Asam gelugur
Also known as asam gelugor, asam keping, gelugor, som khaek, Garcinia atroviridis
Quick answer
The fruit of a Garcinia tree of the Malay Peninsula, picked full-grown but still green, sliced and dried, and boiled with fish, curries and relishes to sour them. It is the asam keping of Malaysian shops, and a relative of kokum and kudampuli, not of tamarind.
- Tastes of
- sour
- Heat
- Scoville does not apply
- If you have none
- Tamarind — see the limits
Other names
What this spice is called elsewhere, and where the translation is not clean.
asam gelugor
Malay
Asam is the Malay word for sour and is used for several souring agents. Asam jawa is tamarind, an unrelated plant.
asam keping
Malay
The name of the dried slices as sold, not of the tree or the fresh fruit.
som khaek
Thai
Flavour and aroma
Sour, and strongly so. The handbook calls the dried fruit a seasoning or sour relish, and the review says the slices are used to give acidity to cooked food. Fresh fruit bought in North Sumatra measured between pH 1.7 and 1.8, the unripe fruit a little more acid than the ripe. Stewed with a great deal of sugar, the handbook adds, the fruit is excellent to eat.
The pH is of fresh fruit from one farm, in one small study.
The fresh fruit is green when it is picked and bright orange-yellow when ripe.
The sources describe the fresh fruit. None read here describes the colour of the dried slices.
Taste, smell and sensation, channel by channel
Smell, taste and the chemical sense of heat and cold are different senses. Each is listed with the compounds evidenced as producing it.
Taste
- Sour
Sourness is what it is cooked with for. Fresh fruit from one farm in North Sumatra measured pH 1.7 to 1.8, and a Thai curry paste made with the dried fruit stood at pH 3.4 against 5.1 for the same paste without it. A review names hydroxycitric acid as the main acid of the fruit; no measurement of the acids was read, so no compound is linked here.
Heat
Pungency scale: none — this spice is not pungent
No heat.
Pairings
Ranked by how well established the combination is, with the reason and the caveats attached.
Other spices and blends
Lemongrass
ClassicThe two go into the pot together in the Malaysian fish dishes a food-consumption survey describes: masak singgang is seafood boiled with asam gelugur and lemongrass, and masak lemak adds both to coconut milk with basil and turmeric leaf. The dried fruit supplies the sourness and the lemongrass the scent.
How: Masak singgang; Masak lemak
The survey describes each dish in a line and gives no quantities.
Turmeric
ClassicThe southern sour curry of Thailand is built on a paste of fresh turmeric, garlic, shallot and chilli, and is then soured, with lime juice, tamarind or the dried fruit. The turmeric gives the curry its yellow and the fruit its acid: in one study a paste made with the dried fruit stood at pH 3.4 against 5.1 without it. In Peninsular Malaysia the same fruit is boiled with fish in coconut milk with turmeric leaf.
How: Southern Thai sour curry; Masak lemak
Add alongside: Garlic, Lemongrass
The Thai study prints the name of the curry as Keang-hleung. The Malaysian dish uses the leaf of the turmeric plant, not the rhizome.
If you have no asam gelugur
What to use instead, and — more usefully — where each replacement stops working.
Tamarind
AcceptableSours the dish with a different fruit. The handbook account of Garcinia records that its sour fruits are sometimes used as substitutes for tamarind, so the two are known to stand in for each other; nothing read compares them in a dish, and the Malaysian survey read for the profile shows cooks using each in different dishes.
| Flavour | Aroma | Colour | Heat |
|---|---|---|---|
| partial | different | different | n/a |
Works for
- A sour fish dish when the dried slices cannot be found
Does not work for
- A dish named for asam gelugur, where a reader expects that fruit and not tamarind.
No ratio is given: no source read states one, and the two differ in form, one a dried slice left in the pot and the other a pulp.
Preparation and use
Add the dried slices to the pot with the liquid and boil them with the dish, as the Malaysian fish dishes recorded here do. The sources read do not give quantities.
