Go Back
Cold brew katsuo dashi in a jar on the left and regular dashi on the right.

Katsuo Dashi (Easy Bonito Dashi Recipe with Katsuobushi)

5 from 1 vote
Make katsuo dashi with bonito flakes in 15 minutes. This easy bonito dashi recipe brings deep umami flavor with just a few simple steps.
Print Recipe Pin Recipe
Cook Time 15 hours
Total Time 15 hours
Servings: 800 ml
Course: condiments
Cuisine: Japanese
Calories: 5
Ingredients Method Notes

Ingredients
  

  • 4 cups filtered water 960 ml
  • 30 g katsuobushi (bonito flakes) about 2 cups, tightly packed

Method
 

Option 1: Cold Brew (Overnight Method)
  1. Prep: Add 30 g katsuobushi (bonito flakes) and 4 cups filtered water to a container. Tip: Use a disposable teabag or infuser for easy straining later.
  2. Refrigerate and Steep: Cover and chill in the fridge for 8 to 24 hours.
  3. Strain: Strain out the bonito flakes and use your dashi right away or store for later.
Option 2: Stovetop Method (Quick)
  1. Heat the Water: Pour 4 cups filtered water into a medium pot and heat gently. Stop when small bubbles start rising; do not boil.
  2. Add and Steep Katsuobushi: Turn off the heat and add 30 g katsuobushi (bonito flakes). Let it steep quietly for 1 to 2 minutes without stirring.
  3. Strain Carefully: Pour through a fine mesh strainer or paper towel-lined colander. Let the flakes drain naturally, don’t squeeze!
(Optional) Niban Dashi (Second Brew)
  1. Start the Second Brew: Add used bonito flakes and 2 cups fresh water to a pot, then bring to a boil.
  2. Simmer: Lower the heat and simmer for 3 to 5 minutes.
  3. Add Fresh Katsuobushi: Turn off the heat and add 5g fresh bonito flakes (about ⅓ cup tightly packed).
  4. Final Steep: Let these fresh flakes steep for 1 to 2 minutes.
  5. Strain and Extract: Strain the dashi and gently squeeze the flakes this time to get all the flavor out.

Notes

  • Water: Soft water extracts more umami. If your tap water is hard (like in many parts of the U.S.), use filtered water (e.g., Brita).
  • Katsuobushi (Bonito Flakes): Use thin-shaved flakes (usu-kezuri), like Kaneso Hanakatsuo. Avoid powdery “topping” flakes; they’re not meant for dashi.
  • Katsuobushi Ratio (to Water)
    • 4% = Strong dashi for clear soups, chawanmushi
    • 3% = Balanced flavor, great for cooking outside Japan (recommended)
    • 2% = Light dashi for everyday home use
  • Reusing Ingredients:
    Use spent kombu/katsuobushi for:
    • Furikake (pan-toast with soy sauce/mirin)
    • Okaka (mix with soy sauce for onigiri filling)
    • Dashi soy sauce (soak in soy sauce)
    • Dashi ponzu (soak in ponzu)
  • How to Use Katsuo Dashi: Great for miso soup, oden, dashimaki tamago, or any dish that needs a rich umami base, even simple simmered veggies!
  • Storage Instructions: 
    • Dashi: Store in an airtight container for up to 3 days in the fridge or 2 weeks in the freezer (ice cubes work great for small portions).
    • Used Katsuobushi: Pat dry and store in an airtight container for up to 1 week in the fridge or 1 month in the freezer.
QR Code linking back to recipe