Spices in Thai cooking

Coriander's citrus lift brightens pork's richness and bridges between cumin and the sweeter spices. It is a rounding presence rather than a lead flavour here.

Add alongside: Cumin, Black pepper

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.

Coriander's citric sweetness suits chicken particularly well and gives body to a sauce without weight. It is the quiet component that makes a chicken curry taste finished.

Add alongside: Cumin, Turmeric, Green cardamom

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.

Standard across coastal South Asian cooking, where prawns are turned in turmeric and salt before they meet anything else. It colours them and takes the edge off the iodine note that large prawns can carry.

Add alongside: Garlic, Chilli powder, Lemon

• Turmeric is bitter in quantity and prawns are delicate. A quarter teaspoon for a plateful, not a spoonful.

Ginger's sharpness is the corrective a sweet squash needs, in soup as much as in pie. It is the component of a pumpkin spice blend doing the most work and the one most obviously missed when it is left out.

Add alongside: Cassia, Nutmeg, Allspice

The base of most curry powders. Turmeric contributes colour and a bitter earthiness, cumin contributes aroma; neither does the other's job. Turmeric is used in much smaller quantity than its visual prominence suggests.

Add alongside: Coriander seed, Cayenne pepper

The most widely used aromatic pair in the world, and in South Asian cooking often literally one ingredient — ginger-garlic paste, pounded together and used as the base of an enormous range of dishes. Ginger is sharp and citric where garlic is sulphurous and sweet, and each covers what the other lacks.

How: Pounded together into ginger-garlic paste; Sliced or minced and fried at the start of a stir-fry

Add alongside: Onion, Chilli powder, Turmeric

• Both burn quickly and bitterly in hot fat. They go in after the pan has come off the fiercest heat, not before.
• This is a fresh-ginger pairing. Ground ginger and garlic powder are not the same combination and do not behave the same way.

A standard of Chinese and Japanese fish cookery. Ginger is used specifically to counter the smell of fish — an explicit purpose in the culinary literature rather than an incidental effect — and its citric sharpness cuts the oiliness of salmon at the same time.

How: Julienned with spring onion over steamed fish; In a soy and rice wine marinade

Add alongside: Onion, White pepper, Fennel seed

• Fresh ginger only. Ground ginger against salmon tastes of baking spice and is a well-known way to spoil a good fillet.

Two different kinds of heat used together deliberately. Ginger is pungent at the back of the throat and citric on top; chilli is pungent on the tongue and fruity behind. Neither masks the other, which is why South and Southeast Asian cooking uses both rather than choosing.

Add alongside: Garlic, Turmeric, Coriander seed

• Both are pungent and the effects add rather than cancel. A dish adjusted for one before adding the other will usually end up too hot.

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.

Recorded because it is the technique rather than a flavour affinity. Tamarind carries a great deal of acid and a great deal of sugar at once, and nearly every dish built on it adds more sweetness — jaggery in sambar, palm sugar in pad thai, jaggery and dates in imli chutney. The practical consequence is that a dish tasting harshly sour usually needs sugar rather than less tamarind, which is the opposite of the instinct.

How: Jaggery melted into a tamarind-soured dal; Palm sugar in a pad thai sauce

Add alongside: Chilli flakes, Cumin, Ginger

Aubergine is rich and absorbent and turns heavy without an acid to cut it. Tamarind does that job across South Indian and Southeast Asian cooking, and unlike citrus it survives the long cooking aubergine needs.

How: In a South Indian aubergine and tamarind curry; In a sweet-sour braise with jaggery

Add alongside: Mustard seed, Fenugreek, Chilli flakes

Heat against sweetness is one of the most reliable pairings there is, and sweet potato is sweet enough to take a good deal of it. Chilli also gives the dish somewhere to go: a plain roast sweet potato is one-note in a way few vegetables are.

How: On roast wedges with lime; In a sweet potato and coconut curry

Add alongside: Cumin, Lemon, Garlic

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

Mushrooms are earthy and slightly sweet and take sharp aromatics well. In a Thai hot-and-sour soup the galangal and the mushroom do opposite jobs and the dish needs both.

How: In a hot-and-sour mushroom soup; Sliced into a braise

Add alongside: Lemongrass, White pepper, 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.

Tom yum is the documented case and the mechanism generalises: prawns are sweet and faintly iodic, and the citral in lemongrass cuts both without adding the acid that would start cooking them. In a hot-and-sour broth it is the aromatic doing the lifting while lime juice does the souring — the two are usually assumed to be one thing and are not.

How: Bruised stalks simmered in the broth with galangal and lime leaf; Finely sliced raw through a warm prawn salad

Add alongside: Galangal, Chilli flakes, Coriander leaf

• Sliced raw it must be cut very thinly across the grain, or the fibres are unpleasant to eat.

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

The standing use across East and Southeast Asian home cooking, where chicken powder — MSG with salt and chicken extract — is a pantry staple. Chicken is mild and takes savoury depth without a competing flavour, which is exactly the case MSG suits: it makes the stock taste longer-simmered without introducing anything identifiable.

How: Dissolved into a chicken stock or braise with the salt; In a marinade for fried chicken, alongside salt and pepper

Add alongside: White pepper, Garlic, Ginger

• Add it with the salt rather than instead of it. The two are different tastes and neither reaches the other’s ceiling.

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.

Two separate traditions arrive at the same pairing: Thai grilled and stir-fried chicken with prik kee noo, and Portuguese-African peri-peri chicken made from the same pepper under another name. Chicken is mild enough that the chilli defines the dish, and both traditions use garlic and acid alongside it for the same reason — to carry the heat rather than to temper it.

How: Pounded with garlic and vinegar as a peri-peri marinade for grilled chicken; Sliced into a basil chicken stir-fry at the end

Add alongside: Garlic, Basil, Lemon

• In a marinade the heat penetrates and cannot be removed later, so err low and serve more chilli alongside.

Pad kaphrao is the documented case and the combination is specific: Thai holy basil is peppery and clove-like rather than sweet, and bird's eye supplies a sharp heat that sits beside that pepperiness rather than covering it. The pairing works far less well with the sweet Genovese basil most Western shops sell, which is worth knowing before attempting the dish.

How: Pounded with garlic and fried at the start, with basil thrown in at the end; Both stirred through a finished stir-fry off the heat

Add alongside: Garlic, Lemon

• Holy basil and sweet basil are different plants with different flavours. Substituting one for the other changes the dish more than changing the chilli would.

A lean, delicate fish is exactly where black pepper is too heavy — its roasted, woody depth sits on top of the fish rather than beside it. Green pepper is milder and brighter and adds pungency without weight, which makes it one of the few peppers that suits white fish in any quantity.

How: Crushed into a butter or cream sauce for poached fish; Whole corns in a Thai stir-fry with fish

Add alongside: Dill, Lemon, Lemongrass

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

Thai pandan-wrapped fried chicken is the case where the leaf does structural work rather than being steeped and discarded: it is a parcel and a flavouring at once, holding the marinade against the meat and perfuming it from the outside while the wrapper takes the direct heat. This is close to the only preparation in the dataset where an aromatic leaf is also a cooking vessel.

How: Marinated chicken wrapped in leaves and deep-fried; The leaf discarded at the table rather than eaten

Add alongside: Coriander seed, White pepper, Garlic

• The leaf is not eaten — it is tough and fibrous, and it is opened rather than served whole.