A souring agent. The handbook records the dried fruit as a seasoning or sour relish, and a review as a seasoning for curries, sour relishes and fish dressings. In Peninsular Malaysia it is boiled with fish and seafood in masak lemak, singgang and rebus. In southern Thailand it is one of the things that sour the yellow sour curry, ground into the paste or added to the pot. The handbook adds that the fruit is stewed with sugar, and that the dried fruit is used to fix dyes.
- boiling — In the dishes a Malaysian food survey describes, the dried fruit is boiled with the fish: in coconut milk with lemongrass and turmeric leaf, with lemongrass alone, or with onion and salt.
- grinding — Ground into a curry paste, the dried fruit carries its acid into the paste. A southern Thai sour curry paste of turmeric, garlic, shallot and chilli stood at pH 5.1; the same paste made with the dried fruit stood at pH 3.4, with more than three times the titratable acidity.
The paste figures are from one formulation in one storage study.
Storage and freshness
| Form | Good for | Conditions | Fridge |
|---|---|---|---|
| Dried whole | Not established | Cool, dry and closed. | — |
Soak a slice in a little warm water and taste the water. It should be plainly sour.
- Visible mould
- A musty smell
- Moisture uptake, leading to mould in humid conditions
Quality is not the same as safety
Slices that have lost their sourness are a matter of quality. Mouldy slices should be thrown away.
Forms
The form the sources describe, and so the one this page is about.
Dried slices (asam keping)
Thin slices of the whole green fruit, dried in the sun. This is the form sold and the form the recorded dishes use.
Put the slices in the pot with the liquid and boil them with the dish.
The survey describes each dish as seafood boiled with the dried fruit. It does not say how many slices, or whether they are taken out.
Botany
The handbook gives the name as published in the Flora of British India in 1874 and lists no synonym for it.
Clusiaceae
The handbook uses the older family name, Guttiferae; the review gives both. It is the mangosteen family, shared with kokum and kudampuli.
The fruit, picked full-grown but green and dried whole or in slices. The young shoots and leaves are eaten as a sour vegetable, which is a different use of the tree.
An evergreen tree up to 20 m tall with drooping twigs and leaves, smooth pale grey bark and colourless latex. The leaves are narrowly oblong, up to 20 cm long and occasionally 30, dark green, glossy and leathery, and bright red when young. The fruit is round, 7–10 cm across, with 12–16 grooves running from top to bottom and a thin, smooth skin that turns bright orange-yellow; inside are a few flattened seeds, or none, in bright orange pulp. The tree usually bears female flowers only, and male flowers are uncommon.
Commonly confused with
An unrelated legume that shares the word asam. In a survey of Malaysian fish cooking the two are used in different dishes: tamarind paste in masak sambal and asam pedas, asam gelugur in masak lemak, singgang and rebus. The handbook notes that sour Garcinia fruits are sometimes used as substitutes for tamarind.
Garcinia gummi-gutta of Kerala and Sri Lanka, the same genus doing the same job. Kudampuli is the rind alone, dried over smoke until black; asam gelugur is the whole green fruit, sliced and dried in the sun, with no smoke.
Garcinia indica of the Konkan coast, the third souring fruit of the genus held here, and the dried rind of a ripe purple fruit.
How it is grown
The plant, how it is propagated and farmed, what threatens the crop, and where it is produced now. Crop diseases here are plant health, not food safety.
The whole fruit, round, 7–10 cm across and grooved from top to bottom, picked when full-grown but still green and dried whole or in slices.
How it is propagated
- Seed.
The species of the genus are usually raised from seed. Many of them can set seed without fertilisation, and this one usually bears female flowers only, male flowers being uncommon.
- Grafting.
Occasionally grafted, as the handbook says of the genus; it gives no method for this species.
