The first important rules about espresso:\r\n\r\nPreparing espresso is a genuine ritual fusing art and science, and it has its rules. \r\n\r\nThe Blend: Only a blend made up exclusively of Arabica coffees provides a harmonious, well-balanced taste striking happy compromise between bitterness and acidity as well as imparting rich,fragrant aroma and a full body. \r\n\r\nThe Grinder: You can experiment with an adjustable grinder until you find the perfect setting (allow an extraction time of between 15 and 20 seconds for home brewing). The exact dose of coffee: 6 to 7 grams per cup! \r\n\r\nThe Machine: Espresso machines must be able to heat water up to 90’C (194’F) and to exert pressure equal to 9 atmospheres or more. \r\n\r\nThe Operator: His or her main function is to follow the other three rules and to press down the coffee in the machine with just the right touch of the hand.