Fermented tea refers to tea made by chemical changes of tea leaves under the action of fungi or microorganisms. Common fermented teas are Pu 'er tea, black tea, oolong tea, black tea, etc. Each tea has different characteristics. Here is a brief introduction:

1. Pu 'er tea: Pu 'er tea is a kind of tea unique to Yunnan, which is formed by microbial (fungal) fermentation. Pu 'er tea has a unique taste of aging and heavy feeling, and it has the effects of reducing fat and weight, lowering blood fat and blood pressure, lowering blood sugar, resisting oxidation and relieving fatigue.

2. Black tea: Black tea, also known as "Tuocha", is a unique tea in Hunan, Sichuan and Yunnan. The production of black tea is to use microorganisms to ferment in the whole process under specific conditions such as temperature, humidity and time. Black tea tastes mellow, and the tea soup is red and thick, which has the effects of benefiting qi, promoting digestion and appetizing.

3. Oolong tea: Oolong tea is one of the traditional tea varieties in Taiwan Province, Fujian and other places. Its tea leaves are partially fermented, which is between green tea and black tea, so its taste is also different. Oolong tea is yellow or amber in color, refreshing in taste and rich in aroma, and has some health-care effects, such as losing weight, lowering blood fat, moistening lung and lowering blood pressure.

4. Black tea: Black tea is a fully fermented tea, mainly produced in China, Fujian, Yunnan and Anhui. Black tea is bright and red, sweet and lasting, and has the effects of refreshing the brain, promoting digestion and relieving boredom.

Generally speaking, fermented tea has a unique flavor and aroma because of its unique fermentation technology, and has many health-care effects, which is suitable for tea lovers to drink.