Why is the crema important on the espresso?!
Answers: Espresso is traditionally taken black, the crema is on the top of the coffee, if you use top quality coffee you should get a thick creamy layer, the crema is important as it denotes the quality of the coffee. Also if the coffee starts to cool down the crema will disappear.
Espresso has cream?
The crema contains the most potent flavours, apparently.
It also makes the coffee look much better.
The crema on the top is caused by emulsion (cramming water into the oils in the coffee beans) and thus extracts the best flavors from the coffee.
Espresso machines use a great deal of pressure to accomplish emulsion and if crema isn't present then something is wrong.