How to process tea

Tea processing technology

Brief introduction of six tea making processes;

(A) green tea manufacturing process

The processing of green tea can be simply divided into three steps: enzyme fixation, rolling and drying, among which the key lies in the first process of primary production, namely enzyme fixation. Fresh leaves are inactivated by enzyme activity, and the chemical components contained in them are basically unaffected by enzymes, and change through heat, thus forming the quality characteristics of green tea.

(1) fixed

Immobilization plays a decisive role in the quality of green tea. Through high temperature, the characteristics of enzymes in fresh leaves are destroyed, the oxidation of polyphenols is stopped, and the leaves are prevented from turning red; At the same time, some water in the leaves is evaporated, which makes the leaves soft and creates conditions for kneading and shaping. With the evaporation of water, the low-boiling aromatic substances in fresh leaves evaporate and disappear, thus improving the aroma of tea.

Except for the special tea, the process is carried out in the green-fixing machine. The factors that affect the quality of enzyme fixation are enzyme fixation temperature, leaves left, enzyme fixation machine type, enzyme fixation time and enzyme fixation method. They are a whole, interrelated and restricted.

(2) Kneading

Kneading is a process of shaping the shape of green tea. Using external force, the leaves are crushed and lightened, rolled into strips, reduced in size and convenient for brewing. At the same time, some tea juice overflows and adheres to the surface of leaves, which also plays an important role in improving the taste concentration of tea.

The rolling process of making green tea can be divided into cold rolling and hot rolling. The so-called cold kneading is to spread the green leaves and roll them up; Hot rolling is to roll the leaves while they are still hot, and don't scatter them. The tender leaves should be cold-kneaded to keep the bright yellow-green soup color at the bottom of the tender green leaves, and the old leaves should be hot-kneaded to facilitate close knot and reduce fragments.

At present, the kneading operation of bulk green tea has been mechanized, except for the famous and excellent tea which is still operated by hand.

(3) drying

The purpose of drying is to evaporate water, tidy up appearance and give full play to tea fragrance.

There are three drying methods: sun drying, frying and drying. In the drying process of green tea, it is usually dried first and then fried. Because the water content of the twisted tea leaves is still very high, if fried directly, lumps will quickly form in the pot of the frying machine, and the tea juice will easily stick to the pot wall. Therefore, tea leaves should be dried first to reduce the water content to meet the requirements of pot frying.

(2) black tea manufacturing process

China's black tea includes Kung Fu black tea, black broken tea and small black tea. The production methods are similar, and there are four processes: withering, rolling, fermentation and drying. The quality characteristics of all kinds of black tea are red soup and red leaves. The formation of color, aroma and taste has a similar chemical change process, but the conditions and degrees of change are different. Let's take Kung Fu black tea as an example to briefly introduce the production process of black tea.

(1) withered

Withering refers to the process that fresh leaves lose water for a period of time, making some hard and brittle stems and leaves wither and wither. This is the first process of black tea preliminary production. After withering, the water can be properly evaporated, and the leaves are soft, the toughness is enhanced, and the shape is convenient. In addition, this process is an important processing stage to form the aroma of black tea, which makes the grass fragrance disappear and the tea fragrance appear. There are two ways of withering: natural withering and trough withering. Natural withering is to spread the tea thinly indoors or outdoors where the sun is not too strong, and leave it for a certain time. Withering trough withering is to put fresh leaves in a ventilation trough and introduce hot air to speed up the withering process, which is a common withering method at present.

(2) Kneading

The purpose of rolling black tea is the same as that of green tea. Tea leaves are shaped in the process of rolling, and their color, taste and concentration are enhanced. At the same time, because the leaf cells are destroyed, it is convenient for the necessary oxidation under the action of enzymes, which is conducive to the smooth progress of fermentation.

③ Fermentation

Fermentation is a unique stage in the production of black tea. After fermentation, the color of leaves changed from green to red, forming the quality characteristics of red leaves and red soup of black tea. The mechanism is that the cell membrane structure of tissues is destroyed under the action of leaf rolling, and the permeability is increased, so that polyphenols are fully contacted with oxidase, and oxidative polymerization occurs under the action of enzyme, and other chemical components also undergo profound changes accordingly, which makes green tea turn red and forms the color, fragrance and quality of black tea. At present, fermentation machines are widely used to control the temperature and time of fermentation. Moderate fermentation, the color of young leaves is red and uniform, the old leaves are red and blue, the smell of grass disappears, and there is the fragrance of mature fruits.

(4) drying

Drying is the process of baking the fermented tea blank at high temperature to make the water evaporate quickly and achieve dry quality. It has three purposes: using high temperature to quickly inactivate the activity of enzyme to stop fermentation; Evaporate water, reduce volume, fix appearance, keep dry and prevent mildew; Emit most of the low-boiling grass fragrance, strengthen the retention of high-boiling aromatic substances, and obtain the unique sweetness of black tea.

