Crema

The crema is the think layer of foam that sits on top of an espresso after it is extracted from an espresso machine.

The appearance of the crema can be use as an indicator of the quality of the espresso.

For example, coffee beans that are fresh are observed to produce more crema compared to those that are not as fresh. And the darker the crema, implies the darker the roast.

However, how quality is judged is also a subjective matter.

Some people might not desire the taste of coffee that is too fresh.

While baristas are sometimes fixated about the beauty that the perfect crema possess, do note that it is basically a by-product of brewing coffee using intense hot water pressure.