06/05/2022
🌱🌱In terms of tea, we may mention fully fermented, semi-fermented, and lightly fermented. But are they the same as the fermentation of other food (e.g. yogurt, vine, vinegar)?🧐
Let’s learn more about that!
🔍What is the fermentation?
The so-called fermentation usually refers to a certain decomposition process of organic elements.
Such phenomenon has been known for a long time, but nearly 200 years it has been understood its nature.🙂
🔍Tea fermentation
For tea, the same green leaf is processed into green tea, black tea, oolong tea, etc. by controlling biological oxidation, which is more like enzymatic reactions, perhaps better known as biological oxidation.
The bio-oxidation of tea is a series of oxidation processes of catechins that are promoted by oxidase after the cell wall is damaged.
In the cells of tea, catechins are present in the cell fluid, while the oxidases are mainly found in the cell wall, not in microorganisms.😮
So the cell wall needs to be broken. This also naturally explains why fermented tea needs to be kneaded. In black tea, the degree of oxidation of polyphenols is very high, which is called full fermentation; the degree of oxidation of polyphenols in oolong tea is about half, which is called semi-fermentation.
For example, in black tea processing, the purpose of fermentation is to oxidize the catechins contained in the leaves. The leaf color changes from green to copper red, resulting in the unique color of black tea.
After the cell membrane of the tea liquid is damaged, the polyphenols, amino acids and other substances in the vacuole are gradually oxidized. At the same time, due to the oxidation of catechins, some substances in the leaves undergo chemical action, resulting in the unique aroma and taste of black tea.
However, in the production of some other kinds of tea, there are also microorganisms involved in (especially Pu’er tea).
It is necessary to distinguish between fermentation in which microorganisms are involved and fermentation in the sense of biooxidation. Otherwise, the conceptual ambiguity will easily lead to misunderstanding of the formation mechanism of tea.😉😉
