Kombu Dashi | Easy Japanese Recipes at JustOneCookbook.com

Kombu Dashi (Vegetarian Dashi)

Course: Condiments
Cuisine: Japanese
Keyword: broth, soup stock, umami
Prep Time: 5 minutes
Cook Time: 25 minutes
Total Time: 30 minutes
Servings: 800 ml (800 ml = 3⅓ cups)
Learn how to make Kombu dashi at home and create the umani flavor for your Japanese dishes! 


  • oz kombu (dried kelp) (10 g, 4" x 4" OR 10 cm x 10 cm) (You can add more for stronger flavor)
  • 4 cups water (roughly 1000 ml)


  1. Gather all the ingredients. 

    Kombu Dashi Ingredients
  2. Gently clean the dashi kombu with a damp cloth but leave the white powdery substance (Mannitol) which contribute to the umami flavor in dashi. Do not wash the kombu! I usually look at the kombu carefully to make sure it's clean, then I use it right away.
    Kombu Dashi 1
  3. Make a couple of slits on the kombu.
    Kombu Dashi 2

Make Kombu Dashi with Water (mizudashi)

  1. Put water and kombu in a large bottle and let it steep on the counter for 2-3 hours in the summertime and 4-5 hours in the winter time. If you don't plan to use it right away, you can start steeping in the fridge from the beginning. 
    Kombu Dashi 3
  2. Remove the kombu (you can make simmered kombu or furikake rice seasoning with leftover kombu). Kombu dashi is now ready to use. You can keep kombu dashi the refrigerator for 3-4 days or in the freezer for 2 weeks. I recommend using it sooner for the best flavor.

Make Kombu Dashi with Boiling Water (Nidashi)

  1. In a medium pot, put the kombu and water. If you have time, soak for 3 hours or up to half day ahead of time. Kombu’s flavor comes out naturally from soaking in water.
    Kombu Dashi 4
  2. Heat up the pot slowly on medium low heat. It will take 20-25 minutes to a boil. Meanwhile, clean the dashi by skimming the surface.
    Kombu Dashi 5
  3. Just before the dashi starts boiling, remove kombu (you can make simmered kombu or furikake rice seasoning with leftover kombu). If you leave the kombu inside, the dashi will become slimy and bitter.
    Kombu Dashi 6
  4. Over a large bowl, set a fine-mesh sieve and strain the dashi.
    Kombu Dashi 7
  5. If you are not using the dashi right away, save it in a bottle and keep in the refrigerator for 3-5 days or in the freezer for 2 weeks.
    Kombu Dashi 8

Recipe Notes

Equipment you will need: 



Recipe by Namiko Chen of Just One Cookbook. All images and content on this site are copyright protected. Please do not use my images without my permission. If you’d like to share this recipe on your site, please re-write the recipe and link to this post as the original source. Thank you.