Black gold tea is a kind of black tea, and the highest quality black tea is called black gold black tea. Black tea is named for its black appearance. Black tea belongs to one of the six major teas and belongs to post-fermented tea. The main producing areas are Guangxi, Sichuan, Yunnan, Hubei, Hunan, Shaanxi, Anhui and other places.

The tea-making technology of black tea generally includes four processes: enzyme fixation, rolling, fermentation and drying. According to geographical distribution, black tea is mainly divided into Hunan black tea (Fu tea, Liang Qian tea, black brick tea, Sanjian tea, etc. ), Hubei Blue Brick Tea, Sichuan Tibetan Tea (Border Tea), Anhui Ancient Black Tea (ancha), yunnan black tea (Pu 'er Cooked Tea), Guangxi Liubao Tea and Shaanxi Black Tea (Fuzha Tea).

There are more than 500 kinds of active ingredients in tea. We can first look at the different performances of its main quality components in taste.

1, L- theanine: 1-2% of the dry weight of tea and 70% of the total free amino acids. It is the characteristic amino acid of tea and the main ingredient that makes people moist and sweet. Theanine is an amide compound with caramel fragrance and fresh taste. Studies have proved that its content is closely related to the quality of tea.

2. Caffeine: an important flavor-presenting substance with bitter taste, which has a fresh and refreshing taste when combined with catechins and theaflavins;

3. Tea polyphenols: the general term for polyphenols in tea. It is a complex compound including catechins and flavonoids, in which catechins account for 60-80%, which is one of the main components that form the color, aroma and taste of tea. Tea polyphenols are unstable and prone to chemical reactions such as isomerization, hydrolysis and oxidative polymerization, and their content changes in different degrees during processing. If the content is small, it tastes light, light, non-irritating, neither bitter nor sweet; If the content is high, it is strong, stimulating and bitter with sweetness;