Cambodia's sour soup tradition — samlor machu (samlor = soup, machu = sour) — is the direct Cambodian counterpart of Vietnamese canh chua (Entry ND-17) and Thai gaeng som (Entry TH-29). A clear or lightly thickened broth acidified with tamarind, sour tomatoes, or pineapple, with fish or pork, and herbs. The Cambodian version has its own specific character: prahok (Entry ND-29) as the primary umami seasoning, a slightly sweeter balance than the Vietnamese version, and the characteristic Cambodian kaffir lime leaf-galangal aromatic base.
**The souring agents:** - Tamarind water (primary): Entry TH-18 preparation. - Sour fruit: green mango, starfruit (carambola), or unripe pineapple — these add sourness and a specific fruity aromatic alongside the tamarind. - Tomato: provides body and a mild acid. **The prahok seasoning:** 1 teaspoon of prahok (dissolved in water, strained) added to the broth early in the simmering — providing the fermented depth that distinguishes Cambodian samlor machu from the Vietnamese and Thai equivalents. **The herbs:** The Cambodian herb profile: lemongrass, galangal, kaffir lime leaf, saw-tooth coriander, and sometimes fresh rice paddy herb (ngổ ôm — used in Vietnamese cooking as well, Entry ND-17 note).
Naomi Duguid & Jeffrey Alford, *Hot Sour Salty Sweet* (2000); Naomi Duguid, *Burma: Rivers of Flavor* (2012)