Step 1

Please note that this dashi requires a minimum steeping time of 30 minutes. Ideally, we let the dashi steep for 2-3 hours in the summertime and 4-5 hours in the wintertime.

Step 2

Gather all the ingredients. Most Japanese recipes recommend gently cleaning the kombu with a damp cloth. However, kombu is pretty clean these days. Just make sure to dust off and remove mold spots, if any. Do not wash or wipe off the white powdery substance as it has lots of umami. For the dried shiitake mushrooms, check if there is any dust or dirt trapped in its gills under the caps. If there is, use a pastry brush to clean it off. Do not wash it under water.

Step 3

Put the kombu and dried shiitake mushrooms in a large bottle. Then, add the measured water.

Step 4

Put the cap on and let it steep on the counter for at least 30 minutes to extract the kombu’s flavor naturally. If possible, let it steep for 2-3 hours in the summertime and 4-5 hours in the wintertime. You can also cold brew it overnight in the refrigerator. After steeping, it's now ready to use as cold brew Vegan Dashi. You can either remove the kombu and shiitake from the bottle now, or go to the next step to extract even more flavor. See my suggestions at the end of the recipe for how to repurpose the spent kombu and shiitake.

Step 5

Transfer the cold brew Vegan Dashi, along with the kombu and shiitake, to a medium pot. Turn on the heat to medium low and slowly bring it to a bare simmer, about 10 minutes. Meanwhile, clean the dashi by skimming the foam from the surface with a fine-mesh skimmer.

Step 6

Just before the dashi starts boiling, remove the kombu and shiitake from the pot. Then, turn off the heat. Tip: If you leave the kombu in the pot, the dashi will become slimy and bitter.

Step 7

Strain the dashi through a fine-mesh sieve to catch any debris. Now, the Vegan Dashi (Shiitake Kombu Dashi) is ready to use.

Step 8

If you are not using the Vegan Dashi right away, keep it in a bottle or airtight container and store it in the refrigerator for 4-5 days or in the freezer for 2 weeks. I recommend using it sooner for the best flavor.

Step 9

Save the spent kombu in an airtight container and store it in the refrigerator for up to a week or in the freezer for up to a month.

Step 10

With the spent kombu, you can make Simmered Kombu (Kombu Tsukudani).

Step 11

You can also use it in Homemade Furikake (Rice Seasoning).

Step 12

For the spent shiitake mushrooms, cut off the tough stems with a knife and discard. You can use these rehydrated mushrooms as if you are using fresh shiitake mushrooms.