A Brief Analysis of Coffee Crema: What It Is, Its Effects on the Body, and Reasons for Inadequate Extraction

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Espresso is a small, exquisite coffee with rich golden crema. It can be said that this layer of golden crema is a major hallmark of espresso, which Italians call "Crema."

What is Coffee Crema?

Coffee crema is mainly composed of carbon dioxide and insoluble oils from coffee grounds. As we all know, coffee beans contain gases like carbon dioxide after roasting. When modern semi-automatic espresso machines extract coffee, they generate 9 bar of pressure to "squeeze" the coffee puck. Due to the high pressure, water becomes supersaturated with carbon dioxide, so the carbon dioxide cannot escape and directly dissolves into the coffee liquid.

During this process, fats in the coffee are emulsified. These fats encapsulate the carbon dioxide. Since they are lighter than water, they gradually separate, and the golden crema emerges on the surface, creating a beautiful appearance.

What Factors Affect the Richness of Espresso Crema?

1. Coffee Beans

We know that espresso crema is composed of carbon dioxide and insoluble oils, which is related to the roast degree and bean variety. The darker the roast, the richer the content of oils and carbon dioxide. Coffee beans like Robusta contain more oils, so the extracted espresso will have richer crema.

FrontStreet Coffee's Sunflower Warm Blend coffee beans and FrontStreet Coffee's Commercial Blend coffee beans can both provide rich coffee crema.

FrontStreet Coffee Sunflower Warm Blend Coffee Beans

This is FrontStreet Coffee's flavor-oriented blend coffee bean, composed of 70% FrontStreet Coffee Honduras Sherry Coffee and 30% FrontStreet Coffee Ethiopia Yirgacheffe Natural Red Cherry. FrontStreet Coffee Honduras Sherry Coffee provides rich coffee crema, and this FrontStreet Coffee blend brings flavors of sherry, vanilla, cream, chocolate, and caramel.

FrontStreet Coffee Commercial Blend Coffee Beans

Uses Brazil, Colombia, and 10% Robusta. The taste is classic, and this blend brings rich crema and texture, with caramel sweetness, nuts and cocoa, dark chocolate flavors, balanced sweet and sour, slightly bitter, with a persistent aftertaste. Coffee beans from the Huilan region of Colombia have pleasant acidity, fragrant aroma, moderate acidity, and rich sweetness that is intriguing. Coffee beans from the Cerrado region of Brazil have comfortable bitterness and are extremely smooth to drink. Robusta provides rich crema. This FrontStreet Coffee Commercial Blend is suitable for coffee shops and beverage shops of various sizes.

2. Extraction Pressure

Generally, the extraction pressure of semi-automatic espresso machines is around 9 bar, which is determined by the machine's performance. Some coffee machines now feature variable pressure extraction. Low pressure results in low extraction efficiency, while high pressure results in high extraction efficiency. The higher the pressure, the easier it is to extract coffee crema.

3. Flow Rate/Channel Effect

The flow rate is the speed at which coffee liquid flows down. Our extraction parameters ultimately aim for a flow rate result. For normal espresso, the first drop of coffee liquid should begin around the fifth second after pressing the extraction button, with a relatively uniform subsequent flow rate. The speed of the flow rate directly reflects whether the grind size and ratio are appropriate. If the first drop appears after more than 10 seconds (excluding pre-infusion), the coffee grounds might be too fine or the puck might be tamped too tightly. If the flow rate is too fast or there's spraying, the grounds are too coarse or channeling has occurred.

What Are the Reasons for No Crema When Extracting Espresso?

FrontStreet Coffee has summarized some customer feedback and identified several common situations:

1. Coffee grind is too coarse

Too coarse coffee grounds cause water to flow too quickly, resulting in incomplete extraction and thin, watery crema.

2. Insufficient pressure

Extracting rich crema requires 9 bar of pressure. If you notice your coffee is thin, you can check whether it reaches 9 bar of pressure.

3. Coffee beans are not fresh

Coffee crema is mainly composed of carbon dioxide and insoluble oils from coffee grounds. Carbon dioxide escapes over time. If the coffee is not fresh, the carbon dioxide content is low, so coffee crema cannot be produced.

4. Unreasonable extraction parameters

FrontStreet Coffee's espresso extraction parameters use a coffee-to-liquid ratio of 1:2, with extraction time between 25-28 seconds. This is for everyone's reference.

For more specialty coffee beans, please add FrontStreet Coffee's private WeChat account: kaixinguoguo0925

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473