Sun-evaporated salt vs kettle-boiled salt: the world of making salt without fire

Turn over the bags of salt on a supermarket shelf and you find words like "sun-evaporated," "flat pan," "sengo." All of it is sea salt, and yet it is made in very different ways.

The biggest split is between salt dried by sun and wind and salt reduced over fire. Once you know that difference, how you choose a salt shifts a little.

Boil the salt, or dry it

Getting salt out of seawater means driving the water off and leaving the crystals behind. There are two roads to driving that water off.

One is to heat and reduce it in a flat pan or a similar vessel. Crystals come out quickly and consistently, and the grains take an even shape. There are many salts finished carefully this way, such as those made by the agehama process of Noto.

The other is to use no fire at all and dry the water off with sun and wind alone. It takes time, but because no heat is applied, the edges of the minerals in the salt are said to stay softer.

Fully sun-evaporated: no fire at any point

Among salts that use the sun, those made with no fire at all from concentration through crystallization are called fully sun-evaporated salt.

Seawater is spread in a greenhouse or a salt field, left to sun and wind so it thickens little by little, and then you wait for crystals to grow on the bottom. Depending on the weather, taking months to finish is nothing unusual. The makers stir the seawater every day and watch how the crystals come along. Not boiling the salt but growing it. That is how the work gets described.

In return for not being hurried, the yield is tiny. That it is hard to get hold of follows directly from the method.

Tosa no Umi no Tenpijio Amami: handwork from Kuroshio Town

The maker holding to this fully sun-evaporated method is "Tosa no Amamiya" in Kuroshio Town, Kochi Prefecture. On the shore of Tosa Bay, where the Kuroshio current first strikes land, they go on making salt without any fire.

Seawater is spread in crystallizing boxes inside a greenhouse and left to sun and wind for months. Salt grown by hand, stirred every day with a wooden pole, lives up to its name: taste it and a faint sweetness spreads out behind the saltiness. A treasure of Tosa with the gift of the sun sealed in as it is.

How to enjoy sun-evaporated salt

• Start with a salted rice ball. You can taste the sweetness of the rice and the sweetness of the salt stacking up
• A pinch on raw vegetables such as tomato or cucumber
• Sprinkled on grilled fish, or served as dipping salt with tempura
• Rubbed into meat. Coarser grains also work as a final sprinkle at the finish

The same sea salt can wear this many faces depending on how it is made. Swap your usual salt once, and the simpler the dish, the more plainly the difference shows.

Frequently asked questions

What is the difference between sun-evaporated salt and kettle-boiled salt?

The big difference is whether fire is used to crystallize the seawater. Sun-evaporated salt relies on sun and wind alone, taking months to drive the water off. Kettle-boiled salt is heated and reduced in a flat pan or similar vessel. Generally, sun-evaporated salt is said to keep its minerals gently and to taste mellow, without hard edges.

What is fully sun-evaporated salt?

Salt made without any fire at all at any stage, from concentrating the seawater through growing the crystals. With only sun and wind to work with, it is at the mercy of the weather and can take months to finish. Because it takes so much work and yields so little, it is treated as a scarce salt.

What dishes suit sun-evaporated salt?

The taste of the salt itself comes through easily, so it is best to start with simple dishes that let ingredients speak: salted rice balls, raw vegetables, grilled fish. Even used as a pinch at the finish, the difference in taste is easy to pick up.