The juice of the pulp around the seeds of the tamarind, sometimes called the Indian date, is used to give a fruity, sour flavor to many Asian curries and spicy dishes. Those that do not contain coconut milk tend to be cooked in tamarind juice. Generally, tamarind is used with seafood while coconut accompanies meat and poultry dishes.
Tamarind is available in several forms, the most common being brown or black blocks of concentrated pulp, which must be soaked in hot water before using. When the liquid has reached the desired acidity, like very strong lime juice, it is strained and used for cooking. In Thailand, a sweeter variety of tamarind is eaten fresh as a snack.
Some Asian food shops sell bottled tamarind concentrate in a thick liquid form that needs no further straining. The concentrate is very tart and should be diluted in the proportion of one part tamarind concentrate to two parts water. If you cannot find any tamarind, you can substitute fresh lime juice instead.
** Thai Recipes