To ensure the freshness of the coconut, shake it and listen for the gurgle of liquid inside.
To open a coconut, pierce the three dark dots that form a triangle on one end of the shell.
Pour out the liquid.
(Discard liquid or use in other ways.) Using a hammer, or the dull side of a cleaver, tap the shell all over until it cracks and breaks.
Pry out the meat of the coconut.
Grate the white coconut meat or, using a strong, sharp knife, chop the meat finely, leaving the brown skin on the meat.
Place the coconut and water in a blender or food processor and blend 1 or 2 minutes to achieve a crudely pureed mixture.
Line a strainer with a double thickness of cheesecloth and place it over a bowl.
Pour coconut mixture into the strainer, allowing the hot liquid to drain through.
When it is cool enough to handle, pick up the cheesecloth, twist, and squeeze out as much remaining liquid as possible.
Discard the cheesecloth and depleted coconut.
Use coconut milk immediately, or refrigerate briefly.
Freeze any coconut milk that you do not plan to use in 1 or 2 days.