QUESTION: I love espresso and the coffee crema on top of it, but what is coffee crema made of? — Tanya N.
ANSWER: When most shots of espresso are properly pulled, the crema on top of the cup is the result. We’ll tell you exactly how coffee crema is made and what it is made of.
Coffee grounds begin to store carbon dioxide inside of them when they are roasted. After the roasting process, the beans start to release the carbon dioxide. When espresso is made, hot water moves through those coffee grounds at high pressure, allowing the carbon dioxide to pick up delicious oils from the coffee beans. The crema happens when bubbles of carbon dioxide move through the coffee to the top of the cup, along with the coffee oils they picked up.
Carbon dioxide bubbles are fragile and begin to explode as soon as the espresso shot is pulled. The remaining oils that hitched a ride on the carbon dioxide bubbles from the coffee beans then get mixed into your coffee, where they help make up the signature taste of a delicious cup of espresso.
Many coffee drinkers love the taste of crema and value its presence in their cup, but there are some out there who don’t like crema. These coffee drinkers either skim the crema from the top of the cup or stir it into their coffee. So does crema improve the flavor of espresso or make it worse?
Minerals inside the crema add to the super-rich mouthfeel of espresso as well as causing the aftertaste to linger longer. An espresso drink with crema usually has a more well rounded and complex flavor than one without.
However, especially with light roast coffee, a quality espresso can come without crema, as not much carbon dioxide gets into the beans while they are roasted. Crema is a signal that the espresso beans used were high quality and that they were ground at the appropriate setting for how they were prepared.
This happens because lots of factors go into the flavor of a quality coffee beverage. If the grind size, brew time, level of roast on the coffee beans or their freshness is off, the whole drink is at risk—crema or not. What the crema tells you is that the barista who made the drink knows what they’re doing. It also tells you that the coffee your barista was working with is made with quality beans and has the appropriate grind setting.
So now you know that crema is made of the coffee oils and minerals picked up by carbon dioxide bubbles as they travel out of the grounds and into the hot water. Learning about what coffee crema is made of should help you understand why espresso with crema is so delicious.