Dashi and osumono (Japanese seasonal soups)

I have a video that details the process (link at bottom), but in short:

The process is simple but keep in mind that there are dozens of varieties of kelp (kombu) and katsuo (bonito) that people use, so it’s easier to think in terms of ratio when making dashi. Keep notes as to the proportion and ingredients you use so you can learn how to adjust. Having said that, the basic ratio is 1 - 2 percent konbu and katsuo to water (I have a chef friend who uses 3% katsuo, so there’s a lot of personal preference involved).

1000ml water
10-20 grams konbu (dried kelp)
10-20 grams katsuo flake (bonito flakes)


  1. Soak the konbu over night, but no more than 24 hours or the water becomes ‘slimy’.
    Heat that water to the simmer and add your katsuo flakes. Keep the water under the boil and cook for no more than two minutes (if and when the katsuo sinks to the bottom of the pan, that’s the sign the dashi is finished).

  2. Strain through a fine mesh sieve, paper towel, or coffee filter to remove any particulate (for the clearest possible soup) – do not press the solids.

Now you have dashi.

To make ‘soup’ for osumono (Japanese seasonal soups)

1 teaspoon light soy sauce
1/4 teaspoon salt
400ml of the dashi

add the salt and soy sauce to the dashi and bring to a simmer. Ladle into bowls of cubed tofu, poached fish, forcemeats or seasonal vegetables.


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I make dashi pretty often, and I’d love some ideas about using it in cold preparations, now that the weather is warming up -got any?. My usual source is Just One Cookbook.

Well, the easiest recipe for something cold and delicious would be ochatsuke, which is rice over which green tea, hoji tea, or dashi is poured. In summer cold dashi is the best. Add flavor by including umeboshi, minced scallions, or sesame seeds – yum.

A little more work, a ‘boom’ over here is to marinade skinned whole tomatoes in dashi over night with vegetables that don’t have an overly strong flavor like okra and cucumber and serve like a soup. On TV the other night I saw a variation in which they put dashi tamago (think Japanese rolled omelette) in with the “soup”. It looked really good – and thought I’ve not tried it, I’ll bet a little cold dashi would improve gazpacho.

All kinds of 'forcemeats" of fish are steamed or poached then served with hot or cold dashi. Actually, because I like to increase my protein intake (for the gym) I often put chicken breasts in the food processor with with an egg potato/corn starch and whip in a strong dashi. I poach it and keep it in the fridge for when I need a protein boost. It’s really good with splash of soy sauce and/or chili oil.


Is it possible to make a flavorful dashi without the inclusion of bonito or other fish products? I’ve been looking for a vegan option.

Sure. You can use dried shiitakes instead of bonito.

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Yes and no.

Outside Japan, people use the word ‘dashi’ to mean any and all of the soup stocks used in Japanese cuisine, so in that sense, yes. But a dashi made from shitake or konbu only is as different to a dish as would be substituting cashews for peanuts in making a Reeces Peanut Butter Cup, so in that sense, no.

In the end, every recipe becomes the cooks own, so give it a try.

“Food is a pretty good prism through which to view humanity.”

― Jonathan Gold