Spices in Indonesian cooking

Turmeric gives chicken the golden colour that a great many South and Southeast Asian dishes depend on visually, alongside an earthy base note. It is used in small quantities — enough for colour, not enough for bitterness.

Add alongside: Cumin, Coriander seed, Ginger

• More than about a teaspoon in a family-sized dish turns the flavour bitter without adding useful colour.

Widely used in South and Southeast Asian fish cooking for colour and a mild earthiness, and traditionally rubbed on before frying.

Add alongside: Cayenne pepper, Coriander seed

• Use sparingly; turmeric's bitterness is more noticeable against delicate fish than against meat.

The sour-sweet base of pad thai and of Malay and South Indian prawn dishes. Prawns are sweet and faintly mineral, and tamarind meets that sweetness rather than fighting it — the reason a sour prawn dish tastes balanced where a sour chicken one often does not.

How: In the sauce for pad thai, with fish sauce and palm sugar; In a Malay-style sour prawn curry

Add alongside: Chilli flakes, Coriander seed, Turmeric

Sour fish curries run from Kerala to Malaysia to Indonesia, and tamarind is the souring agent in most of them. Acid firms the flesh slightly and cuts the oiliness, and the fruit body gives the sauce a depth that lime alone cannot.

How: In a Keralan or Goan fish curry; In a Malay-style sour fish soup

Add alongside: Turmeric, Fenugreek, Mustard seed

• Add it before the fish rather than after — the acid needs time in the sauce, and the fish does not want the extra cooking.

Tom yum and the Malay sour prawn curries both run on it. Prawns are sweet and faintly mineral, and galangal’s pine-and-citrus sharpness cuts that sweetness in a way ginger cannot — ginger would meet the sweetness and compound it.

How: Sliced into a tom yum broth; Pounded into a paste for a prawn curry

Add alongside: Lemongrass, Chilli flakes, Tamarind

Tom kha gai is the dish most people meet galangal in, and the pairing is doing structural work: chicken and coconut milk together are rich and mild, and galangal supplies the sharp resinous note that stops the soup tasting flat. Left out, the dish is coconut chicken soup.

How: Sliced into a coconut and chicken soup; In a curry paste for a chicken curry

Add alongside: Lemongrass, Coriander seed, Turmeric

• Add the slices early — the aromatics disperse into the broth within minutes and the slices are not meant to be eaten.

Rendang and the Indonesian slow braises, where galangal survives hours of cooking better than most aromatics and keeps giving a resinous edge against a very rich coconut and beef base.

How: Pounded into a rempah for rendang; In a long-braised curry base

Add alongside: Turmeric, Coriander seed, Chilli flakes

Documented across Thai, Vietnamese and Malay cooking, and it works because lemongrass gives citrus aroma without acidity. Lemon juice on chicken firms the surface and changes the texture; lemongrass gives the same bright register with none of that, which is why it can go into a marinade for hours or into a broth for minutes and do no harm either way.

How: Pounded to a paste with garlic and chilli as a marinade for grilled chicken; Bruised stalks in a poaching broth, removed before serving

Add alongside: Garlic, Galangal, Turmeric

• Only the pale lower stem is worth using; the dry upper leaf gives fibre and very little aroma.

A delicate fish is the case where lemongrass has the clearest advantage over lemon: it perfumes without acidifying, so the flesh stays soft. Steaming or grilling in a leaf parcel with bruised stalks underneath is the standard Southeast Asian treatment and puts the aroma into the fish without any liquid at all.

How: Bruised stalks laid under a whole fish for steaming or grilling; In a coconut broth for poached fish

Add alongside: Galangal, Turmeric, Coriander leaf

• Long boiling drives off the fresh top note and leaves the duller, more resinous part behind.

The defining aromatic pair of Thai cooking, and they are partners precisely because they share nothing: lemongrass is citric from citral, galangal piney and camphorous from cineole. Neither substitutes for the other and a paste built on one alone is recognisably missing an axis. Recording the pair is the useful correction to the widespread assumption that they are two versions of the same thing.

How: Both pounded into a curry paste; Both bruised into a tom kha or tom yum broth

Add alongside: Turmeric, Chilli flakes, Garlic

Documented across Thai, Malay and Vietnamese cooking, and the reason is that prawn sweetness needs a sharp rather than a broad heat. Bird's eye arrives immediately and clears, so it cuts through without sitting on the palate for the next mouthful — the opposite of what a superhot would do to a delicate shellfish.

How: Pounded with garlic and lime into a dipping sauce for grilled prawns; Sliced raw into a warm prawn salad

Add alongside: Lemongrass, Garlic, Lemon

• Pounding spreads the placental heat through the whole sauce, so a pounded dressing eats considerably hotter than the same pods sliced.

Documented across Thai, Malay and Indonesian cooking, and the mechanism is the one that makes this leaf worth having: it supplies lime aroma without acidity. Chicken takes citrus well and firms unpleasantly under acid, so a marinade or a broth flavoured with the leaf gets the fragrance of lime peel while the texture is untouched.

How: Torn into a coconut chicken curry and removed before serving; Pounded into a curry paste with lemongrass and galangal

Add alongside: Lemongrass, Galangal, Garlic

• Tear the leaves. An intact leaf dropped into a pot releases very little, because the oil is inside the tissue rather than on the surface.

Tom yum is the documented case and it shows the division of labour clearly: the leaf supplies aroma and the lime juice supplies sourness, and cooks who assume the leaf is doing both end up with a broth that smells right and tastes flat. Prawns are sweet and faintly iodic and take the sharp citrus-floral note particularly well.

How: Torn into a tom yum broth with lemongrass and galangal; Shredded very finely through a warm prawn salad

Add alongside: Lemongrass, Galangal, Bird's eye chilli

• Shredded leaf must be cut very finely across the grain with the rib removed, or it stays tough and fibrous in the mouth.

Rendang is the case, and the pairing works because a long-cooked rich beef dish needs an aromatic that survives hours of cooking without turning bitter. The leaf is thick and leathery and gives up its oil slowly, so it holds its character through a reduction that would destroy a soft herb entirely.

How: Whole leaves through a rendang, cooked down with coconut and spice paste; In a Thai beef salad, shredded raw at the end

Add alongside: Lemongrass, Galangal, Turmeric

The one pairing in this dataset where the mechanism is not an analogy. Pandan’s dominant aroma compound, 2-acetyl-1-pyrroline, is the same compound that gives basmati and jasmine rice their scent, and it is present in the leaf at far higher concentration. A knotted leaf in the pot therefore does not merely sit alongside the rice — it supplies more of exactly what fragrant rice already smells of, which is why ordinary long-grain rice cooked with pandan reads as a better grade of rice.

How: A knotted leaf cooked in the rice pot and removed before serving; In coconut rice and nasi lemak

Add alongside: Lemongrass, Curry leaf

• Knot the leaf. An intact leaf laid in whole releases very little, because the aroma is held in cells that need rupturing.

Pandan is the default sweet aromatic of Southeast Asia, occupying the position vanilla holds in European baking, and its natural partner is palm sugar. The pairing carries the whole family of kuih, the coconut jam kaya, and most of the region’s syrups and cold drinks. The leaf’s grassiness keeps a heavily sweetened preparation from cloying, which is the work it is actually doing.

How: Steeped into palm sugar syrup; Blended and strained into kuih and cake batters; In kaya, the coconut and egg jam

Add alongside: Vanilla, Green cardamom