Japanese Instant Pot Dashi Powder

Name: Japanese Instant Pot Dashi Powder
Prep time: 10 min
Cook time: 15 min
Total time: 25 min
Yield: 6 servings
Cuisine: Japanese
Ingredients: 1½ oz (42 g) kombu seaweed, dried, wiped clean with a damp cloth, cut into 1-inch pieces; 2 oz (56 g) bonito flakes (katsuobushi), dried, loosely broken into small pieces; ½ tsp (3 g) fine sea salt; ¼ tsp (½ g) white pepper, freshly ground; 1 tbsp (18 ml) hon-mirin (pure mirin)

From the MyKitchenBank Kitchen

A homemade dashi powder blend made in the Instant Pot, capturing the umami-rich flavors of kombu seaweed and bonito fish. This convenient powder dissolves instantly in hot water to create authentic Japanese dashi broth for soups, noodles, and sauces. By toasting and dehydrating the ingredients under pressure, you concentrate their flavors and create a shelf-stable blend that tastes fresher than store-bought versions.

Prep: 10 min
Cook: 15 min
Wait: 45 min
Total: 1 hr 10 min
Makes: About ⅔ cup (160 ml) dashi powder

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Steps

Before you start

Read through all steps—the Instant Pot is used only for steaming to dry the ingredients, not for high pressure cooking
Ensure your kombu and bonito flakes are fresh and have no off odors
Have a fine spice grinder or food processor ready for the final grinding step

1
Prepare the Instant Pot
- Add 1 cup (240 ml) of water to the Instant Pot and place the trivet on the bottom.
- Line the trivet with parchment paper or cheesecloth to prevent the ingredients from falling through the holes.
- Set the Instant Pot to the "Keep Warm" setting so it stays ready.
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Tip: The water is only for creating steam; ingredients will sit above it on the trivet.
2
Toast kombu pieces
- Heat a dry skillet over medium heat.
- Add the kombu pieces and toast for 2 minutes, stirring frequently, until they become slightly darker and fragrant.
- This releases their umami compounds.
- Transfer immediately to a plate to cool.
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Ready when: Kombu darkens slightly and becomes fragrant
Tip: Don't over-toast or the kombu will become bitter. Keep heat moderate.
3
Toast bonito flakes
- In the same skillet, add the bonito flakes and toast over medium heat for 1 minute, stirring constantly.
- The flakes should become even lighter in color and release a savory fish aroma.
- Transfer to another plate immediately.
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Ready when: Bonito flakes are lighter, more fragrant, and slightly crisp
Tip: Bonito toasts faster than kombu—watch closely to avoid burning.
4
Arrange on Instant Pot trivet
- Spread the toasted kombu and bonito flakes evenly on the parchment-lined trivet in the Instant Pot.
- Do not stir them together yet; arrange them in a single layer.
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Tip: A single layer allows even drying during the steaming phase.
5
Steam to dry and concentrate flavors
- Close the Instant Pot lid and set to high pressure with the vent sealed.
- Cook for 5 minutes at high pressure (this steams and further dries the ingredients).
- When complete, allow natural pressure release for 10 minutes, then manually release any remaining pressure.
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Ready when: Pressure releases and ingredients feel completely dry and crisp when touched
Tip: Natural pressure release prevents moisture from condensing back onto the ingredients.
6
Cool and dry the mixture
- Transfer the steamed kombu and bonito flakes to a clean, dry plate.
- Spread them in a single layer and allow to cool completely at room temperature for 20 minutes.
- They will become even more brittle as they cool.
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Ready when: Ingredients are completely cool, very brittle, and snap easily
Tip: Cool ingredients grind more uniformly into powder.
7
Grind to powder
- Working in two batches, place the cooled kombu and bonito flakes in a spice grinder or food processor.
- Grind each batch until it reaches a fine powder—about 30 seconds per batch.
- Sift the powder through a fine-mesh sieve, returning any larger pieces to the grinder and processing again until all ingredients are finely ground.
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Ready when: Powder passes through sieve easily; no large flakes remain
Tip: Sifting twice ensures a uniform, fine powder that dissolves instantly in water.
8
Mix in seasonings
- Transfer the finely ground powder to a small bowl.
- Add the sea salt, white pepper, and mirin.
- Stir well with a fork, breaking up any clumps, until the seasonings are evenly distributed throughout the powder.
- Mirin will add a subtle sweetness and help bind the mixture.
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Ready when: Seasonings are evenly mixed; no white pepper specks or salt crystals visible in clumps
Tip: Mirin is slightly sticky, so break up any lumps carefully with a fork to keep powder dry.
9
Store in airtight jar
- Transfer the finished dashi powder to a clean, dry airtight glass jar.
- Seal tightly and label with the date.
- Store in a cool, dark cupboard away from heat and light.
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Tip: Glass jars keep moisture out better than plastic; ensure the lid seals completely.

Good to know

Tips

For extra umami depth, add ¼ tsp of MSG (monosodium glutamate) or ½ tsp of nutritional yeast to the seasoning step. Both enhance the savory notes naturally.
Toast the kombu and bonito separately—they cook at different rates. Bonito burns quickly, so watch it closely.
Make sure all equipment and jars are completely dry before use. Any moisture can cause the powder to clump and spoil faster.
Use this powder as an instant soup base (1 tsp per cup of hot water), to dust noodles, season sauces, or sprinkle on roasted vegetables for a quick umami boost.

Make ahead

This dashi powder can be made up to 1 month ahead. Store in an airtight glass jar in a cool, dark cupboard. The flavors remain bright and concentrated for at least 3 weeks; after that, some potency may fade.

Storage & reheating

Room temperature (cool, dark cupboard): up to 1 month. Do not refrigerate. Freezer: not recommended, as moisture can accumulate when thawing. To use: dissolve 1 teaspoon of powder per 1 cup (240 ml) of hot water to make instant dashi broth.

Substitutions

bonito flakes (katsuobushi), dried → dried anchovy or niboshi, finely ground. Anchovy creates a slightly more mineral, less sweet umami flavor. Use the same weight (56 g).
kombu seaweed, dried → dried shiitake mushroom, finely chopped. Shiitake adds earthy umami; use 28–35 g. The powder will be darker but equally flavorful.
hon-mirin (pure mirin) → sugar or honey, 1 tsp. Sugar or honey provides sweetness but lacks mirin's depth. Omit if you prefer a savory blend.
white pepper, freshly ground → black pepper, freshly ground, 0.25 tsp. Black pepper is slightly more robust; white pepper is traditional and more delicate in dashi.