A complex spice mix, normaly heavy on the ginger, galangal and chilli, with the sour flavour coming from tamarind paste and rice vinegar. Many regional variants
Chinese hot and sour: various combinations of soy sauce, rice vinegar, chil-garlic paste, ginger, wok-scorched hot peppers, white pepper, sherry or rice wine, broth, cornstarch
Galanga(l) is typical of Thai style hot n sour which also relies on Nam Pla (fermented fish sauce),