Ingredients:

  • 4 cups filtered water (1000 ml)
  • 1 piece dried kombu (approx. 4 x 4 / 10 grams)
  • ½ cup dried katsuobushi (bonito flakes, lightly packed / 15 grams)

Instructions:

  1. Prepare the Kombu: Using a damp cloth or paper towel, gently wipe both sides of the kombu piece to remove any grit or surface dust. Do not scrub off the white, powdery residue, as this is the source of the umami.
  2. Steep in Cold Water: Place the kombu and the 4 cups of filtered water into a medium saucepan.
  3. Gentle Heat: Place the saucepan over medium-low heat. Heat the water slowly. Watch the pot carefully; you are aiming for steam to begin rising, but not a rolling boil.
  4. Remove the Kombu: Just as the first few small bubbles begin to form on the bottom of the pan (approximately 85°C / 185°F), immediately remove the kombu using tongs. If the kombu boils, the dashi will become bitter and slimy.
  5. Bring to a Simmer: Increase the heat briefly and bring the remaining liquid up to a vigorous, rolling simmer.
  6. Introduce Bonito: As soon as the water hits a vigorous simmer, remove the pan from the heat entirely. Add the ½ cup of katsuobushi (bonito flakes) to the hot water.
  7. Steep: Gently push the flakes down so they are submerged. Let the flakes steep undisturbed for only 30 seconds.
  8. Strain: Immediately pour the entire contents of the saucepan through a fine-mesh sieve (lined with muslin or a paper filter, if a crystal-clear dashi is desired).
  9. Finish: Collect the clear dashi in a clean bowl. Do not press or squeeze the bonito flakes in the strainer, as this will release unwanted bitterness and cloudy sediment. Your dashi is ready to use!