One, the production process of green tea

The processing of green tea is simply divided into three steps: killing, kneading and drying, of which the key lies in the first process of initial production, namely, killing. Fresh leaves through the greening, the enzyme activity is blunted, containing a variety of chemical compositions, basically in the absence of enzyme influence conditions, the physical and chemical changes by the action of heat, thus forming the quality characteristics of green tea.

(1) greening

Greening plays a decisive role in the quality of green tea. Through high temperature, destroy the enzyme properties of fresh leaves, stop the oxidation of polyphenols to prevent the leaves from reddening; at the same time, evaporate some of the water in the leaves, make the leaves soft, and create conditions for kneading and shaping. With the evaporation of water, fresh leaves with grass gas in the low-boiling point aromatic substances volatilization disappeared, so that the aroma of tea has been improved. Factors affecting the quality of greening are greening temperature, the amount of leaves, the type of greening machine, time, greening method.

(2) Twisting

Twisting is a process of shaping the appearance of green tea. Through the use of external force, so that the leaf kneading broken light, rolled into a strip, volume reduction, and easy to brew. At the same time part of the tea juice squeeze overflow attached to the surface of the leaf, to improve the concentration of tea flavor also has an important role.

The green tea kneading process has a cold kneading and hot kneading. The so-called cold kneading, that is, after the green leaves are cooled and kneaded; hot kneading is not cooled and kneaded while the green leaves are hot. Young leaves should be cold kneaded to maintain the bright yellow-green soup color on the bottom of the young green leaves, and old leaves should be hot kneaded to facilitate the tightening of the rope and reduce the fragmentation.

(3) Drying

The purpose of drying is to evaporate the water and organize the shape to give full play to the fragrance of the tea.

Drying methods, there are three forms of drying, frying and sun drying. The drying process of green tea, generally after drying, and then stir-fry dry. Because the tea after kneading, the water content is still very high, if the direct frying dry, will be in the frying dryer pan quickly into lumps, tea juice is easy to adhere to the walls of the pan. Therefore, the tea leaves are dried first, so that the water content is reduced to meet the requirements of the pan frying.

Two, the production process of black tea

China's black tea, including black tea, black tea and black tea, its method is similar, have withering, kneading, fermentation, drying four processes. The quality characteristics of all kinds of black tea are red soup and red leaves, the formation of color and aroma are similar to the process of chemical changes, only the conditions of change, the degree of difference.

(1) Withering

Withering refers to the fresh leaves after a period of water loss, so that a certain degree of hard and brittle stalks and leaves into the wilting and withering condition of the process, is the first process of the initial production of black tea. After withering, the water can be properly evaporated, the leaves are soft, toughness enhancement, easy to shape.

(2) kneading

The purpose of black tea kneading is the same as that of green tea, the tea leaves are shaped in the process of kneading and enhance the concentration of color and aroma, and at the same time, due to the destruction of the leaf cells to facilitate the oxidation of enzymes under the action of the necessary for the smooth progress of fermentation.

(3) Fermentation

Fermentation is a unique stage in the production of black tea, after fermentation, the color of the leaf changes from green to red, forming the quality characteristics of black tea red leaves and red soup.

The mechanism is that the leaves in the role of kneading, tissue cell membrane structure received damage, increased permeability, so that polyphenols and oxidative enzymes in full contact with the enzyme under the action of oxidation polymerization, and other chemical components are also corresponding to the occurrence of profound changes in the green tea leaves to produce a red change in the formation of the black tea color and aroma qualities.

(4) Drying

Drying is the process of fermented tea billet, using high temperature baking, rapid evaporation of water to achieve the quality of dryness.

The purpose is threefold: the use of high temperature to rapidly passivate enzyme activity, stop fermentation; evaporation of water, reduce the volume, fix the shape, maintain the dryness in order to prevent mold and mildew; most of the low-boiling point of the grassy smell, agitation and retain the high-boiling point of the aromatic substances, to obtain the unique sweet aroma of black tea.

Three, oolong tea production process

Oolong tea manufacturing, the process can be summarized as follows: withering, greening, stir-frying, kneading, drying, of which greening is the formation of oolong tea characteristics of the unique quality of the key processes, is to lay the foundation for oolong tea aroma and flavor.

