Kombu Dashi Recipe: Cold Brew Your Way To Umami!

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Kombu dashi is one you can make with a cold brew very easily so you don’t even need to heat it.

You can make it by boiling the kombu just like any dashi recipe of course, but this just makes it so much easier.

Here’s how to do it:

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Cold Brew Kombu Dashi

Joost Nusselder
A very easy and delicious vegan cold-brew kombu dashi that couldn't. beeasier to make.
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Prep Time 15 minutes
Soaking time 30 minutes
Total Time 45 minutes
Course Lunch
Cuisine Japanese
Servings 2 people


  • Mason jar or another container for the dashi


  • 1 sheet kombu
  • 2 cups water


  • Let’s first make the vegan dashi: you’ll need two cups of water and one long piece of kombu seaweed.
    This is enough for around four people, four servings of soup but making less than this will be hard to soak the kombu in.
    Vegan dashi broth with kombu and shiitake
  • Now soak the seaweed in water for 30 minutes in a jar or a bowl. I use a mason jar for this.
    You can soak them for 12 hours in the fridge for more flavorful results. I definitely recommend doing that.
  • After the dashi has had time to soak, open the jar and remove the kombu from the water and throw them away or use it in another recipe.
    Pinch the shiitake mushrooms to release flavors
  • Now strain your stock by pouring the liquid through a fine strainer and remove any pieces of debris you see floating in it with a spoon now keep this stock in the fridge for no more than three days.
    Strain the dashi


Keyword Dashi, Vegan
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Best kombu to use

Dried kelp is a tasty and crunchy addition to the miso soup. It has that salty sea flavor and it’s super healthy for your body too!

Wel-Pac dried kombu

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Kombu Dashi

Kombu dashi uses just two ingredients, pure water and kombu kelp, making it an excellent broth option for vegans and vegetarians.

The 2 techniques used for preparing the kombu dashi are:

  1. nidashi (simmering)
  2. mizudashi (cold water extraction)

Using the nidashi technique, you must first place the kombu kelp in a pot of cold water. Then allow it to sit there for about 30 minutes – 3 hours.

Afterward, place it on top of the stove and boil the water over medium heat. Meanwhile, skim the water’s surface in order to remove any foam and keep the broth clear.

Remember to take out the kombu from the pot just before the water starts to boil. If you don’t, the dashi stock may taste bitter and slimy.

After boiling the dashi, strain the broth through a sieve to remove any foam or pieces. 

If you want to extract the dashi from kombu via cold water extraction, then cut a steep piece of kombu kelp. Next, put it in a small water container, and refrigerate it overnight.

Once done, you can pour the dashi stock into a bottle container and use it sparingly on multiple dishes.

You will notice a clear, lightly colored broth with a deep umami flavor.


Making dashi has never been easier than with a cold-brew vegan kombu dashi.

Check out our new cookbook

Bitemybun's family recipes with complete meal planner and recipe guide.

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Joost Nusselder, the founder of Bite My Bun is a content marketer, dad and loves trying out new food with Japanese food at the heart of his passion, and together with his team he's been creating in-depth blog articles since 2016 to help loyal readers with recipes and cooking tips.