Aromatic bases & spice pastes
Iru
Iru · A fermented seed condiment made from the seeds of the African locust bean tree (Parkia biglobosa), produced by a natural Bacillus subtilis fermentation. It functions as a potent umami seasoning and foundational aromatic base used across West African cuisines.
The formula
Seeds fully covered by water; salt to taste for storage (no fixed weight ratio)
Traditional preparation is by feel, not measure. Beans are boiled until soft, dehulled by hand, then packed and left to ferment 2–5 days; salt is added only at the storage stage.
Identity
- Fermented seed condiment (not a paste or sauce)
- Solid, chunky texture with soft individual cotyledons
- Powerful pungent aroma; deeply savory, meaty umami
- Naturally preserved by fermentation and salt
- Made from Parkia biglobosa seeds as the canonical ingredient
- Used as a reusable aromatic seasoning across West African soups and stews
Ingredients
| Base | African locust bean seeds (Parkia biglobosa) | The defining ingredient; mature dried seeds are harvested from long pods, then boiled and dehulled before fermentation. |
| Liquid | Water | Used for boiling the seeds to soften them for dehulling; the cooked seeds are then drained and fermented in their own moisture. |
| Seasoning | Salt | Added after fermentation primarily for shelf stability and storage — not part of the fermentation itself. |
Method
- 1Boil dried Parkia biglobosa seeds in water until soft enough to crush between the fingers.The hard seed coat must be softened so the hulls can be removed cleanly by hand without damaging the cotyledon.
- 2Drain, cool slightly, and rub the seeds between palms or against a sieve to remove the dark seed coats; rinse to recover clean cotyledons.Dehulling removes bitter, fibrous hulls and exposes the starchy cotyledons that will carry the fermentation.
- 3Pack the dehulled, drained beans loosely into clean containers, banana leaves, or wrapped bundles; press down lightly and leave to ferment at ambient temperature.Anaerobic conditions favor Bacillus subtilis naturally present on the seed surface; the bacteria convert proteins and starches into free amino acids and aroma compounds over 2–5 days.
- 4Wait until the ferment develops its characteristic pungent, ammonia-edged aroma and a soft sticky texture binding the beans together.Time allows the microbial succession (mainly Bacillus subtilis) to produce the signature umami and sulfurous notes.
- 5Salt the finished ferment generously and portion it — keep wet iru refrigerated or sun-dry into dry iru cakes for shelf storage.Salting and drying are the traditional ways to stabilize the product against spoilage after fermentation is complete.
Techniques that matter
Boil-and-rub dehulling
The seed coat of Parkia biglobosa is too tough to remove raw; boiling softens it so it sloughs off cleanly during hand-rubbing.
Ambient solid-state fermentation
Wild Bacillus subtilis on the seed surface drives a natural fermentation in packed, drained beans — no starter culture is required.
Press-pack fermenting in banana leaves
Traditional wrapping creates mild anaerobic conditions and contributes subtle aroma while keeping the ferment moist.
Variations & derivatives
DawadawaNorthern Nigeria / Hausa
Same Parkia biglobosa fermentation, often pressed into balls and sun-dried for trade.
Soumbala / NététouFrancophone West Africa (Mali, Burkina Faso, Senegal)
Same condiment under French and Wolof names; widely used as a Maggi-style seasoning cube substitute.
AfitinBenin
Very close relative of iru/dawadawa made from African locust beans or soybeans.
OgiriIgbo (Southeastern Nigeria)
Often made from castor seeds or melon seeds rather than locust beans, but performs a similar seasoning role.
Soybean iruModern urban Nigeria
Soybeans are sometimes substituted for locust beans because they are cheaper and easier to dehull, producing a milder but similar condiment.
Used in these dishes
Substitutions
- Parkia biglobosa seeds → Soybeans — Soybeans ferment similarly and produce a comparable (milder) umami condiment; widely used as a practical substitute.
- Iru / dawadawa → Ogiri — Different seed (castor or melon) but provides the same pungent, savory seasoning function in soups.
- Iru / dawadawa → Stock plus miso or fermented soybean paste — In extremis, a combination of strong stock and a fermented soybean paste can mimic the umami depth, but the aroma profile will be very different.changes result
Troubleshooting
Ferment smells rotten or fecal rather than pungent-savoury
Contamination by spoilage anaerobes — too wet, too tightly packed, or too long at ambient temperature → Discard; next batch, drain beans thoroughly after boiling and pack loosely so gas can escape during the early fermentation.
Beans turn very dark, mushy, or slimy during ferment
Over-fermentation or excess moisture allowing non-Bacillus microbes to dominate → Shorten fermentation to 2 days and reduce residual cooking water before packing.
Weak aroma and bland flavor after fermentation
Old or poorly stored dried beans with low viable Bacillus population, or fermentation too short → Use fresher seed stock and ferment at warm ambient temperature for a full 3–5 days; ensure beans stay moist but not submerged.
Wet iru spoils within a few days even when refrigerated
Insufficient salting at the storage stage → Salt more generously and keep submerged in a little brine in a sealed container.