What exactly is an espresso? September 20 2014
A question that we've been getting a lot lately is, "what is an espresso?" To answer this, let's start with what an espresso isn't. An espresso isn't. An espresso isn't a specific bean, bean blend, or roast level. Any bean or roast level can be an espresso.
Espresso is coffee brewed by forcing water that's almost boiling through finely ground coffee beans under pressure. This pressurized brewing process results in very concentrated flavors. Espresso also forms the base of many of our favorite drinks - cappuccino, cafe latte, cafe macchiato and the Americano.
This chart from IcingOfTheCake summarizes it nicely: