Fermentation is the process of converting organic substances, which is often specifically initiated in biotechnology. In this process, substances are converted with the help of bacteria, fungi, cell cultures or by adding enzymes known as ferments. In the context of coffee production, fermentation plays an important role because it mainly causes the breakdown of tannins in the coffee beans. The fermentation process takes place during the wet processing of coffee beans, where the beans are soaked in water after the pulp has been removed. This gives the coffee a lively flavour and a pronounced acidity. It is important not to ferment the beans for too long to avoid contamination by detached pulp.
Fermentation plays a crucial role in coffee production as it facilitates the removal of the sticky residue that covers the parchment skin of the coffee beans. It also contributes to the formation of aromatic compounds and significantly influences the taste and quality of the coffee. Because of its impact on coffee flavour, the fermentation process is now often carefully controlled to ensure a slower and more consistent process.
Although fermentation and gärung are sometimes used interchangeably, there is a difference between them. Fermentation can take place under both aerobic and anaerobic conditions and refers to the transformation of organic substances, while gärung specifically refers to the anaerobic process without oxygen.