Kaeng som’s characteristic sour taste commonly comes from tamarind.
Kaeng som, also called gaeng som, is a sour and spicy Southeast Asian curry or soup traditionally made with fish and vegetables. Tamarind, known in Thai as makham, supplies the dish’s signature tartness. Palm sugar is often added as a sweetener, but it balances the sour flavor rather than creating it. Coconut milk is generally absent from kaeng som, which helps distinguish it from richer, creamy curries.
The name covers related dishes across Thailand, Laos, and Malaysia. Central Thai versions may use tamarind prominently, while southern Thai preparations can combine tamarind paste with assam fruit or lime juice. Southern versions are also associated with turmeric and a particularly hot, salty, sour profile. Local recipes can therefore vary even when they share the same general identity.
Shrimp and fish are both common, and vegetables may include cabbage, daikon, long beans, or water spinach. A popular Thai combination pairs the curry with shrimp and a cha-om omelet. Because “sour curry” describes a family of regional preparations, other acidic ingredients may appear, but tamarind remains the standard answer for the dish’s commonly cited souring agent.