What is the foam on coffee and is crema really oil?

The golden foam on an espresso, called crema, is not oil in the true sense. It forms when pressurized extraction from a coffee machine forces carbon dioxide into lipid substances seeping from the coffee, creating countless tiny bubbles. Those bubbles build the dense surface layer that people often mistake for oil.

The name comes from Spanish, where crema means cream, chosen because the layer resembled cream whether still or shaken. Since pressurized coffee machines became common, that visual similarity has fed the idea that crema signals quality. In practice it is a foam structure, not an oily film, and judging a shot by it alone can mislead.

Many people, upon first seeing the golden, dense foam on the surface of an espresso, instinctively assume it is the coffee's oil, and even use it as a standard for judging the quality of an espresso. But did you know? This layer, called Crema, is not actually oil in the true sense, but a "visual illusion" made up of countless tiny bubbles. Today, Front Street Coffee will play the role of a Sherlock Holmes in the coffee world, taking you step by step to uncover the various misunderstandings about Crema, to see who it has really "deceived," and why it causes so many people to misjudge. If you are also curious about this golden foam on espresso, why not follow along and read on.

"What happened to the oil! Who did it deceive!! Does the scam mean that because the oil looks so delicious, it lures many people into drinking espresso?" This is the question many people have after seeing the entry (I made that up!). So what is the truth of the matter? Great! Today, Sherlock Holmes of Front Street Coffee will reveal just who the oil, as the "protagonist," has deceived!

Oil "Scam" One: It Is Not Oil

Although this golden substance has been called oil for a very long time, in reality, this substance does not count as oil!

With the birth of the pressurized coffee machine, coffee, like a game character, gained a brand-new "skin" enhancement. Under the pressurized extraction of the coffee machine, carbon dioxide is infused into the lipid substances seeping out of the coffee, forming countless tiny bubbles, and after these bubbles seep out, they become a thick, dense exterior. This is what we now call crema. But in fact, this is merely an image created collectively by countless bubbles, and not oil in the true sense.

Because this layer of bubbles resembles cream whether left still or shaken, people at the time gave it the name "Crema." In Spanish, Crema means cream, so the meaning of this name at the time was: coffee cream.

The above content is compiled by CoffeeHunters, a coffee news website.