Refined salt vs "natural" salt: the salt that keeps its nigari, and the salt that strips it

Turn a bag of salt over and you find words lined up on the back: "ion membrane," "flat pan," "sun-evaporated," "100% seawater." Prices range just as widely, from a little over 100 yen for 1kg to more than a thousand yen for 100g.

All of it is salt. So why the gap? The dividing line is a single point: whether the nigari is kept or taken out.

Why a salt that is 99% sodium chloride came to exist

Sodium chloride is not the only thing dissolved in seawater. Magnesium, calcium and potassium are in there with it, and together they are called nigari. It is the same stuff that sets tofu.

Japan made its salt in coastal salt fields for a long time, but the salt industry modernization of 1971 (Showa 46) wiped those fields off the map. What took over was a method that pulls the salt out of seawater efficiently with an ion-exchange membrane. Sodium chloride purity runs high with it, and salt refined to 99% or above can be produced in bulk, consistently.

It keeps well, the grains are even, and it is cheap. An easy salt to handle for industry and for the home kitchen alike. Almost none of the nigari survives, though. The saltiness rises straight and strong, and the outline of the taste in a finished dish is sharply drawn.

When the nigari stays, the shape of the taste changes

Salt that keeps its nigari makes a different impression on the tongue. Behind the saltiness sit a faint bitterness, a sweetness, and a certain thickness. That is the part people describe as mellow, or as having no hard edge.

The gap opens up less in dishes you merely sprinkle and more in dishes that use a lot of salt. Where salt spreads through the whole pot, simmered dishes, soups, pasta water, the difference in how the saltiness rises carries straight through to the finished dish.

One note. Salts like these are widely spoken of as shizenshio or tennenshio, natural salt, but the fair competition code on labelling edible salt does not accept those words as product labelling. That is why real packaging says "100% seawater," "flat pan," "sun-evaporated" instead. When you choose a salt, reading that method line beats reading words that only convey an image.

Hon-Nigari Jitate Gotonada no Shio: an island salt for every day

Sakito, Saikai City, Nagasaki Prefecture. On a small island ringed by the Gotonada (五島灘), the stretch of sea that opens onto the East China Sea, they make "Gotonada no Shio." This is also land that once thrived on salt-making.

The salt uses 100% seawater and is finished with the nigari left in. Magnesium and other minerals stay dissolved in it, giving a deep taste with no hard salty edge.

The other thing to note is the price. A 750g bag is priced so that you need not hold back, so you can use it freely for pasta water and for simmered dishes alike. Not "good salt for special days" but "good salt every day." Because this is a salt whose difference shows precisely in dishes that use a lot of it, that position means something.

As a maker that held on to the older way of making salt, "Umi no Sei Arashio" from Izu Oshima is the other bottle to know, the starting point of the story. After the salt fields vanished in 1971, this is the maker that kept producing in order to keep the craft of sea salt alive.

How to use a salt that keeps its nigari

• Swap it in for the salt in simmered dishes and soups. The more you use, the more it shows
• Use it in the water for pasta or leafy greens. The base of the taste changes from the seasoning stage on
• Use it for salted rice balls. The sweetness of the rice and the sweetness of the salt stack up
• Sprinkle it on grilled fish, or season meat with it
• Use it for pickling plums and vegetables. In preserves where salt is the lead, the difference stays

None of this makes refined salt a bad salt. It has a different job. Still, swap the one bag you cook with every day and you notice the taste move without a single change to the recipe.

Frequently asked questions

What is the difference between refined salt and natural salt?

The biggest difference is whether the nigari components (magnesium, calcium, potassium and so on) are left in. Refined salt raises the purity of sodium chloride by methods such as the ion-exchange membrane, reaching 99% or higher. Salt made from seawater keeps some of its nigari, so behind the saltiness you are more likely to notice bitterness, sweetness and body.

Can labels say "shizenshio" or "tennenshio," natural salt?

Not on product packaging. The fair competition code on labelling edible salt does not permit "natural salt" or "naturally occurring salt," so actual products carry method and ingredient wording instead: "100% seawater," "flat pan," "sun-evaporated." When you are choosing a salt, reading that method line is the reliable move.

What dishes suit a salt that keeps its nigari?

The more salt a dish uses, the more the difference shows. Try it where salt spreads through everything: simmered dishes, soups, the water you boil pasta in. Even in dishes where salt is the lead, such as rice balls or grilled fish, the way the saltiness rises changes.