Why Pour-Over Coffee Lacks Crema: What Is Coffee Crema and Why Do Coffee Beans Produce Oil?

"Why doesn't pour-over coffee have crema? Is it because the beans aren't fresh?" FrontStreet Coffee recently came across this discussion topic. Pour-over coffee isn't completely without crema—while it may not be visible, it manifests in the mouthfeel.

What is coffee crema?

When it comes to coffee crema, what might first come to mind is the golden crema layer on espresso. However, you won't see this golden crema in drip coffee or immersion coffee. Why is this? This is when we need to understand pressure extraction.

During the roasting process, coffee beans generate a large amount of carbon dioxide inside them. This carbon dioxide is rapidly released after the beans are ground. Espresso extraction requires high pressure to quickly extract the coffee's flavor. Under 9 bar pressure and in a sealed environment, carbon dioxide and water reach a supersaturated state. At the same time, the coffee oils are emulsified and then encapsulate the carbon dioxide, extracting together with the coffee liquid. Since oils are lighter than water, the extracted coffee gradually separates into layers, so the golden crema floats to the surface, looking quite enticing.

Factors affecting coffee crema

The amount of coffee crema primarily depends on the coffee bean variety. Among them, Robusta varieties have higher oil content than Arabica varieties. This is also why after FrontStreet Coffee adds a small amount of Robusta coffee beans to their espresso blend, the crema immediately becomes richer.

Secondly, it's related to the degree of roasting. As the roasting depth increases, more carbon dioxide is produced. When coffee beans reach a dark roast, they experience high dehydration resulting in oil emergence. This also explains why when making SOE (Single Origin Espresso) coffee, no matter how lightly roasted coffee beans are extracted, the crema will appear thin.

Why can't you see coffee crema in pour-over coffee?

Because of the coffee filter paper. Coffee filter paper is made by stacking pulp fibers. The thicker the filter paper feels, the slower the filtration speed, and the better the effect of filtering coffee powder and coffee oils. However, is thicker filter paper always better? Overly thick filter paper can slow down filtration speed, prolonging contact time between coffee grounds and water, which can easily lead to over-extraction.

Coffee filter paper of moderate thickness can effectively filter fine coffee particles while also blocking over 80% of coffee oils. The oils that successfully "pass through" form an extremely thin oil layer that is difficult to observe with the naked eye. However, the presence of oils can be felt through oral sensation. The creamy and smooth sensations often mentioned by FrontStreet Coffee are manifestations of coffee oils in the mouth.

How can you brew pour-over coffee with crema?

To preserve the crema in pour-over coffee, you need to remove the filter paper. ("How do you separate coffee grounds without filter paper!") FrontStreet Coffee has heard everyone's concerns. Besides coffee filter paper, there are also pour-over coffee metal filters and pour-over coffee filter cloths for filtering coffee grounds.

Due to their structure, metal filters can retain most of the oils in filtered coffee, but the disadvantage is that fine coffee particles easily pass through the filter holes, resulting in less than ideal coffee mouthfeel. While filter cloths can effectively block fine particles and retain some oils, cleaning them is quite painful... because there are oils, so after each use, they must be thoroughly cleaned multiple times to ensure all residual oils are removed, otherwise they will affect the coffee flavor during the next brewing.

Important Notice :

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FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473