A 750-Year-Old Secret: See How Soy Sauce Is Still Made Today | Short Film Showcase

In a small coastal town in Wakayama Prefecture, Japan, the traditional streets and buildings hold one of the best-kept secrets of Japanese Gastronomy. For it was here, in the 13th century, that soy sauce, as we know it, was first established and produced. This is Yuasa, the birthplace of soy sauce.

In 1254, a Buddhist monk arrived back from his travels in China and settled in Wakayama Prefecture. He had learned of a kind of miso made to preserve summer vegetables and set to work producing it in the neighboring town of Yuasa, where there was an abundance of clear spring water. It was the liquid that collected in the barrels of miso paste that became the separate product we know as soy sauce.

Soy sauce is made from four main ingredients: soybeans, wheat, salt, and water. Like sake, Japanese vinegar, and miso, the fermentation process is enabled by the use of a starter called koji. The first stage in making soy sauce is to mix steamed soybeans and roasted wheat with the koji mold. The mixture is stored for 4 days so the koji can break down the sugars in the grain to allow for fermentation.

The koji base is next mixed with salt and water and put into huge wooden barrels to ferment for between 18 months and 3 and 1/2 years. The mash must be mixed regularly by hand. Natural yeast in the air and building act as fermenting agents. After 18 months or more, the fermented mash is poured into cloth bags and pressed to extract the liquid. This produces nama soy sauce.

The nama soy sauce is heated in a traditional iron pot over a fire of red pine logs for half a day, and the scum is taken off by hand. The resulting soy sauce is then bottled and shipped. From humble beginnings in Kishu, Wakayama, soy sauce has become a global phenomenon, but its origins are protected and maintained by a strong artisan tradition unchanged in more than 750 years in the ancient streets of Yuasa.