You'll get the best crema using good quality coffee that's about 1-2 weeks from the day it was roasted so always check the roast date. The tiny hole in every coffee bag is not there to sniff the coffee beans, but to allow the coffee to degas the CO2 that's in freshly roasted coffee.
Make espresso in a small clear glass cup when you want to look at crema. You can see the crema very clearly and watch as it fades away over time.
Latte art can't be made without crema. The contrast between the crema and steamed milk is what creates the design.
Most coffee shops will serve an espresso shot with a spoon so that the crema can be stirred into the rest of the drink. You don't need to stir if you don't want to and the spoon is only there as an option.
The crema can tell you a lot about an espresso, whether it’s been pulled too long (the crema has white flecks) or too short (it’s dark and thick).
How to Get Good Crema
Use fresh coffee, but not too fresh. Coffee that is about 1-2 weeks from the roast date is ideal to get good crema. This gives the coffee enough time to release gasses (including CO2) produced by the roasting process. Most bags will tell you when the coffee was roasted and if it's not labeled with a date, it's most likely old coffee. Coffee that's too fresh and roasted just a couple of days ago will have too much CO2 and will result in too much crema, leaving the espresso unbalanced.Freshly grind coffee. Crema is a sign of freshness, and coffee begins to go stale once it's ground.Use a good espresso machine using enough pressure. Cheaper espresso machines in the ($100-$400 range) don't get the water hot enough or create enough pressure to pull a good shot of espresso with bad crema.