(1) Withering

Withering is the cool green and sunshine green referred to in Oolong tea area. Through withering, part of the water is released to improve the toughness of the leaves, which is convenient for the subsequent processes; at the same time, along with the process of water loss, the enzyme activity is enhanced, and part of the grass is released, which is conducive to the disclosure of the aroma.

(2) Doing green

Doing green is an important process in the production of oolong tea, the special aroma and green leaves with red edges are formed in doing green.

(3)Stir-frying

The inner quality of oolong tea has been basically formed at the stage of greening, and stir-frying is the turning process, which is like the greening of green tea, and mainly inhibits the enzyme activity in the fresh leaves, controls the oxidation process, prevents the leaves from continuing to redden, and fixes the quality of the greening process. Secondly, it is the volatilization and transformation of low boiling point green grass gas to form the fragrance of tea. At the same time through the role of moisture and heat to destroy part of the chlorophyll, so that the leaves are yellow-green and bright. In addition, it also volatilizes part of the water, making the leaves soft and easy to knead.

(4) kneading

The role is the same as green tea.

(5) drying

Drying can inhibit enzymatic oxidation, evaporation of water and soften the leaves, and play a role in thermalization, eliminating bitterness and astringency, and promote the taste mellow.

Four, the production process of white tea

White tea is a specialty of China, one of the six major types of tea, mainly produced in Fujian Province. The production process of white tea is generally divided into withering and drying two processes, and the key lies in withering.

(1) Withering

Withering is divided into indoor natural withering, compound withering and heating withering.

(2) drying

Drying can be used to dry (natural drying), drying two kinds of processes.

Fifth, yellow tea production process

Yellow tea quality is characterized by yellow soup and yellow leaves, the system is mainly characterized by smothering the yellow process, the use of high temperature killing to destroy the enzyme activity, and its oxidation of polyphenol substances is due to the action of heat and humidity and produces some colored substances. The degree of discoloration is light, is yellow tea, the degree of heavy, the formation of black tea. Its typical process is killing, smothering yellow, drying, kneading is not an essential process of yellow tea.

(1)Killing

Yellow tea through the killing, in order to destroy the enzyme activity, evaporate part of the water, dissemination of green grass gas, the formation of aroma has an important role.

(2) smothered yellow

Smothered yellow is the yellow tea manufacturing process is characterized by the formation of yellow yellow yellow soup is the key process. From greening to the end of drying, can create appropriate moist heat process conditions for the yellowing of tea, but as a tea manufacturing process, some tea in the greening after smothering yellow, and some in the wool fire after smothering yellow, some smothering and frying alternately.

The factors that affect the smothering of yellow are mainly the water content of tea and leaf temperature. More water content, the higher the leaf temperature, the yellowing process under hot and humid conditions is also faster.

(3) drying

The drying of yellow tea is generally divided into several times, and the temperature is also lower than other types of tea.

Sixth, the production process of black tea

The manufacturing process of black tea for killing, kneading, stacking, drying. One of the black tea manufacturing process is unique, but also the formation of black tea quality of the key process.

(1)Killing

Because the leaves of black tea are coarse and old, with low water content, they need to be fried at high temperature and turned quickly and evenly, and can be dark green.

(2)Kneading

After the green leaves come out of the pot, they are immediately kneaded and twisted while they are hot, which is easy to shape a good appearance. The kneading method is the same as the general black and green tea.

(3) Ovation

The twisted leaves, stacked square on the gabion, 15 to 25 cm thick, covered with a wet cloth, and add a cover to moisturize and heat preservation, Ovation process. Wo heap in progress, should be based on the heap temperature changes, timely turning 1 ~ 2 times.

On the substance of the chemical changes in the Ottawa, there is no conclusive evidence, the current tea industry has an enzyme, microbial action and moist heat effect of the three doctrines, but it is generally believed to play a major role in the role of hydrothermal effect, and the yellow tea smothering yellow process is similar.

(4) drying

There are baking method, sun-drying method, in order to fix the quality and prevent deterioration.