The method of making tea is one of the bases for the classification of "six major teas". Under different production methods, tea will show different qualities, first of all, color. Like green tea, it has the characteristics of "clear soup and green leaves"; Black tea has the characteristics of "red soup and red leaves".

The "clear soup green leaves" of green tea come from the process of enzyme fixation. The enzyme activity of newly picked tea leaves was destroyed after high temperature inactivation, which prevented the tea leaves from turning red, thus retaining the green color. The green smell of fresh leaves is removed and the fragrance of green tea is produced.

The "red soup and red leaves" of black tea come from the fermentation process. The essence of fermentation is to destroy fresh leaf tissue and make the original disjoint contents contact each other and oxidize.

Therefore, the kneading of tea is the key. When rolling, the cells of fresh leaves are forcibly destroyed, the tea juice comes into contact with air, and the fermentation of tea begins. Generally speaking, black tea has a longer kneading time and greater pressure than green tea, and then it will not be "killed" after a separate "fermentation" process. This has formed the unique characteristics of black tea.

Green tea and black tea have different compositions.

When drinking, you can find obvious quality differences between the two.

Green tea, clear soup with green leaves, tastes fresh and refreshing, with faint fragrance, bean fragrance, chestnut fragrance and faint apple fragrance.

Black tea, red leaf soup, has a mellow and sweet taste, and the aroma is floral or fruity, such as honey, potatoes, longan and so on.

The difference in quality stems from the difference in their composition.

Among water-soluble flavor substances, green tea contains more catechins (astringent taste) and caffeine (bitter taste). The content of water-soluble polysaccharide in black tea is relatively high. Among the volatile aroma substances, green tea is mainly characterized by linalool, geraniol, jasmonate and similar substances. These compounds have an aromatic smell and make great contributions to green tea. Black tea mainly contains hexanal, damascenone and other components, and the volatile substances have sweetness, tropical fruit fragrance and rose fragrance.

The respective health advantages of green tea and black tea.

Different ingredients, both have their own advantages in health care.

Green tea and catechin have excellent antioxidant capacity. Catechin has the health-care functions of lowering blood sugar, lowering blood fat, lowering blood pressure, scavenging free radicals, sterilizing, delaying aging and resisting cancer. At present, catechin is recognized by the world as "the most ideal anticancer substance extracted from natural plants after paclitaxel".

Black tea and tea polysaccharide have important application value. Among them, active polysaccharides have unique physiological activities and pharmacological effects in preventing cardiovascular diseases and enhancing immunity. Due to the fermentation process of black tea, astringent tea polyphenols form many mild oxidation products, so it has little stimulation to the stomach and the tea is mild.