What is crema on an espresso?
The crema is a thick, reddish-brown foam that floats on the surface of a freshly poured espresso. Composed mainly of oils, proteins, and sugars, the crema is one of the primary distinguishing features of a properly brewed espresso; thick and smooth, it is where the aroma of the espresso dwells. Since the crema will begin to disappear about sixty seconds after the espresso shot has been poured, be sure to serve or drink your espresso immediately!