The most common form of dashi is a simple broth or fish stock made by heating water containing kombu (edible kelp) and kezurikatsuo (shavings of katsuobushi - preserved, fermented skipjack tuna) to near-boiling, then straining the resultant liquid. The element of umami, considered one of the five basic tastes in Japan, is introduced into dashi from the use of katsuobushi. Katsuobushi is especially high in sodium inosinate, which is identified as one source of umami.
Homemade dashi, made from dried kombu and katsuobushi, is less popular today, even in Japan. Granulated or liquid instant dashi replaced the homemade product in the second half of the 20th century. Compared to the delicate nuanced taste of homemade dashi, instant dashi tends to have a stronger, less subtle flavor, due to the use of chemical flavor enhancers—glutamates and ribonucleotides.