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 - and a few of them are especially relevant when you start cooking for a baby.

• Kombu dashi - made from kelp only. Clean, gentle, vegetarian, and the first dashi recommended for babies in early weaning.
• Katsuo dashi - made from bonito flakes only. Light and aromatic, used for clear soups.
• Awase dashi - kombu and bonito combined. The all-purpose standard for everyday Japanese cooking.
• Niban dashi - the 'second' dashi made by re-simmering used kombu and bonito. Milder, good for simmered dishes.
• Niboshi (iriko) dashi - made from dried baby sardines. Stronger and fishier, popular for miso soup.
• Shiitake dashi - dried shiitake soaked in cold water. Vegan, deeply savoury, lovely combined with kombu.

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), enough for four servings of miso soup or one batch of simmered dishes. The whole process takes about 30 minutes, most of which is hands-off.

1. 01Wipe the kombu lightly with a dry cloth to remove debris, but never wash off the white powder - that is concentrated umami.
2. 02Place the kombu in 1 litre of cold water and let it soak for 30 minutes (or up to a few hours for deeper flavour).
3. 03Heat the pot slowly over medium-low. Just before the water comes to a boil and small bubbles rise around the kombu, remove the kombu. Boiling it makes the dashi bitter and slimy.
4. 04Bring the water to a gentle boil, then add the katsuobushi all at once. Turn off the heat immediately.
5. 05Let the bonito flakes steep for about 1-2 minutes until they sink. Do not stir or squeeze.
6. 06Strain through a fine sieve lined with kitchen paper. Do not press the flakes - let it drip naturally to keep the dashi clear. Your ichiban dashi is ready.

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.

Dashi for Babies

Dashi is the secret to Japanese baby food. It lets you make plain vegetables and rice taste savoury and satisfying without any salt, which babies' developing kidneys cannot yet handle. Start with kombu dashi only in early weaning (around 5-6 months), since bonito introduces fish. From the middle stage (7-8 months), once fish has been introduced, you can move to awase dashi. Always use unsalted, homemade or baby-specific dashi for infants - never instant dashi powder, which contains added salt. See our Baby Dashi Guide and the weaning stage guides on the blog for full detail.

• Early stage (5-6m): kombu dashi only, no salt.
• Middle stage (7-8m) onward: awase (kombu + bonito) dashi, still no salt.
• Freeze dashi in ice-cube trays for easy baby-sized portions.
• Avoid instant dashi powder for babies - it contains added salt and flavour enhancers.

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.

Can babies have dashi?

Yes - unsalted dashi is a cornerstone of Japanese weaning. Use kombu-only dashi in the early stage (5-6 months), then awase dashi once fish has been introduced (around 7-8 months). Never use instant dashi powder for babies, as it contains added salt. Homemade dashi or unsalted baby-specific dashi granules are best.