Rempah is the pounded spice paste that forms the foundation of Malay, Peranakan, and Singaporean cooking. Like Thai curry paste, it's built through deliberate pounding rather than blending. Unlike Thai paste, rempah typically includes belachan (fermented shrimp paste), candlenuts (for body and creaminess), and turmeric alongside the aromatics. The paste is then fried in oil for an extended period — 20-30 minutes — until the oil separates, a process called 'tumis' that is the defining technique of the cuisine.
Hard ingredients first in the mortar: dried spices, candlenuts, galangal. Then softer: lemongrass, fresh turmeric, chillies, shallots, garlic. Belachan (toasted first over flame until crumbly and fragrant) goes in last. The paste must be fine and smooth. Tumis: fry the paste in generous oil over medium heat, stirring constantly, for 20-30 minutes. The oil will gradually separate and pool — this is the signal that the paste is cooked. If you stop before the oil separates, the dish tastes raw and harsh.
The colour of the oil tells you when it's done — it takes on the colour of the paste (red for chilli-based, yellow for turmeric-based). For laksa: the rempah includes dried shrimp, galangal, lemongrass, fresh and dried chillies, and belachan — fried until the kitchen is foggy with aromatic steam. This is the foundation that makes laksa impossible to replicate from a jar. Freeze extra rempah in portions — it freezes perfectly.
Not frying the rempah long enough — the oil MUST separate. Using a blender without enough oil — produces a watery paste that spatters dangerously. Not toasting the belachan first. Rushing the tumis — you cannot shortcut it. Skipping candlenuts — they provide the velvety body unique to Malay curries.