A clear, bright, sweet-sour soup of fish, tomatoes, pineapple, and tamarind in a light broth, garnished with bean sprouts and fresh herbs. Canh chua (literally 'sour soup') is the Vietnamese parallel of Thai gaeng som (Entry TH-29) — a clear, broth-based soup acidified with tamarind, with fish as the protein, and a sweet-sour balance as the defining flavour principle. Its Vietnamese character: the large quantity of fresh herbs and pineapple added at service; the lightness of the broth; the absence of a curry paste.
**The tamarind:** Tamarind water (Entry TH-18 principle) — prepared and calibrated before adding to the soup. Vietnamese canh chua uses more tamarind than Thai gaeng som typically does — the sourness is assertive and intended to be the dominant register from the first spoonful. **The pineapple:** Fresh pineapple pieces added in the last 5 minutes — the pineapple provides both sweetness and additional acid, and its enzymes (bromelain) continue to soften the fish pieces if left in the hot broth too long. Add close to service. **The fish:** Firm white fish (catfish, snapper, or sea bass in chunks). Alternatively: elephant ear fish (cá tai tượng) when available — a specific Vietnamese freshwater fish served split and deep-fried in some canh chua versions. **The garnish:** Rice paddy herb (ngổ ôm) — a herb specific to Vietnamese cooking with a slightly cumin-citrus note, added at service. Bean sprouts. Fresh chilli. The garnish is served in quantity alongside the soup, added by the diner.
Naomi Duguid & Jeffrey Alford, *Hot Sour Salty Sweet: A Culinary Journey Through Southeast Asia* (2000); Naomi Duguid, *Burma: Rivers of Flavor* (2012)