Recipes > Kombu Dashi | Kelp Stock

Kombu Dashi | Kelp Stock


Dashi is Japanese stock that is used as the base to flavor many Japanese dishes, such as miso soup. There are various types of dashi. This plant-based kombu dashi is very easy to make. In fact, it can even be made just by soaking the seaweed in water overnight.
  • Serves: 4 cups
  • Active Time: 5 mins
  • Total Time: 5 mins
  • Views: 28,346
  • Success Rating: 100% (?)
    0% - I fed it to the dog


Step 1: Making the Kombu Dashi | Mizudashi

Making the Kombu Dashi | Mizudashi
  • 20 grs kombu seaweed
  • 4 cups cold water


To make the dashi, gently wipe any sand that may be on the kombu with a damp cloth, but leave the white powdery substances as this contributes to the umami in the dashi.

Next, place the kombu into a large measuring cup or glass jug and then add the water. Let steep, in the refrigerator. overnight (approximately 10 hours). The kombu’s natural flavor comes out just from soaking it in the water.

Strain the dashi. It is now ready to be used. Store in the refrigerator for up to a week, or freeze for later use.

The kombu can be sliced and added to soups, stews, or salads.

*Note: To save time, you can also make the dashi using boiling water (nidashi). To do this, place the kombu and water into a pot and slowly heat over low heat for approximately 20 minutes. Skim the surface as needed. Just as the dashi comes to a simmer, remove the kombu and discard it. If you leave the kombu in, it will become slimy and potentially bitter tasting. Once done, strain and store as mentioned above — just be sure to cool the stock properly before storing.

Chef's Notes

Here is a simple, yet delicious recipe for Miso Soup.


  • Janet C
    Janet C
    Thank you for this advice.. I want to make miso soup tonight, and only saw the recipe for dashi now, so I appreciate the quick method!
  • Liane A
    Liane A
    What is the purpose of "whipping" the kombu with a damp cloth? Are we worried the kombu may be dirty?
  • Eric W Rouxbe Staff
    Eric W
    Liane, first, I'll say that the wiping (spelling corrected; thanks!) is usually an optional step. But, what you want to look for is any sand that may be adhering to the kombu and gently remove it with a towel. Otherwise, the powdery white substance on the surface is fine to eat.
  • Bibi O
    Bibi O
    Hi, any other seaweed can be use?
  • Ken R Rouxbe Staff
    Ken R
    Bibi - Kombu is really the best option to use but you can try others to add a unique oceanic flavor. ~Ken
  • Bibi O
    Bibi O
    I can't stop making this recipe. So delicious, much better than the restaurant one. Thanks so much.
  • Char N Rouxbe Staff
    Char N
    Hi Bibi: thanks for writing. I like this recipe because it is so easy and delicious. Sounds like it is a keeper recipe for you. Cheers, Char
  • Kate G
    Kate G
    How much kombu do you use? 20grs? Does this recipe call for 20 grams for 4 c H2O? The package I have is 50 g and instructions are cut a strip (which is about 6” long and 1/2 “ wide) and put in water(amount not specified). Thank you
  • Eric W Rouxbe Staff
    Eric W
    Kate, this recipe call for 20 grams of kombu per quart/4 cups or liter of water. Try making this with two pieces of kombu from your package. See how you like the results and make adjustments, as needed.
  • Kate G
    Kate G
    Thank you, I’ll give it a try!
  • Catherine B
    Catherine B
    Thank you so much for this recipe -- It's super easy and delicious.
  • Mary E
    Mary E
    I am a bit concerned about the amount of iodine in kombu. I had been planning to make dash some time ago, but decided against it due to the iodine content. There seems to be about 2353 mcg of iodine per gram and as the recommended daily amount is 150mcg, that's about 15 days worth per gram, and the recipe has 20g. Do you know how much iodine would leach into the water during lengthy soaking. I notice that Clearspring's organic kombu comes with a warning of its high iodine content.
  • Eric W Rouxbe Staff
    Eric W
    Hi Mary, I don't know how much iodine may end up in the water. You might reach out to a food science lab at a university with your question. ~Eric
  • Barbara H
    Barbara H
    I am highly allergic to seaweed..... is there anything I can substitute for the seaweed?
  • Eric W Rouxbe Staff
    Eric W
    Hi Barbara, No, not in this case, as this is a kelp stock. But, another type of stock that aligns with some Japanese dishes is shiitake stock. Of course, other vegetables can be used, too, according to your preference. ~Eric
  • Ileana C
    Ileana C
    I can't wait to try it. Thank you!

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