What is dashi?
What is it made of, how does it taste, and how many kinds are there?
And most of all, why is it vital to Japanese cuisine?
Dashi is almost always included in every typical Japanese dish. It’s no exaggeration to say that the taste of Japanese cuisine is based upon the taste of dashi. In other words, dashi is the foundation of washoku.
There are many ways to make dashi. A variety of ingredients can be used, such as kombu (a type of kelp found mainly in Japan), katsuobushi (dried shavings of skipjack tuna or bonito flakes), niboshi (dried sardines), shiitake mushrooms, the leftovers of filleted fish, etc. It can be made by boiling the ingredients, or by leaving them to soak in water for a few days. What’s more, the “first” dashi (made from the first infusion of ingredients) will taste significantly different from the “second” dashi (made by re-infusing ingredients used to make the first dashi), and will be used for different kinds of dishes. So the character of each washoku dish depends on the type of dashi used.
What does dashi taste like, and why?
Dashi has an umami taste. Discovered by a Japanese researcher, umami is the fifth basic taste sensation (along with sweet, sour, salty and bitter), and is currently acknowledged as such worldwide. There are three specific amino acids that contain the taste we’ve come to know as umami: glutamate, guanylate and inosinate. Konbu, shiitake and katsuobushi, the most frequently used dashi ingredients, each respectively contain an abundance of glutamic, guanylic and inosinic acids.
Although each of these three components yield an umami taste, when combined the taste is even stronger. For example, when making dashi, instead of using only kombu or only katsuobushi, first boil the former, then add the latter. The reason for doing so is that the concentration of amino acids in each of those ingredients is not very high, but through their combined synergy, the taste is disproportionately stronger!
There are other ways of creating this synergy. For example, when making yudofu, or boiled tofu, it is common to use a kombu dashi for boiling, then to dip the tofu into a dish of katsuobushi and soy sauce.
Making maximum use of the synergy of umami is central to the daily Japanese diet. The main source of that umami is dashi, the foundation of the washoku taste. Without the umami of washoku, Japanese cuisine wouldn’t be what we know and love today. So in the quest for understanding washoku, I think it’s not a stretch to say "no dashi, no life; know dashi, know life”.