What's the brown foam on top of an espresso?

The light brown foam that floats on top of an espresso is known, in Italian, as the “crema.” Distinguished by its caramel color, the “crema” is the essence of authentic espresso. The crema carries a variety of flavors that comprise the coffee bean. The presence of “crema” means the espresso is fresh and perfectly prepared. It is a natural froth produced by the pump pressure.