewer contaminants of this kind, though no salt is completely free of them.
No Official Definition of “Unrefined”
There is no regulated legal definition for the term “unrefined” on salt packaging in the United States. The FDA sets labeling rules for food products, but it hasn’t established specific criteria that salt must meet to be called unrefined. This means the term is largely used at the manufacturer’s discretion. A salt labeled “unrefined” from one brand might undergo slightly different handling than one from another brand.
Your best bet is to look at the ingredient list rather than relying on front-of-package marketing. Truly unrefined sea salt will list only one ingredient: sea salt. If you see additives, it’s been processed further, regardless of what the label claims. Color and texture are your secondary clues: the more it looks like something scooped from a tidal flat and the less it looks like table salt, the less processing it has undergone.