Step 1Gently simmer the tamarind pulp in 4 cups water for 10 minutes. Remove from the heat, cover and let sit for 30 minutes.
Step 2Press the softened pulp through a sieve, breaking up the pulp and, if necessary, pouring some already-strained liquid through a second or third time to loosen the pulp enough to extract all the liquid. Discard the solids. You should have about 3 cups. Refrigerate tamarind liquid for up to a week or measure it into ice-cube trays and freeze for convenient future use.