In the world of espresso, you often hear mention of crema. What is crema, and why is it so important?
Crema is actually the frothy layer of espresso that forms at the top of the cup. For avid espresso drinkers, it is the Holy Grail of coffee consumption. When baristas start a shot of espresso, the first few seconds of the pour become the lighter, foamy crema. This layer rises to the top as the denser, darker espresso fills the remainder of the cup.
Crema is only relevant in coffee drinks that do not contain milk. There are many different types of espresso drinks, but beverages with milk will always occupy the top layer of the glass because foamed milk is lighter than the espresso underneath. Crema is relegated to espresso only.
There are quite a few factors that go into crema creation. First, the fat/oil content of the bean is emulsified during the brewing process when hot water is forced through tightly packed and finely ground beans. The more the bean maintains sugar and fat content during processing, the better the crema.
Second, crema depends on roasting, specifically the timing of it. After coffee is first roasted, carbon dioxide is out-gased in the beans. If those beans are ground and used within the first few days, any crema could be the result of too much carbon dioxide and lead to a sour flavor in the coffee. Wait too long, and there may not be enough. The ideal time to serve espresso is around four days after the beans were roasted. Other factors such as the grind, tamping, brewing pressure and brewing temperature all affect the integrity of the crema.
Finally, there are the machines that deliver the espresso. By forcing water through tightly packed and finely ground beans, the coffee is aerated during extraction, creating the fine espresso foam that everyone desires.
Crema and the concepts of flavor and aroma.
A few reasons crema is valued are flavors and aromas. These can be accentuated with crema. And now, there are new definitions by which we can categorize coffee flavors and aromas. Discover them in the latest coffee flavor wheel.