The tree can set fruit and seed without being pollinated. The handbook notes that it usually bears female flowers only, male flowers being uncommon. In an orchard in Songkhla, southern Thailand, flowers bagged and left unpollinated still bore fruit, though fewer and smaller, with fewer seeds that germinated less well than those of open-pollinated or hand-pollinated flowers. Among seedlings from open-pollinated fruit, 58 per cent on average were genetically identical to the mother tree, the share ranging from 36 to 87 per cent, and the rest showed that fertilisation had taken place. The authors call this facultative apomixis: seed is formed both ways, and pollination still matters to the size of the crop.
Native to Peninsular Malaysia, Thailand, Burma and Assam, and cultivated in the same places as a home-garden tree. The handbook says that only the mangosteen, of the genus, is cultivated on a commercial scale.
Where it comes from and how it is made
Native to Peninsular Malaysia, Thailand, Burma and Assam in India, and cultivated in the same places.
- Malaysia (Peninsular Malaysia) — native range. Native, and grown in gardens; the dried slices are sold there as asam keping.
- Thailand — native range. Native, and described in a review as broadly cultivated in the south. A Thai study calls it a local fruit of the south and bought the dried fruit in a market in Hat Yai.
- Indonesia (North Sumatra) — notable producer. A drying study bought its fruit from a farmer at Sembahe in Deli Serdang, and describes the tree in Indonesia as half-wild. The handbook lists the Malay names for Indonesia but does not include Sumatra in the native range.
- Myanmar — native range. Native, and described in the same review as broadly cultivated.
Where the tree grows. No figure for how much is produced was read.
The fruit is taken when it is full-grown but still green, before it turns orange-yellow.
- Picking green — Full-grown fruit is picked while it is still green.
- Slicing — The fruit is cut into thin slices. The handbook says it is also dried whole.
- Sun-drying — The slices are dried in the sun and sold as asam keping. In Malaysia they are traditionally laid on mats in the open, directly under the sun.Why: The fresh fruit is about nine-tenths water, and it is the dried slice that keeps and is sold.
The sources give the steps in a sentence or two each. None says how long drying in the sun takes.
A home-garden tree. The handbook says that only the mangosteen, of all the genus, is cultivated on a commercial scale, and that some of the wild species are grown in gardens.
A tree of the humid tropics. The handbook describes the wild species of the genus as second-storey forest trees adapted to shade; the review places this one in humid mixed lowland forest and up to 600 m in the high-rainfall highlands.
How these steps work: sun drying.
What processing and storage do to it, as measured
Drying
The fruit is dried to be used as a seasoning, and the dried slices are the asam keping of the market. The traditional way is to lay the material on mats in an open space, directly under the sun. Engineers describing it name its weakness as the weather: the quality of what is dried cannot be controlled, because the drying depends on the conditions of the day.
Conditions: in air · Slices laid on mats in the open, directly under the sun, as described for Malaysia
What this does not show: A description in a few sentences by authors whose subject was their own dryer. It gives no drying time, no slice thickness and no account of how producers judge that the slices are dry.
Documented practice
Drying · Depends on conditions moisture
How dry the slices came out depended on how ripe the fruit was as well as on how long it was dried. Averaged over the three drying times, slices from unripe fruit held 13.8 per cent water, from half-ripe fruit 16.2 per cent and from ripe fruit 19.9 per cent. Averaged over ripeness, 12 hours left 19.0 per cent, 13 hours 16.5 per cent and 14 hours 14.4 per cent. The fresh fruit itself differed little, at 89 to 90 per cent water, but the ripe fruit was heavier, sweeter and slightly less acid, at pH 1.80 against 1.67. The authors judged unripe fruit dried for 12 hours the most acceptable.
Conditions: in air · 50 °C in a cabinet drier · 12, 13 and 14 hours · Slabs about 5 mm thick, cut from unripe, half-ripe and ripe fruit
It agrees with the practice the handbook records, of picking the fruit full-grown but still green for drying.
What this does not show: A short conference paper on fruit from one farm, dried in a cabinet and not in the sun. It does not say how acceptability was judged, and its figure for the acid content of the fruit is not used because it does not agree with its own water content.
Measured on the spice
Buying and quality
- Sold as asam keping or asam gelugur. Asam on its own may mean tamarind.
