The 300-Year-Old Sea Salt Making Tradition of Utazu

Utazu’s salt is produced through a long-held method that utilizes the gorgeous waters of the Seto Inland Sea and Kagawa’s abundant wind and sunlight. What sets it apart is the calcium and potassium contained in the seawater, which create a smooth and full-bodied flavor. Just a pinch in any dish reveals a gentle and rounded deliciousness without any of the sharp or bitter flavor one expects from table salt. There’s simply nothing like freshly-made, natural Utazu salt. 

Seawater is only 3% sodium—in other words, a single liter of seawater contains only about 30 grams of salt. This means that boiling off seawater as-is to extract salt is far too inefficient. Japan’s salt makers thus faced a huge challenge in figuring out how to extract salt from seawater using as little energy as possible. The answer was to first create a saltwater concentrate, from which salt crystals could be extracted through boiling. 

The sand is raked with a tool called a maguwa. This creates horizontal, vertical, and diagonal scoring which helps salt adhere to the sand. 

Seawater is poured over the scoring so that salt will adhere to the sand. Workers use a roughly 2 meter long tool called a hamakai-shaku to evenly distribute the seawater, spraying it over the sand in an arc. Seeing a master salt maker skillfully flinging seawater over the sand beds is a sight to behold. They repeat this process each time the sand has dried (roughly two to four times per day). After three or four days, enough salt will have adhered to the sand. Any rainfall before that means workers must start the process over, since rain reduces the sodium concentration of the fields. 

Buckets known as ninai oke are used to pour further seawater into the nui water filtration pen. This dissolves the salt stuck to the sand and raises the salinity of the mixture. Workers may transport up to 900 liters using these over-the-shoulder buckets. This weight is akin to lifting the roof of a house, requiring workers to have plenty of stamina. 

The seawater concentrate is boiled off in a two-level vat within the kamaya vat shed. A single round of boiling can produce around 100 kilograms of salt. Rather than boiling off the entire solution, the salt is extracted with some liquid remaining in the vat. This liquid solution is called nigari (“the bitters”), and it contains many other minerals originally contained in the seawater. Separating out this nigari is the secret behind Utazu salt’s lack of bitterness and smooth flavor. 

The boiled-off salt is extracted from the solution and placed in a wooden tray called a shiodoko. Workers then drain away any remaining moisture content from the tray, leaving the finished product. This relatively unprocessed Utazu salt contains high levels of calcium and potassium. Locals say that the best use for Utazu salt is in salted rice balls, appropriated named shio-musubi (“salted rice balls”), but it is also popularly used for barbequed meats, raw fish, salted caramel, and salt candies.