What is the fermentation of coffee beans? What is fermentation?

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What is fermentation?

To put it simply, fermentation is the process by which sugar and starch are decomposed into acid or alcohol. Let's explore more deeply that yeast and bacteria are very important for fermentation.

Yeast fermentation, called Saccharomyces cerevisiae, is a natural wild yeast that is also found in grapes, cocoa beans and other fruits. It is currently used in wine making, cocoa bean processing and coffee processing. "

And the strain is lactic acid bacteria.

Different biological changes take place in the natural fermentation of coffee. Yeast produces enzymes and lactic acid bacteria decompose the sugar in coffee pectin. Lipids, proteins and acids in sugars are degraded and converted into alkyd (alcohol acidic acids). The smell, color and pH of coffee will change, and so will the pectin composition of coffee.

The fresh coffee fruit is wrapped in an exocarp (also known as a pericarp), which turns red or yellow when the fruit is ripe. The mesocarp consists of pulp and mucus, and the endosperm consists of two beans (germs) containing embryos. Each bean is wrapped in a silver coat (seed coat or endosperm) and coated with parchment (endocarp).

The purpose of coffee fermentation is to remove the mucus attached to the parchment after the pulp of the coffee is removed. In the treatment process, the primary microorganisms of coffee are in full contact with the surface of coffee. A variety of microorganisms such as bacteria, molds and yeast interact to break down carbohydrates and polysaccharides into alcohols.

There are two common methods of coffee treatment: dry treatment, usually called sun exposure, and wet treatment, usually called washing.

In the process of coffee fruit to raw coffee bean treatment, there will be more or less "fermentation", whether it is washing treatment, honey treatment, or sun treatment will undergo this chemical change process. Different substances involved in fermentation (coffee peel, coffee pulp, coffee pectin, species of bacteria, distribution of bacteria), different fermentation environment (water and water, oxygen and oxygen, PH environment, etc.), different drying process (container material, natural sun, drying equipment, turning times, etc.), resulting in different post-treatment flavor and taste.

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