A day in Japan used to begin with the sound of the dried fish katsuo scraping over a wooden kezuriki grater: a handful or two of these fragrant shavings dropped with a piece of dried kelp kombu into a pot of near-boiling water and briefly steeped to make the delicate broth, dashi. This smoky, savory tea cuts to the core of the Japanese culinary ethos, enhancing the flavor of ingredients with the taste known as umami. A constant supply of dashi is the hallmark of any Japanese kitchen because with it, there is almost no end to the dishes you can prepare, from a simple miso soup to the slowly simmered pork belly buta kakuni.
At the turn of the 20th century, scientist Kikunae Ikeda isolated the glutamate salt in kombu responsible for dashi’s umami taste, patenting the commercial production of monosodium glutamate. The company Ajinomoto, meaning “the essence of taste,” was formed, commercially marketing MSG powder in 1909. Further research found katsuo to contain high levels of inosinates, contributing to the savory gestalt. The resulting combination was the first synthetic dashi powder, mendaciously named hon-dashi (hon meaning true). It was the spirit of the era, better living through chemistry, and the product swept across Japan and eventually the world, establishing Ajinomoto as a global brand synonymous with Japanese cooking. In that way, dashi became symbolic of food in industrialized Japan, caught between traditional methods and modern convenience. It was a battle which Ajinomoto won. Today, home cooks in Japan very rarely make dashi the old-fashioned way, and katsuo, in its original block form, is reserved for nice restaurants and specialty shops.
But that should not stop anyone from making dashi from scratch. Pre-sliced hana katsuo can be found at most Asian grocery stores, and kombu is even more widely available, since it is used by the Koreans and Chinese. Having procured those two basic ingredients, the recipe itself could not be simpler:
1 liter water
1 large sheet kombu, about an 8 inch square
30 grams katsuobushi flakes
In a stock pot, place the kombu in a liter of water (preferably soft water). Cook at medium high heat until it nears the boiling point, then remove the kombu, reserving it, and bring to a boil. Turn off the heat, add the katsuo flakes, and allow the flakes a few minutes to settle to the bottom. Strain the liquid, which should now be a beautiful pale amber color, and reserve the used katsuo along with the kombu. The steeped ingredients can be brewed again to make a lesser, “secondary” dashi, with a harsher flavor suitable for thick stews. Dashi is best when made fresh and used immediately, but can also be kept in the fridge overnight in a sealed container.