Mix the tamarind with water in a bottle or other covered container and let it stand at room temperature for one to three days, then open very carefully because of carbon dioxide buildup.

Filter out the tamarind solids, mix the liquid with sugar to taste, and serve the juice. If the juice is too tart, add water. You can also refrigerate for a more refreshing taste. You can also use the juice to provide delicious tartness to your meals. Perfect sourness-bringer to your uji.