Green killing technology of long fried green tea
Green tea in China can be divided into four categories according to the manufacturing methods: roasted green tea, baked green tea, steamed green tea and sun dried green tea. Among them, fried green tea is the most.
According to the final form, the green tea can be divided into long fried green tea, round fried green tea, flat fried green tea and so on. Among them, the most famous green tea is long fried green tea.
For each producing area, although the specific processing of long fried green tea is not exactly the same, but the main process is the same, there are four processes: green, rolling, deblocking, screening, drying. Among them, cyaniding is the key process. Today, let’s introduce the technology of killing green tea.
There are four purposes to kill the green
(1) The enzyme activity in fresh leaves was destroyed rapidly by high temperature, and the enzymatic oxidation of polyphenol compounds was stopped to keep the tea green.
(2) Using high temperature to promote the volatilization of low boiling point aromatic substances, emit grass gas, and develop rich tea fragrance.
(3) It can accelerate the hydrolysis and pyrolysis of chemical components in fresh leaves, and lay a foundation for the formation of final quality of green tea.
(4) Evaporation part of the water, so that leaves become soft, increase toughness, easy to roll molding.
There are two principles to be followed in the process of killing
(1) High temperature, first high and then low
When the temperature reached 70 ℃, the enzymes in fresh leaves began to be inactivated; when the temperature rose to 80 ℃, almost all the enzymes were denatured in a short time; when the temperature was close to 100 ℃, almost all the enzymes lost their catalytic effect in an instant. Therefore, the leaf temperature should be raised to above 80 ℃ at the early stage of green removal, so as to effectively prevent the production of red stem and red leaf.
However, the continuous high temperature is not good for the quality of tea, which will cause more chlorophyll to be destroyed and the leaf color will turn yellow; the tea will produce burnt spots and explosion points, the tip of tender buds and the edge of fresh leaves are easy to be scorched, and the tea will produce burnt tobacco flavor. Therefore, in the high temperature sterilization, we must also achieve “first high and then low”. In this way, the fresh leaves can be killed evenly and thoroughly, and they are old but not burnt and tender but not born.
(2) Young leaf old kill, old leaf young kill.
The meaning of “nensha” means that the time to kill green leaves should be shorter and the water loss of leaves should be less. The meaning of old killing is the opposite.
The reason why the tender leaves need to be killed is that the tender leaves have high water content, strong enzyme activity, strong toughness and strong viscosity. Proper old killing is conducive to improving the quality.
The moisture content of old leaves is low, and the enzyme activity is relatively low. It is beneficial to form the stripline and reduce the broken tea.
To what extent is the most appropriate?
The degree of cyaniding mainly depends on the tea maker’s experience and senses. It is too tender, there are many pieces of broken tea after rolling, the shape is poor, the aroma is green, and the taste will be astringent; if it is too old, there are more tea leaves after rolling, which is difficult to form strips, and it is easy to produce burnt tobacco flavor.
In general, the weight loss rate of fresh leaves after sterilization is about 40%, which is basically in the most appropriate degree. The weight of fresh leaves of 100 kg is about 63 kg, and the moisture content of the leaves is about 60%.
From the feel of the hand, it can be squeezed into a ball, slightly elastic, and the tender stem is not easy to break; from the color, the color is dark green, and the leaf surface is tarnished.