Remove the skin from tamarinds along with any big strings attached to the fruit. Cut each tamarind into several pieces with your hands
Rinse quickly on a colander with cold water to remove any dusty spots.
Place in a medium bowl and add 2 cups of hot water. Cover with a lid or a plate and let it rest for 10 minutes.
In another medium bowl, place a strainer and add the tamarinds with the cooked water. Mash it with a spatula or your clean hands to squeeze the juice/pulp out of the seeds and the hard fiber. Push down the pulp thru the strainer to extract all of the tamarind pulp.
Add a little more water at the time (no more than 1 cup water) to strain any remaining pulp. Scrape off any pulp attached to the outside/bottom of the strainer. Discard the tamarind fiber and seeds.
In a medium sauce pan, add the tamarind pulp from the bowl.
Bring to a soft boil and then lower heat to medium low. Cook for 5 minutes.
Remove from heat and let it cool down completely.
Store in glass jars with an airtight lid in refrigerator. Keeps for 1 month in fridge and up to 6 months in freezer.