(3) the production technology of oolong tea

The production process of oolong tea can be summarized as: withering, deactivating enzymes, frying, kneading and drying. Among them, water fixation is the key process to form the unique quality characteristics of oolong tea, and it is the basis to lay the aroma and taste of oolong tea.

(1) withered

Withering refers to cool green and sun green in oolong tea area. Through withering, some water is released, which improves the toughness of the leaves and is convenient for subsequent processing; At the same time, with the process of water loss, the activity of the enzyme is enhanced, and some grass gas is emitted, which is beneficial to the disclosure of aroma.

The particularity of oolong tea withering is different from that of black tea. The withering of black tea not only has a large degree of water loss, but also the processes of withering, rolling and fermentation are carried out separately, while the withering and fermentation of oolong tea are not separated, but coordinated with each other. Through withering, through the change of water content to control the moderate transformation of substances in leaves, to achieve a suitable degree of fermentation. There are four ways of withering: cooling (indoor natural withering), drying (sunlight withering), baking (heating withering) and artificial control of withering.

(2) Do green environmental protection.

Green making is an important process in the production of oolong tea, in which the unique aroma and red edge of green tea are formed. After withering, the tea leaves shake in a shaker, and the leaves collide with each other, scraping the cells at the leaf edge, thus promoting enzymatic oxidation. After shaking, the leaves turn from soft to hard. After standing for a period of time, the oxidation is relatively slow, which makes the water in the petiole veins slowly spread to the leaves. At this time, the fresh leaves gradually expand, restore elasticity and soften the leaves. After such a regular and familiar dynamic and static process, tea has undergone a series of biochemical changes. Leaf margin cells were destroyed, slightly oxidized, and the leaf margin was red. In the center of the leaf, the color of the leaf changes from dark green to yellow-green, which is called "green leaf with red edge"; At the same time, the evaporation and movement of water are beneficial to the development of aroma and taste.

(3) Stir fry

The endosperm of oolong tea has basically formed in the green period, and frying green tea is a transitional process. Like green tea, it mainly inhibits the activity of enzymes in fresh leaves, controls the oxidation process, prevents the leaves from turning red and fixes the quality of green tea. Secondly, the volatile transformation of low-boiling grass gas forms a strong tea fragrance. At the same time, some chlorophyll is destroyed by damp heat, which makes the leaves yellow-green, bright in color. In addition, some water can be volatilized to make the leaves soft and easy to rub.

(4) kneading

Its function is the same as that of green tea.

(5) drying

Drying can inhibit enzymatic oxidation, evaporate water, soften leaves, and play a role in heating, removing bitterness and promoting alcohol.

(4) white tea making process

White tea is a specialty of our country, mainly produced in Fujian Province. The dry tea surface of white tea is densely covered with white velvet, and its quality characteristics are formed by picking many tender leaves and adopting a drying process without frying or kneading.

At present, there are not many kinds of white tea, including bud tea (white silver needle) and leaf tea (such as tribute eyebrow), and the production process is simple.

The production process of Baihao Yinzhen is as follows: tea bud, withering, baking, screening, reheating and packaging.

Bai Mudan, Gongmei technology: fresh leaves, withering, baking (or drying in the shade), picking (or screening), reheating and packaging.

(5) Yellow tea production technology

The quality of yellow tea is characterized by yellow soup and yellow leaves. The production method is mainly characterized by the yellowing process, which destroys the activity of enzymes through high temperature inactivation, and then the hot and humid heat leads to the oxidation of polyphenols and produces some colored substances. The lighter discoloration is yellow tea, and the heavier discoloration is black tea.

Its typical technological process is enzyme fixation, yellowing and drying, and kneading is not an essential process of yellow tea.

(1) fixed

Yellow tea plays an important role in the formation of aroma by deactivating enzymes, evaporating some water and emitting grass gas.

(2) stuffy yellow

Kneading is the characteristic of the production process of yellow tea, and it is also the key process to form yellow soup. From the end of enzyme fixation to the end of drying, suitable wet and hot technological conditions can be created for tea yellowing. However, as a tea-making process, some teas are stuffy yellow after fixation, some are stuffy yellow after fire, and some are stuffy and fried alternately. According to different tea quality, there are different methods, but all the ways lead to the same goal, all in order to form the good quality characteristics of Huanghuang Decoction.

The main factors affecting stuffy yellow are the water content and leaf temperature of tea. The higher the water content, the higher the leaf temperature, and the faster the yellowing process under hot and humid conditions.

(3) drying

Yellow tea is usually dried several times, and the temperature is lower than other teas.

(6) the production process of black tea

The production process of black tea is enzyme fixation, rolling, composting, fermentation and drying. Among them, pile fermentation is a unique process in the production of black tea and a key process to form the quality of black tea.

