What to Do When Espresso Lacks Crema, and What Is Espresso Crema Made Of?

What is Espresso Coffee?

Espresso is a very small cup of coffee that can be finished in just two or three sips. Its flavor is extremely strong, which many people find difficult to accept. The small serving size and intense flavor are reasons why espresso has limited appeal in China. However, when mixed with milk to create lattes or with water to make Americanos, these drinks become very popular.

The appearance of espresso in a cup features dark coffee liquid at the bottom with a layer of golden-brown crema floating on top. Is crema made of oil?

We all know that peanut oil is extracted from peanuts, and dark-roasted coffee beans secrete oil on their surface. So what constitutes that layer of crema extracted by the espresso machine?

Italians call this top layer "Crema," and this unique, rich crema can only be produced by espresso machines, with pressure being the key factor. An espresso machine generates 9 bars of water pressure to "squeeze" the coffee puck. The carbon dioxide in the coffee grounds, due to excessive pressure, creates a supersaturated state in water, preventing CO2 from releasing and instead directly dissolving into the coffee liquid. During the extraction process, fats in the coffee are emulsified, and these fats encapsulate the carbon dioxide. Since they are lighter than water, they gradually separate, with the golden crema floating to the surface, creating a beautiful appearance.

So this golden, delicate coffee crema is formed by insoluble coffee oils encapsulating carbon dioxide. How can one ensure that espresso has beautiful crema?

What Constitutes Quality Crema?

According to FrontStreet Coffee, quality crema appears golden-yellow, with a delicate surface and uniform color. When swirled, it should feel smooth like cream, with noticeable adherence to the cup walls. Not only does it enhance the visual appeal of espresso, but it also enriches the taste and aroma when consumed, protects the coffee's flavor, and facilitates latte art fusion and pattern stability when making hot milk-based coffee. Perhaps these are the reasons why people go to great lengths to pursue the perfect Espresso!

How to Achieve Rich Crema

Based on extraction experience, FrontStreet Coffee believes that obtaining rich crema is actually quite simple. First, when purchasing coffee beans, select beans with high oil content and sufficient carbon dioxide, such as medium-dark roasted beans within their optimal tasting period (45-60 days), or fresh espresso blend beans containing a certain proportion of Robusta. For example, on FrontStreet Coffee's bean menu, both the "Frontsteet Commercial Blend" and "Frontsteet Classic Blend" espresso coffees easily produce beautiful crema precisely because they contain a small amount of Robusta beans.

When the right coffee beans are selected, they must be paired with fresh grinding, stable high temperature, sufficient extraction pressure, and reasonable extraction parameters. Satisfying these key factors is essential to obtaining espresso rich with dense crema.

Analyzing Crema Quality

Overall, the fresher the beans and the darker the roast, combined with higher equipment pressure and more stable performance, the better the coffee crema's expressive qualities. Next, FrontStreet Coffee will teach you how to judge the quality of Espresso by observing crema patterns, thereby solving common extraction problems.

No Crema or Thin Crema:

The problem likely lies in aged beans (including improper storage and pre-ground coffee). The longer beans are stored, the more gas exchange occurs with air, resulting in greater carbon dioxide loss and consequently less crema. Additionally, insufficient espresso machine pressure, low temperature, overly coarse grind, or inadequate tamping pressure are also causes of insufficient crema.

Whitish Crema:

If your extracted espresso has decent crema thickness but lacks golden coloration and tastes predominantly sharp and acidic, it's likely because you used beans with a lighter roast. For example, using pour-over beans that emphasize fruity acidity for espresso can easily result in unpleasant acidity and astringency due to under-extraction, accompanied by lighter-colored crema.

Coarse, Bubbly Crema:

This type of espresso crema typically has a very short duration and dissipates quickly. This is caused by beans that are too fresh. Freshly roasted beans contain large amounts of carbon dioxide. When excessive gas is forced into the coffee liquid, the emulsified oils cannot encapsulate the gas and easily break down.

Clotted Crema:

This type of espresso typically shows obvious "lumps" when swirled, with uneven crema surface and poor fluidity, similar to over-foamed milk that's difficult to spread and blend.

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473