Cooking in
British Columbia
Thai · Southern Thailand
Phrik Gaeng Som — Southern Sour Curry Paste / พริกแกงส้ม
Southern sour curry paste (phrik gaeng som) is one of the most regional and uncompromising of Thai pastes — it uses dried red chillies and fresh turmeric (not kaffir lime rind or galangal) as its defining aromatics, and contains no coconut in its corresponding curry. Fresh turmeric (kamin) is pounded raw into the paste, producing a vivid yellow-orange colour and the characteristically earthy, slightly bitter turmeric flavour that distinguishes gaeng som from all other Thai curries. Kapi content is very high, and dried shrimp may be added. The resulting paste is designed to work with sharp, sour liquid (tamarind water or green mango) rather than coconut cream.
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Cook
I
The Market List
The benchmark for each ingredient, and who stocks it near you. Tap a stockist to go straight to the product.
10–12
Dried red chillies
soaked in warm water until pliable, drained
Not yet stocked in British Columbia
30 g
Fresh turmeric (kamin)
peeled, roughly sliced — wear gloves
Your own market
4
Shallots
charred whole in their skins over a flame or dry pan until blackened outside, then peeled
Your own market
30 g
Kapi (shrimp paste)
wrapped in foil and roasted briefly until fragrant, or used raw if roasting is not specified
Not yet stocked in British Columbia
15 g
Dried shrimp
optional; added where a deeper fermented note is desired
Origin · VietnamChoose your town to see who stocks it →
1 tsp
Salt
Your own market
Each tap is counted, so the stockist sees the demand Provenance sends them.
II
The Method
1
Soak the dried red chillies in warm water until fully pliable, so the flesh softens through to the core and will break down cleanly under the pestle rather than tearing into stringy shreds. Drain and squeeze out excess water. The chillies should be soft with no hard, brittle sections remaining — press one between the fingers to confirm.
2
Char the shallots whole, in their skins, directly over a flame or in a dry pan, turning them until the outer skin is blackened and the flesh inside has softened, so the heat drives a gentle sweetness and a faint smokiness into the flesh that raw shallots cannot give this paste. The skins will blister and pull away easily — this is the Southern Thai technique specific to this paste. Remove the charred outer layers and discard.
3
Pound the drained chillies with the salt in a granite mortar, so the salt acts as an abrasive that helps the fibres break apart faster and more evenly than chillies alone. Work until a coarse, fibrous paste forms with no large chilli pieces remaining — the mass should be an even, deep red and offer only slight resistance to the pestle.
4
Add the sliced fresh turmeric and pound it thoroughly into the chilli base, working until no fibrous threads or raw slices remain and the paste is uniformly yellow-orange, so the sharp, camphor-earth oils locked inside the rhizome are fully released and become part of the paste rather than sitting beside it. This is where the dish lives or dies: turmeric powder cannot replicate what fresh kamin releases only under sustained pounding. The colour should be vivid, almost luminous, and the smell sharp and earthy.
5
Add the charred, peeled shallots and pound until they are fully incorporated, so no pockets of watery shallot liquid remain pooled at the base of the mortar to thin the paste and weaken its structure. The mixture should be cohesive and hold together as a single mass.
6
Add the kapi and dried shrimp and pound until both are fully absorbed into the paste, so the fermented, salt-deep character of the kapi binds with the chilli and turmeric base rather than sitting as a separate layer — under-pounding here leaves the paste flat and divided. The finished paste should be dense, sticky, and aromatic, with the fermented shrimp note coming forward clearly; taste a small amount pressed on the back of a spoon to confirm the salt-fermented-earthy character is pronounced.
7
The finished paste should be smooth enough to disperse evenly into sour liquid — tamarind water or green mango — without visible lumps. Press a small quantity between the fingers; it should hold together and feel homogeneous, not granular. Store covered and refrigerated if not using immediately.
III
Quality Hierarchy
01
Reserve — Wild-harvested fresh kamin with visibly deep orange flesh; hand-made kapi from a single-source Southern Thai producer; long dried red chillies of known provenance, soaked and worked in a heavy granite mortar seasoned by long use.
02
Estate — Fresh turmeric from a specialist Asian grocer with firm, unshrivelled rhizomes; a reputable kapi brand with a clean, fermented — not putrid — aroma; good-quality dried red chillies with intact, pliable skin after soaking.
03
Market — Fresh turmeric from a general market produce section; standard supermarket kapi; any long dried red chilli available locally, ensuring it is soaked sufficiently to remove all brittleness.
04
House — Frozen fresh turmeric, thawed and patted dry — acceptable though some volatile oils will have diminished; commercially prepared kapi of any accessible brand. Turmeric powder is not an acceptable substitution at any rung.
IV
Sensory Tests
◇Sight. The paste is uniformly vivid yellow-orange with no visible chilli skins, shallot pieces, or turmeric threads remaining.
◇Smell. The aroma is sharp, earthy, and camphor-forward from the fresh turmeric, underpinned by a pronounced fermented shrimp note from the kapi — neither element should be muted.
◇Touch. A small amount pressed between the fingers holds together as a cohesive, sticky mass with no granular particles or pooling liquid.
◇Sight. Charred shallot skins blister and pull away cleanly from the flesh, confirming sufficient charring — the flesh inside should be softened and lightly caramelised.
◇Where it lives or dies. Fresh turmeric must be pounded until no fibrous thread or raw slice remains — no powder substitution and no abbreviation of the pounding will produce the volatile-oil content and camphor-earth dimension that defines gaeng som.
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