When you eat tamarind, it is normally very sour – which is great because it is used to add sourness and flavor to many cuisines.
However, sweet Tamarind is difference species which is sweet. This only happens when the fruit is allowed to ripen on the tree before harvesting.
This changes the flavor significantly..and is not a treated variety of Tamar ind but rather another species. It is grown in Thailand, in a specific region called Petchabun.