Espresso is a full-flavored, concentrated form of coffee that is served in “shots.” it is made by forcing pressurized, hot water through very finely ground coffee beans. This process is called “pulling a shot. Unlike most coffees, espressos have “crema.” this is a froth of reddish-brown color that forms when air bubbles combine with the soluble oils of a fine-ground coffee. The crema adds to the rich flavor and alluring aroma of espresso.