I highly recommend this website for all types of information on coffee production in Puerto Rico. Felicidades Professor Miguel F. Monroig Inglés on a great website!!
The website is in Spanish, however, your browser should allow you to translate the text into whatever language you like.
PRAGWATER 
How to make Puerto Rican coffee
Ingredients:
1 / 2 cup water
2 tablespoons coffee
2 ounces boiled milk
1 tablespoon sugar (or to taste)
procedure:
1. Mix the coffee with water and boil 2 minutes.
2. Strain the coffee in coffee sock.
3. In a cup, combine brewed coffee with milk.
4. Add sugar to taste.
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