"Protecting enzyme" and "inactivating enzyme"

Yunnan Pu 'er tea and green tea are both fried green, but the technology is completely different, mainly because Yunnan Pu 'er tea is fermented and green tea is not drunk at all, so the technology can be summarized as "enzyme preservation" and "enzyme inactivation".

Green tea: Generally, green tea is "three greens" (color green, soup green and leaf bottom green). Usually, green tea is immobilized at a high temperature with a leaf humidity above 75C, which is stuffy and impenetrable, and sometimes it has to be "re-fried" to completely destroy the activity of polyphenol oxidase, prevent it from degrading chlorophyll, block the possibility of later fermentation, and make the leaves bright green and have a high aroma.

Pu'er tea

Pu 'er tea has complex components, so it is necessary to destroy most of the activities of polyoxometalate oxidase, prevent excessive oxidation of polyphenols and keep some enzymes, so that fresh leaves will not be drunk after normal operation. In addition, the deactivation of Pu 'er tea also undertakes the functions of further degrading chlorophyll (ensuring bright apricot color in the soup and fresh and green leaves at the bottom), weeding fishy smell (ensuring the appearance of tea fragrance) and evaporating water (making tea soft and easy to knead and shape).

Technical points of enzyme immobilization

Inactivation is not only important, but also relatively difficult, among which temperature is the most difficult to control, because the enzyme in fresh leaves is a very sensitive existence, and its activity will constantly change with the temperature of leaves.

temperature

If the temperature is not enough, the enzyme protein of fresh leaves will denature and become suspicious, which will lead to the enhancement of polyphenol oxidase activity and enzymatic oxidation, which will transform colorless tea polyphenols into red oxides, that is, "red leaves".

If the temperature is too high, the protein of fresh leaf enzyme will solidify faster, which will lead to the complete inactivation of polyphenol enzyme and turn it into a green tea process. Moreover, tea green will be burnt, burst or even scorched, which is called "smoke-burnt tea".

Mainly manifested in the following laws:

When the leaf temperature is higher than 20℃, the tea enzyme activity increases gradually.

When the leaf temperature is 40 ℃~ 45℃, the tea enzyme activity reaches the extreme value.

When the leaf temperature is higher than 45℃, the tea enzyme activity is gradually passivated.

When the leaf temperature is higher than 65℃, the activity of tea enzyme is basically lost.

In order to reach the temperature of Yuzryha residue, the pot temperature of artificial deactivation of Pu 'er tea generally needs to be controlled below180 "C. However, few people used a thermometer to measure the deactivation temperature before, and everyone mastered it by experience.

Looking at the temperature of the pot, there is a summary of the so-called "dark gray during the day and dark red at night". More experienced masters will listen to the temperature of fresh leaves in the pot. If you can't hear the thump of tea in the pot, there will be red hearts and leaves, most likely a strong grass flavor.

Moisture/water content

The climate, rainfall, tea green grade and tea quality are different every year. Therefore, manual fixation should follow a very important principle: watch tea and make tea.

There are many ways to treat rainwater tea in spring. Generally, the moisture content of fresh dew leaves picked in the morning is about 20%, while the moisture content of fresh dew leaves picked in rainy days is as high as 40%. Therefore, it is necessary to increase the heat when fixing the water, so that the water in the leaves can volatilize normally.

In order to avoid adhesion of leaves and smooth de-enzyming, water leaves should be properly extended to promote dehydration: the pot temperature should be appropriately increased, the amount of reported leaves should be reduced, and the heat should be guaranteed: take 100 kg of fresh leaves as an example, every 5% increase in water content of fresh leaves will increase by 2%~3% during de-enzyming.

skill

"tender-killing": under the same leaf temperature, the water-killing time is short and the water evaporation of fresh leaves is less. Old leaves have low water content and weak enzyme activity. Proper enzyme fixation can reduce broken tea and is also beneficial to molding.

"Old killing": Under the condition of the same leaf temperature, the fresh leaves will evaporate more water if the fixing time is long. Young leaves have high water content, strong enzyme activity, high toughness and easy adhesion, and proper aging is beneficial to molding.

"suffocate": the method of controlling temperature and humidity, covering passivated steel and keeping steam and heat as much as possible is "suffocate".

"Completely deactivating enzymes": uncover and shake the tea leaves, so that the temperature in the pot is getting lower and lower, and the method of reducing steam is "completely deactivating enzymes".

There is a so-called "quick, stuffy and thorough" method when fixing the green tea of Pu 'er tea, that is, fixing the green tea for two minutes first, keeping it stuffy for about one minute after the tea leaves are heated evenly, and uncovering it immediately after the steam rises from the pot. This method can stabilize the leaf temperature and avoid "smoky tea" and "red leaves"

It is precisely because of the difficulty and long time of manual enzyme fixation that it is mostly used as high-end Pu 'er tea in Chashan in recent years, while popular Pu 'er tea and professional primary production houses are gradually popularized, with higher efficiency and simpler temperature control.