The word espresso is derived from the Italian word for express since espresso is made for and served immediately to the customer.  A double espresso is a 47-62.5 ml (1.5-2 ounce) extract that is prepared from 14-17 grams of coffee through which purified water of 90℃-95℃ degree has been forced at 8-10 atmospheres of pressure for a brew time of 20-28 seconds.  The espresso should drip out of the porta-filter like warm honey, have a deep reddish-brown color, and a crema that makes up 10-20% of the beverage.  Espresso brewing is defined by four "M's": the Macinazione is the correct grinding of a coffee blend, Miscela is the coffee blend, Macchina is the espresso machine, and Mano is the skilled hand of the barista.  When each factor of the four M's is precisely controlled, the espresso beverage that is produced is the ultimate coffee experience.