(1) fixed

Because the tea picked by black tea is thick and old, with low water content, it needs to be fried quickly at high temperature and turned quickly and evenly into dark green.

(2) Kneading

After the water-fixing leaves are out of the pot, they are immediately rubbed while they are hot, which is easy to shape a good shape. The rolling method is the same as that of ordinary red and green tea.

(3) Stacking fermentation

Pile the twisted leaves on a mat with a thickness of 15 ~ 25 cm, cover them with a wet cloth, and cover them with an object for moisture preservation and heat preservation, so as to carry out the composting and fermentation process. In the process of heap fermentation, according to the change of heap temperature, it is necessary to turn the heap 1 ~ 2 times.

At present, there is no conclusion about the nature of chemical changes in bulk fermentation. At present, there are three theories in tea industry: enzyme action, microorganism action and damp-heat action, but it is generally believed that hydrothermal action plays a major role, which is similar to the yellowing process of yellow tea.

(4) drying

There are baking and drying methods to fix the quality and prevent deterioration.

Processing flow:

Spreading fresh leaves-fixing-spreading and cooling-rolling-finishing-primary drying-spreading and cooling-fire

First, spread the fresh leaves.

After the fresh leaves are sent to the tea factory, they should be spread out in time and divided into three parts: 1, and the fresh leaves of different varieties should be separated; 2. Leaves should be separated in sunny and rainy days; The fresh leaves picked in the morning should be separated from those picked in the afternoon.

Spreading tools: Fresh leaves should be spread on soft plaques or bamboo mats.

Spreading thickness: the best fresh leaves: spreading thickness is not more than 3 cm; Ultra-fresh leaves: the spreading thickness is not more than 5 cm; Ordinary fresh leaves: the spreading thickness shall not exceed 10cm.

Spreading time: generally, it is spread for 6 hours-12 hours, and it is gently turned every 2 hours. Rain leaves and exposed leaves can be dehydrated by fan or fresh leaf dehydrator.

Degree of spreading: the leaves are soft, the buds are stretched, and the water is scattered, which can make incense.

Second, watch.

Adopt multifunctional famous tea machine or miniature roller machine.

Pot temperature: the temperature of the tank reaches 150℃-200℃.

Leaf dosage: 0.75 kg- 1 kg per pot, that is, 0. 15 kg-0.2 kg per pot, and the dosage of 30-type drum dewatering leaves is 30kg per hour.

Time: When using multifunctional enzyme deactivation, stir fry for 2-3 minutes, then stir fry at low temperature for 2-3 minutes and 5-6 minutes.

Degree: The leaf color turns dark green, the leaf quality is soft, the stalk is constantly broken, there is no green gas, no scorched edge and no red leaves, and the tea fragrance is moderately revealed.

Third, spread cold: after the water-fixing leaves are out of the pot, they should be spread evenly on the bamboo mat immediately, so that they can emit hot air and cool as soon as possible to keep green and not produce heat and sulk. Duration 10 minutes-15 minutes.

Fourth, knead

Kneading can be carried out by hand or by type 25 or 30 kneader. Hand shaking: Hold two pots of water-removing leaves in the palm of your hands and rub them in one direction, with a light gesture. Then shake the tea balls evenly, spread them evenly on a small bamboo mat, and pat them with your palm to shape. Repeat for three times until the tea stick becomes straight and the tea is full of fragrance, lasting 1-2 minutes.

Fifth, management rules

When the pot temperature rises to 100℃, the twisted leaves can be put in 0.5 kg-0.75 kg, and the rope is kept slow for 2-3 minutes. When the rope becomes straight and tight, take it out of the pot and cool it. When using the carding machine, the leaf quantity, slot temperature and time should be operated according to the requirements of the machine.

Sixth, the first baking

Dry with electric heating or micro dryer or 60 tea dryers. Temperature: When the temperature of the dryer reaches 100℃- 120℃, start feeding leaves. Thickness: spread the trimmed leaves evenly on the drying net, and the thickness shall not exceed 1cm. Requirements: rotate once every 2-3 minutes, and the upper and lower drying nets rotate in turn. Time: lasting about 10 minutes-15 minutes. Degree: Baked to 70% dry, the leaves can produce a little tentacle.

7. Spread cool and regain moisture: spread the freshly dried tea leaves on a soft board and spread cool and regain moisture. Time 15 minutes.

Eight, foot fire

Dry with a micro dryer or a famous tea baking machine. Temperature: 80℃-90℃. Thickness of spreading leaves: combine two pieces of first-sun leaves and spread them evenly on the drying net. Requirements: Turn it every 2 minutes until the feet are dry, pick the strongest buds, twist the powder with your fingers, and then bake. The whole journey takes about 15 minutes -20 minutes.

9. Sieving and packaging: pour the dried tea leaves into a floppy disk, cool it slightly, sieve it to remove powder, and seal it for storage.