Dashi & Umami: Building Japanese Stocks

Japanese Cookery

Chapter 3 · Dashi & Umami: Building Japanese Stocks

Dashi is the single technique this whole course leans on hardest. Miso soup, simmered dishes, sauces, even some deep-frying batters — most of it either starts with dashi directly or with something seasoned against it. Get comfortable with the three versions in this chapter and nearly every later chapter gets noticeably easier.

Handling Kombu & Katsuobushi

A couple of real, easy-to-get-wrong details before the actual methods:

The white powder on kombu is flavour, not dust Good kombu often has a faint white, powdery bloom on its surface — that's naturally occurring glutamate, the exact compound responsible for kombu's own umami. Don't rinse it off. Wipe the surface gently with a dry or barely damp cloth to remove any actual grit, and leave the bloom alone.
Never let kombu boil hard A vigorous boil pulls bitterness and a slimy texture out of kombu that a gentle heat never does. Every method below removes the kombu at or just before the water reaches a boil — this is the one rule worth never breaking.

Kombu Dashi (Vegetarian & Vegan)

The simplest dashi, and a fully plant-based one on its own. Two ways to make it:

Cold-Steep Method (easiest, most forgiving)

  1. Submerge roughly a 10cm piece of kombu in about 1 litre (4 cups) of cold water.
  2. Refrigerate for several hours, or overnight.
  3. Remove the kombu (save it — see the Niban Dashi note below) and use the liquid as is.

Quick-Heat Method

  1. Submerge the same amount of kombu in the same amount of cold water in a pot.
  2. Heat gently over medium-low heat.
  3. Just before the water reaches a boil, remove the kombu.

Awase Dashi (Kombu + Katsuobushi)

The most commonly used all-purpose dashi in Japanese home cooking, and the one most later chapters in this course assume by default.

  1. Make kombu dashi using the quick-heat method above, removing the kombu just before the water boils.
  2. Bring the kombu-infused water to a gentle simmer.
  3. Add a loose handful (roughly 15–20g) of katsuobushi.
  4. Let it steep for about 30 seconds to 1–2 minutes — do not simmer it for long.
  5. Strain through a fine-mesh strainer or cheesecloth (Chapter 1's own essential equipment).
Don't oversteep the katsuobushi Leaving katsuobushi in too long, or actively simmering it, pulls out bitter and overly fishy notes rather than the clean savoury depth you actually want. A brief steep and a prompt strain is the whole technique.

Ichiban Dashi vs. Niban Dashi

Everything above is ichiban dashi — the "first" dashi, delicate and clear. The same kombu and katsuobushi you just strained out aren't finished yet.

Ichiban Dashi (First Extraction)
  • Delicate, clear, lighter in flavour
  • Best for clear soups and dishes where the dashi itself is front and centre
  • What the method above produces
Niban Dashi (Second Extraction)
  • Made by simmering the same, already-used kombu and katsuobushi again in fresh water, for longer (10–15 minutes)
  • Stronger, more robust, less delicate
  • Better suited to miso soup and simmered dishes (Chapter 4), where other strong flavours are already in the pot

Making niban dashi from spent ichiban-dashi ingredients rather than discarding them is standard practice, not a thrifty shortcut — it genuinely produces a real, useful stock suited to a different job.

Shiitake Dashi (A Second Vegetarian Option)

Dried shiitake mushrooms make their own real, distinct dashi — earthier and more mushroom-forward than kombu alone, and a good way to add depth to a kombu dashi without using katsuobushi at all.

  1. Submerge a small handful of dried shiitake in cold water.
  2. Refrigerate and let soak for several hours, or overnight.
  3. Remove the mushrooms (they're genuinely usable in cooking afterward — don't discard them) and use the soaking liquid as dashi, on its own or combined with kombu dashi.
Cold soaking, not hot water, is deliberate Hot water rushes the extraction and can pull bitterness out of dried shiitake. A slow, cold soak draws out the flavour gently, the same underlying logic as the cold-steep kombu method above.

Kitchen Practice

Kitchen Practice 1
Make a batch of kombu dashi and taste it plain. Use either method above. Taste it warm, on its own, with nothing added. Note what "umami" actually tastes like in isolation, before it's combined with anything else.
→ Solution
Kitchen Practice 2
Make awase dashi and compare it directly against the kombu dashi from Kitchen Practice 1. Taste them side by side. Identify specifically what the katsuobushi adds that the kombu alone didn't have.
→ Solution
Kitchen Practice 3
Make niban dashi from the spent kombu and katsuobushi in Kitchen Practice 2, and compare it against the original ichiban dashi. Note the difference in strength and character, and think about which one you'd actually reach for in a miso soup versus a delicate clear soup.
→ Solution

Quick Reference — Dashi

  • Kombu: never boil hard; remove just before boiling (or cold-steep overnight)
  • Katsuobushi: add off the boil, steep briefly (30 sec–2 min), strain promptly
  • Awase dashi = kombu + katsuobushi, the default all-purpose dashi
  • Ichiban dashi (first extraction) = delicate, for clear soups
  • Niban dashi (second extraction, same spent ingredients, simmered longer) = stronger, for miso soup and simmered dishes
  • Shiitake dashi = a second, earthier vegetarian option, cold-soaked overnight
Next — Chapter 4: Simmering & Braising: Nimono Techniques
Using dashi as the base for real simmered dishes, balancing soy sauce, mirin, and sake against it.