How to Make Dashi (Japanese Stock)

Dashi is the invisible backbone of Japanese cuisine. It is a stock so fundamental that most Japanese people do not even think of it as a separate component — it is simply the starting point of cooking. Unlike Western stocks that simmer for hours, dashi is made in minutes. This speed is by design: dashi extracts clean, pure umami without the heaviness of a long-cooked broth. If you learn to make one thing before attempting any Japanese recipe, make it dashi. The difference between a dish made with good dashi and one made with water is the difference between food that tastes Japanese and food that merely looks Japanese.

What is Dashi?

Dashi is a cooking stock that forms the base of most Japanese soups, sauces, and simmered dishes. It is made by briefly steeping dried ingredients — most commonly kombu (dried kelp) and katsuobushi (dried bonito flakes) — in water. The result is a light, clear broth with deep umami flavor. The concept of umami, the fifth basic taste, was actually discovered by studying kombu dashi. Japanese scientist Kikunae Ikeda identified glutamate as the source of kombu's savory flavor in 1908, launching the modern understanding of umami.

Types of Dashi

There are several types of dashi, each suited to different dishes. Understanding which to use will improve your Japanese cooking immediately.

• Awase Dashi (combined dashi) — Made from both kombu and katsuobushi. The most versatile and commonly used. Perfect for miso soup, noodle broths, and simmered dishes.
• Kombu Dashi — Made from kombu only. Vegetarian and vegan. Subtle, clean flavor. Good for delicate dishes where you don't want a strong fish flavor, and as a base for hot pot (nabe).
• Katsuo Dashi — Made from katsuobushi only. Stronger, smokier flavor. Often used for dipping sauces (tentsuyu for tempura, soba tsuyu) and clear soups.
• Iriko Dashi — Made from dried sardines (niboshi). Stronger, fishier flavor popular in western Japan. The traditional base for hearty miso soups and rural home cooking.
• Shiitake Dashi — Made by soaking dried shiitake mushrooms. Rich, earthy umami. Excellent vegetarian option and commonly used in Buddhist temple cuisine (shojin ryori).

How to Make Awase Dashi

This is the standard dashi recipe used in most Japanese home kitchens. It makes about 800ml of primary dashi (ichiban dashi), which is enough for 4 servings of miso soup or one batch of simmered dishes.

1. 01Place kombu in a pot with 1 liter of cold water. Let it soak for at least 30 minutes, or up to overnight in the fridge for deeper flavor.
2. 02Place the pot over medium heat. Heat slowly — this gradual warming extracts glutamate from the kombu without releasing bitter, slimy compounds.
3. 03Just before the water reaches a boil (you'll see small bubbles forming at the edges), remove the kombu. Do not boil the kombu — boiling makes the dashi cloudy and bitter.
4. 04Bring the water to a full boil. Turn off the heat.
5. 05Add katsuobushi all at once. Let it steep for 30 seconds to 1 minute without stirring.
6. 06Strain through a fine-mesh sieve lined with a paper towel or cloth. Do not squeeze the bonito flakes — pressing them releases bitter compounds.
7. 07Your dashi is ready. Use immediately or refrigerate for up to 3 days.

Instant Dashi: When to Use It

There is no shame in using instant dashi powder (dashi no moto). Even in Japan, the majority of home cooks use it for everyday cooking. Brands like Shimaya and Ajinomoto make reliable instant dashi. Dissolve 1 teaspoon of dashi powder in 400ml of hot water for a quick stock. Reserve homemade dashi for dishes where the broth is front and center — clear soups (suimono), chawanmushi (egg custard), and fine noodle dipping sauces. For miso soup, simmered dishes, and stir-fry sauces, instant dashi works perfectly well.

Storing and Reusing Dashi

Fresh dashi should be used the same day for the best flavor. It can be refrigerated in an airtight container for up to 3 days, or frozen in ice cube trays for up to a month. The leftover kombu and katsuobushi from making primary dashi can be reused to make secondary dashi (niban dashi) — simply simmer them in water for 5 minutes. Niban dashi is weaker but perfectly suitable for simmered dishes, miso soup, and cooking rice.

Frequently Asked Questions

Where can I buy kombu and katsuobushi?

Both are available at Japanese grocery stores, Asian supermarkets, and online retailers like Amazon. Kombu is usually sold in dried sheets, and katsuobushi is sold pre-shaved in bags. Look for them in the dried goods or soup section.

Can I make vegetarian dashi?

Yes. Kombu dashi (kombu only) and shiitake dashi (dried shiitake mushrooms soaked in cold water overnight) are both vegetarian and vegan. For the richest vegetarian dashi, combine both: soak kombu and dried shiitake together in cold water overnight.

How is dashi different from chicken or beef stock?

Dashi is lighter, cleaner, and faster to make than Western stocks. It relies on umami (glutamate from kombu + inosinate from bonito) rather than the collagen and fat extracted by simmering bones. The flavor profile is subtle and designed to enhance other ingredients, not dominate them.

Why does my dashi taste bitter?

The most common causes are: boiling the kombu (remove it just before the water boils), steeping the katsuobushi too long (30 seconds to 1 minute is enough), or squeezing the bonito flakes when straining. Any of these will release bitter compounds.