How to build a rempah properly

Rempah is the aromatic paste that most Malaysian cooking is built on. Shallots, garlic, ginger, often galangal, lemongrass, turmeric, dried chillies, sometimes candlenut, frequently belacan. Blend, fry, add the rest of the dish.

Written like that it sounds trivial, and that is exactly why so many home versions taste thin. The ingredient list is the easy part. What separates a curry that tastes like a restaurant's from one that tastes like a home approximation is almost entirely in the frying, and specifically in how long you are willing to stand there.

Pounding against blending

A batu lesung, the stone mortar, does something a blender does not. Pounding bruises and crushes, rupturing cell walls slowly and releasing aromatic oils as it goes. A blender cuts. The pieces get smaller but they are sliced rather than crushed, and you almost always have to add water to get the blades moving.

That water is the problem. Every spoonful you add is a spoonful you then have to cook off in the pan, and until it has gone the rempah cannot start to fry.

Is pounding worth it? For a small batch, honestly yes, and the difference is real. For a large batch on a weeknight, a blender is fine and everybody uses one. Two things make the blended version much better:

• Use oil instead of water to get the blades moving. It has to go in eventually anyway.
• Blend in stages rather than all at once, hardest things first.

Why order matters

Throwing everything in together produces an uneven paste: the shallots liquefy while the lemongrass is still in shreds, and fibrous pieces survive intact into the finished dish where you find them later.

Work from hardest to softest.

First, the tough aromatics: lemongrass, galangal, turmeric root. These need the most work and nothing else should be cushioning them.

Then ginger, candlenut and rehydrated dried chillies. Candlenut breaks down into a natural thickener, which is much of what it is there for.

Last, shallots and garlic. They collapse almost immediately and adding them early just turns the whole thing to liquid.

Belacan goes in near the end, toasted first. It needs no grinding to speak of.

The part that actually matters

Here is the step. Everything before it is preparation.

The rempah goes into a generous amount of oil over medium heat, and it stays there until it is properly cooked. Not warmed. Not softened. Cooked, which takes considerably longer than most recipes admit.

What happens across that time, roughly in order:

• The paste loosens and bubbles as its water content boils off
• It thickens and starts to catch on the pan, needing more frequent stirring
• The colour deepens, from bright to darker and duller
• The raw sharpness in the smell fades and is replaced by something rounder
• Oil begins to separate out and pool at the edges

That last one is pecah minyak, the oil splitting. It is the signal. When you can see oil sitting distinctly around the paste rather than mixed into it, the water is gone and the rempah is done.

What undercooking tastes like

Sharp and slightly raw, with the shallot and garlic still announcing themselves individually instead of having merged into a base. The dish tastes like a list of its ingredients rather than one thing.

It also will not thicken properly, and no amount of simmering afterwards fixes it, because the problem is not liquid volume. The paste never got the chance to develop.

You cannot rescue it later. This is worth knowing because it means the twenty minutes is not optional time, it is the time when the dish is actually made.

Heat management

Medium, and lower it if things are catching. High heat browns the shallots and garlic before the water has left, which gives you a bitter edge underneath everything.

The paste will stick as it thickens. That is expected. Keep it moving, and if the base starts to darken faster than the rest, take the pan off the heat for a moment rather than adding water. Adding water restarts the whole process you have been waiting to finish.

Making it in batches

Rempah freezes very well, and fried rempah freezes better than raw. Make three or four times what you need, fry the lot properly, cool it, and freeze in portions.

It is the single best thing you can do for weeknight cooking. A curry from frozen fried rempah is twenty minutes of work rather than an hour, and it tastes like the long version, because the long version already happened.

Ice cube trays for portioning, then into a bag. Roughly two cubes per person is a reasonable starting point, adjusted once you know your own paste.

One more thing

Every family's rempah is slightly different, and the variations are not mistakes. Some households use more candlenut for body, some skip galangal entirely, some brown their shallots first for sweetness.

What does not vary is the frying. Every good cook you watch will stand at that pan longer than you expect, and that is the technique, not the recipe.