Espresso is a concentrated coffee blend that is brewed hot and fast under pressure, resulting in a potent swallow of coffee that is luxuriously creamy, with a kiss of foamy crema and a lingering aftertaste. It is similar to coffee in taste, but highly concentrated, so its almost as if you are having a small mug of coffee in just a few sips. To fully understand what makes a perfect espresso shot, its important to understand the four key qualities that contribute to its flavor profile: bitterness, sourness (or acidity), sweetness, and the aftertaste. All coffees taste bitter, but for espresso, the perceived bitterness can be especially powerful. The acidity of espresso can shine a spotlight on that characteristic, for better or worse. The sweetness of espresso is important to achieve the right balance of taste elements. The aftertaste of espresso should be pleasant and flavorful. The aroma of espresso is a combination of earthy, nutty, chocolatey, and caramel-like scents that intermingle and create a rich and intense smell. Some even say they detect floral or fruity notes in their espresso, depending on the origin of the beans used. The taste of espresso changes as you sip, and the flavors should dance and change as the espresso moves from the front of the tongue, to the back, and finally down the throat.