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Dashi Calculator — Kombu, Bonito & Stock Ratios

Get precise kombu, bonito, and timing for any dashi type and volume

Kombu

10.0g

Bonito

30.0g

Steep

3min

Ichiban Dashi (First Extract)

1.0 L
Delicate, clear stock for soups
Kombu

10.0g

Bonito Flakes

30.0g

Steep Time

3 min

Ingredient Amounts

Kombu10.0g
Bonito Flakes30.0g

Example Calculations

11 Liter of Ichiban Dashi

Inputs

Volume1000 ml
TypeIchiban Dashi (First Extract)

Result

Kombu10g
Bonito Flakes30g
Steep Time3 min

1L × 10g kombu/L = 10g kombu. 1L × 30g bonito/L = 30g bonito. Ichiban steep: 3 minutes.

2500ml Kombu Dashi (Vegetarian)

Inputs

Volume500 ml
TypeKombu Dashi (Vegetarian)

Result

Kombu10g
Bonito Flakes0g
Steep Time30 min

0.5L × 20g kombu/L = 10g kombu. No bonito (vegetarian). Steep: 30 minutes.

Frequently Asked Questions

Q

How much kombu do I need for dashi?

Kombu amounts vary by dashi type: ichiban dashi uses 10g per liter, niban uses 15g, and kombu-only (vegetarian) dashi uses 20g per liter. Wipe kombu with a damp cloth but never wash it—the white powder on the surface is glutamic acid, the source of umami.

  • Ichiban dashi: 10g kombu per liter of water
  • Niban dashi: 15g kombu per liter (reuse from ichiban)
  • Kombu dashi (vegetarian): 20g kombu per liter for deeper flavor
  • Iriko dashi: 10g kombu + 30g dried sardines per liter
  • Never boil kombu — remove at 60–70°C to avoid sliminess
Dashi TypeKombu/LBonito/LSteep Time
Ichiban10g30g3 min
Niban15g40g10 min
Kombu Only20g0g30 min
Iriko10g0g (+30g sardines)5 min
Shiitake0g0g (+20g mushrooms)6 hr
Q

What is the difference between ichiban and niban dashi?

Ichiban (first) dashi is a delicate, clear stock made with fresh kombu and bonito, steeped for only 3 minutes. Niban (second) dashi reuses the ichiban ingredients with additional kombu and bonito, simmered 10 minutes for a stronger, less refined flavor suited to simmered dishes.

  • Ichiban: fresh ingredients, 3-minute steep, clear and delicate
  • Niban: reuses ichiban ingredients plus extra, 10-minute simmer
  • Ichiban is for: miso soup, clear soup (suimono), chawanmushi
  • Niban is for: simmered dishes (nimono), noodle soups, stews
  • Some recipes make a third extraction, but flavor is very faint
Q

How do I make vegetarian dashi?

Vegetarian dashi uses either kombu alone (20g per liter, soaked 30 minutes) or shiitake mushrooms (20g dried per liter, soaked 6+ hours). Combining both creates the deepest umami. Kombu dashi is ready in 30 minutes; shiitake dashi is best soaked overnight in the refrigerator.

  • Kombu dashi: 20g kombu per liter, soak 30 min at 60–70°C
  • Shiitake dashi: 20g dried shiitake per liter, cold-soak 6+ hours
  • Combined: 10g kombu + 10g shiitake per liter for maximum umami
  • Cold-soak method: refrigerate overnight for cleanest flavor
  • Avoid boiling kombu—it releases bitter, slimy compounds
Q

How long does dashi last?

Fresh dashi lasts 3–5 days refrigerated and up to 3 months frozen. Store in airtight containers and freeze in ice cube trays for convenient single-serving portions. Dashi loses its delicate flavor after 24 hours, so it is best used the same day for clear soups.

  • Refrigerated: 3–5 days in an airtight container
  • Frozen: up to 3 months, freeze in ice cube trays
  • Best flavor: use within 24 hours for clear soups
  • Reheating: warm gently, never boil after straining
  • Instant dashi (hondashi) is a convenient substitute at 1 tsp per cup

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Last Updated: Mar 20, 2026

This calculator is provided for informational and educational purposes only. Results are estimates and should not be considered professional financial, medical, legal, or other advice. Always consult a qualified professional before making important decisions. UseCalcPro is not responsible for any actions taken based on calculator results.

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