What is the Fermentation Nature of Coffee Processing Methods? What Types of Fermentation Exist in Coffee?

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FrontStreet Coffee Briefing on Coffee Fermentation

In coffee processing methods, fermentation occurs to varying degrees. Let's explore what the essence of coffee fermentation truly is.

The essence of fermentation is the action of microorganisms and enzymes on sugars, proteins, and chlorogenic acids in coffee, producing chemical components that affect flavor and mouthfeel. To determine what kind of impact fermentation has on coffee, we need to analyze the type and degree of fermentation.

Types of Fermentation

The first influencing factor is the type of microorganisms. Different microorganisms produce different changes during fermentation. Microorganisms can come from natural bacteria in coffee-producing regions, or from artificially added bacterial cultures. Adding specific bacterial cultures can guide the development of particular flavors. At the same time, aerobic and anaerobic environments technically belong to environmental control, but in reality, they select the types of microorganisms participating in fermentation by controlling oxygen content, so the fundamental difference still lies in the microorganisms.

Acetic Fermentation (Aerobic Fermentation): Cleaner, bright and lively acidity, citric acid and citrus acid;

Lactic Fermentation (Anaerobic Fermentation): Round, high body thickness, relatively low cleanliness, malic acid and tartaric acid;

Mixed Fermentation: Full, medium body thickness, smooth, fruit acids, amino acids, nuts, and cream.

What Affects the Degree of Fermentation?

The degree of fermentation depends on the speed and time of fermentation. The speed of fermentation mainly considers whether the environment is suitable for the survival and activity of microorganisms. Are there sufficient reaction materials (sugars, proteins, etc.)? Are there appropriate reaction conditions (temperature, pH, humidity, etc.)?

Yeast Treatment

Adding yeast during the green bean processing process to form specific flavors.