To make dashi, soak a piece of kombu in cold water, bring it just to a simmer, then remove the kombu and add bonito flakes before straining after a few minutes. The whole process takes about fifteen minutes and needs only two ingredients. Dashi is the base stock behind miso soup, udon broth, and many Japanese sauces.
Kombu and bonito flakes are not always easy to find on the average UK high street. This guide covers the method and where to buy both ingredients online.
What you need
| Ingredient | Amount |
|---|---|
| Dried kombu | A 10cm piece |
| Bonito flakes (katsuobushi) | 15g |
| Cold water | 1 litre |
Method
- Wipe the kombu with a damp cloth rather than rinsing it, since the white residue on the surface carries flavour.
- Soak the kombu in the cold water for at least 30 minutes, or overnight in the fridge for a stronger flavour.
- Heat the water and kombu gently until just before boiling, then remove the kombu straight away. Boiling it makes the dashi bitter and slimy.
- Add the bonito flakes and bring back to a simmer for 30 seconds, then turn off the heat.
- Let the flakes settle for a few minutes, then strain through a fine sieve or muslin cloth.
A quicker version with dashi powder
Instant dashi powder is a reasonable shortcut for a weeknight meal. Mix around one teaspoon of powder into 500ml of hot water and stir until dissolved. It lacks some of the depth of dashi made from scratch, but works well in miso soup and quick noodle broths.
Where to buy kombu and bonito flakes in the UK
Both are stocked by larger Japanese and Asian supermarkets in cities such as London, and by several UK-based Japanese grocers online who deliver nationwide. If you cannot find them locally, ordering online is usually the most reliable option, since both ingredients keep for months unopened.
FAQ
Can I reuse the kombu and bonito flakes?
Yes. A second, weaker stock called niban dashi can be made by simmering the used kombu and flakes again in fresh water, useful for everyday cooking where a lighter flavour is fine.
Can I make dashi without bonito flakes?
Yes. Kombu alone makes a vegetarian dashi, often combined with dried shiitake mushrooms for extra depth.
How long does dashi keep in the fridge?
Around three to four days in a sealed container. It also freezes well for up to a month.
Is dashi the same as fish stock?
Not exactly. Dashi is lighter and more delicate than a Western fish stock, made quickly rather than simmered for a long time.
New to the ingredient? Start with what is dashi. Once your stock is ready, use it as the base for a bowl of udon, following the timings in our how to cook udon noodles guide.
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- Dried kombu seaweed. The base ingredient for a proper dashi stock.
- Bonito flakes. Adds the deep, smoky flavour dashi is known for.