- Dry slices with no mould and no musty smell.
Physical properties and standards
Moisture, water activity, ash, volatile oil and the like — what standards require kept apart from what has been measured.
| Property | Value | Sample and method |
|---|---|---|
| Moisture (fresh) | 89–90.3 % | Fruit from one farm at Sembahe, Deli Serdang, North Sumatra, weighing 339 to 448 g and 9.0 to 10.2 cm across · Water content of the fresh fruit by the oven method, at three stages of ripeness; a second study gives 90 per cent, wet basis, for the fruit it dried |
| Moisture (dried whole) | 13.8–19.9 % | Slabs about 5 mm thick from unripe, half-ripe and ripe fruit, dried in a cabinet drier at 50 °C for 12, 13 and 14 hours · Mean water content of dried slices by ripeness of the fruit and by drying time; unripe fruit and longer drying gave the drier slices |
| Moisture (dried whole) | 4.4 % | One batch dried in an experimental solar dryer in Malaysia · Final water content of the fruit after drying in a portable solar dryer; the Malay abstract gives 4.44 per cent, and a market sample dried the traditional way measured 4.54 per cent |
A limit is set by a rule of one kind, in one place; a measurement describes particular samples. Neither is a property of every jar.
History and trade
The handbook says that, apart from the mangosteen, the fruits of the genus are traded only locally. A review of 2022 describes the dried slices as sold commercially in the region, and som khaek as increasingly sold in Thailand as capsules, slices and tea.
No trade figure was read.
Claims we do not accept at face value
“Asam gelugur is a kind of tamarind.”
popular but unsupported
The shared word is asam, which means sour. Tamarind is the pod of a legume, Tamarindus indica; asam gelugur is the fruit of a Garcinia, in the mangosteen family. The handbook records sour Garcinia fruits as substitutes for tamarind, which is how the two come to share a shelf.
Culture
Recorded by tradition rather than merged into one narrative — these are genuinely different practices.
Peninsular Malaysia
A survey of what 2,675 adults ate over three days in 2008 and 2009 describes three ways of cooking fish and seafood with the dried fruit: masak lemak, boiled in coconut milk with lemongrass, basil and turmeric leaf, in 320 of the records; masak singgang, boiled with asam gelugur and lemongrass, in 158; and rebus, boiled with onion, salt and asam gelugur, in 67. Tamarind paste is named for two other dishes in the same table. The young shoots and leaves of the tree are eaten raw or cooked as ulam.
- Masak lemak
- Masak singgang
- Rebus
Southern Thailand
Known as som khaek and broadly cultivated in the south, where a Thai study calls it a local fruit. The same study describes the southern sour curry, which it writes as Keang-hleung: a soup of vegetables on a paste of fresh turmeric, garlic, shallot and chilli, yellow from the turmeric and soured with lime juice, tamarind, this fruit or whatever sour fruit is to hand. Its authors bought the dried fruit in a market in Hat Yai and ground it into the paste. An earlier study by the same group made a dried tom yum seasoning mix soured with the fruit.
The curry is documented as soured with this fruit among others. The tom yum mix was an experimental product, and the abstract read does not say the fruit is customary in that soup.
- Southern sour curry
- Dried fruit ground into curry paste
North Sumatra
North Sumatra, Indonesia.
A food-science paper from Medan says the fruit has been used in Indonesia as a seasoning and for tea, and names one dish, which it writes as Asam Padeh, as an example. It bought its fruit from a farmer in Deli Serdang and dried it in slices.
One sentence in one short paper, which names the dish and does not describe it. No cookery source for Sumatra was read.
- Dried slices as a seasoning
Also documented in North Sumatra: Andaliman.
What it is called
- Malay: asam keping
- Thai: som khaek
What we do not know
Published openly. A gap we have named is more useful than a gap we have filled with plausible prose.
Not yet established for asam gelugur:
- Archaeological evidence
- Historical timeline
- Ceremonial use
- Traditional medicinal context
- Regulatory limits
- Traditional uses