Niboshi dashi — extracted from dried baby sardines (niboshi or iriko) — is the most robustly flavoured of the Japanese primary stocks: its characteristic slightly bitter, intensely fishy-umami flavour is appropriate for miso soup (where its assertiveness balances the miso's depth), for certain noodle broths, and for the robust preparations of rural Japanese cooking where delicacy is not the primary value. It is categorically not appropriate for chawanmushi or delicate clear soups.
- **Niboshi preparation:** Remove the heads and black entrails from each fish before use — the head and intestines contain bitter compounds that overwhelm the dashi if included. [VERIFY] Tsuji's specification on head/entrail removal. - **The cold soak:** Cleaned niboshi in cold water for 30 minutes to 1 hour before heating — this pre-extraction produces a smoother, less bitter result. - **The heating:** Bring slowly to a near-simmer, skim any foam, hold at 80°C for 5–10 minutes. Do not boil — prolonged boiling extracts the maximum bitter compounds from the remaining fish oil and increases the dashi's fishiness beyond usable levels. - **Straining:** Through a fine cloth to remove all fish particles. - **Flavour profile:** The niboshi dashi's inosinic acid (IMP) content is high but so is its bitter compound content — it requires pairing with bold-flavoured ingredients to balance it.
Tsuji