Tea Encyclopedia

Before 1990s, all levels of Fujian oolong tea required sufficient brewing time. After the 1990s, in order to meet the market demand, generally, varieties of Minnan oolong tea have a slightly lighter requirement for super-duration, the first-class duration is lighter, the second-class duration is more sufficient, the third-class duration is more sufficient, and the fourth-class duration is more sufficient. All levels and varieties of oolong tea in northern Fujian require high-grade tea, and low-grade tea is sufficient.

The level of pyrotechnics depends on the degree of baking. Liang Zhangju, a tea man in Qing Dynasty, once praised the baking skills of rock tea: "Wuyi baking method is the best in the world". So far, as far as the baking technology of major tea varieties is concerned, there is really no tea baking technology that can surpass rock tea.

First, the role of the fire

Historically, the main purpose of baking rock tea was to preserve it. In the past, when roasting fire, it was necessary to calculate the travel time of rock tea to the sales area and the time of selling tea to determine the degree of fire treatment. If the new rock tea is listed in the sales area, the pyrotechnics have just retired and the tea has not turned green after being sold out, then this pyrotechnics is the best treatment.

At present, the purpose of the fire is mainly manifested in the following five aspects:

1. Evaporating water to prolong the shelf life: Tea leaves have a loose structure and many components with hydrophilic groups such as hydroxyl groups, which have strong hygroscopicity, so the water content of tea leaves is below 5%. When the water content of tea reaches 12%, mold begins to appear, and the tea will gradually become moldy and deteriorate, thus losing its drinking value.

2, sterilization, reduce pesticide residues: there are microorganisms in tea, including mold, mushrooms, yeast. Mold is a sign of mildew and pollution of tea. Generally, it can kill mold above 160 degrees. In addition, tea leaves containing pesticide residues can be degraded and volatilized at high temperature to reduce residues.

3. Blending raw materials: After the tea blending raw materials are dried, the aroma of various varieties and paths of tea can be unified, which plays the role of mixing and blending.

4. Improve the aroma and change the quality: the first tea is often accompanied by foul green taste, bitter taste, peculiar smell and stale taste caused by improper storage, so baking at a certain temperature can make the tea taste pure, increase the freshness and restore the fire taste.

5. Enhance the fragrance and familiarity to meet the different tastes in the sales area: rock tea pays attention to' slow fire and slow baking' and requires full cooking without exposure to the sun to set off the rock rhyme.

Second, the principle of warming fire

Some data show that charcoal has super adsorption capacity because of its unique structure, which can automatically adjust humidity, adsorb and decompose odor, and deodorize harmful chemicals such as sulfide, hydride, methanol, benzene and phenol. The negative ions generated by it have penetrating ability, which can purify the air and improve the air quality. Far infrared rays emitted by charcoal can make objects generate slight heat. The quality of traditional charcoal-baked tea is far superior to that of modern machine-baked tea. As far as biochemical knowledge is concerned, the main principles of baking process include:

1. Dehydration and saccharification (ripening): In the baking process of rock tea, sugars, amino acids and pectin can be dehydrated and converted into aroma components, so it has caramel fragrance and honey fragrance.

2. Isomerization: The heat of baking makes most of the low-boiling substances with green gas volatilize and dissipate, which makes catechins produce isomers and increases the contents of free catechins and trans-geraniol. This reaction can make up for some defects of the previous process and make the taste better.

3. Oxidation: the roasting of rock tea promotes the oxidative decomposition of catechins, aldehydes and alcohols and the combination of amino acids to become fresh fragrance, forming a new technological aroma. Heat promotes the oxidative transformation of tea pigment, which has a good influence on the color, leaf bottom and soup color concentration of finished tea. Therefore, in the last few minutes of full fire, we should not lack oxygen. After baking, the tea leaves should be ventilated and cooled in time to ensure sufficient oxygen supply, and the cooling time should not be too long, otherwise a lot of bland taste and aroma of water will be lost.

4. Post-ripening: that is, the process of drying and packaging tea while it is hot until the quality does not appear stale is called "post-ripening". After-ripening quality is closely related to the water content of tea, storage conditions and the change degree of effective chemical components in tea. In order to obtain good after-ripening effect, the water content of tea in storage should be controlled at 6%-8%.

Third, the technical requirements of baking fire

The actual function of heat is the degree of thermophysical and chemical action in tea. Heat will affect the appearance color, leaf bottom soup color and foam resistance. Proper cooking can make up for some shortcomings of tea quality, while improper cooking will reduce the quality of rock tea, even make it burnt, so smart tea roasters can use baking technology to improve the quality of tea to a higher level. Special varieties of tea, the temperature is just right, can set off a special fragrance and rhyme characteristics, commonly known as "tea is king, fire is minister, and monarch and minister are auxiliary." That's the truth.

Tea baking is always better to "stew slowly". The principle is that the higher the tea, the longer it takes to bake at low temperature, while the temperature of low-grade tea and tea head can be appropriately higher. When the charcoal stove is just lit, the temperature is high and the smell is unpleasant. It is often used to dry tea heads and low-grade tea leaves. The medium-term temperature is low and stable, and it is often used to bake high-grade tea. If the fire temperature is too high, the aromatic oil of tea will volatilize too much. The fixation is weakened, the aroma is reduced, and at the same time, over-heating, some soluble substances will be transformed into insoluble substances, which will dim the appearance and color of tea, make the taste of tea soup weak, and the weight will be burnt and lose its aroma. Practice also shows that the formation of honey aroma and other aroma of tea often occurs in the process of long-term baking at low temperature, which also promotes the coking of sugar and produces the aroma of maltose.

The smell of fire can cover up many advantages and disadvantages of rock tea, so when drinking rock tea, the higher the baking degree, the better. The best situation should be that there is a smell of fire without anger. The lower the roasting degree, the yellow-green appearance, the higher the aroma, the fresher the taste, the yellowish tea soup, and sometimes turbid (clarified after the whole fire), and the brighter the leaf bottom. The higher the baking degree, the longer the aroma, the mellow and smooth the taste, the orange-red color of the soup and the deeper the leaves.

Fourth, the degree of fire.

The degree of roasting should be mastered according to the basic characteristics of tea, the habits of sales areas and the special needs of consumers. As for the basic characteristics of tea, we should pay attention to different varieties, different seasons, different regions, different fermentation degrees, different grades and different water contents. Different thicknesses of raw materials have different degrees of heat of new and old teas. Usually, tea with better intrinsic quality is more resistant to baking.

Therefore, it is not accurate to simply divide the fire power of rock tea into light fire, medium fire and big fire according to the baking time. Traditional rock tea baking is commonly known as "foot fire" The most basic requirement of baking is to watch tea baking, that is, to let tea eat through the fire. For traditional rock tea, the sign of eating through fire is the appearance of "toad skin", so it may be more appropriate to call a tea "foot fire" as long as it has been eaten too much.

Attachment: Wuyi Rock Tea "Toad Back"

Speaking of Wuyi rock tea, we often talk about the word "toad back". Many friends are puzzled by the word "toad's back" Toad back, in fact, is a frog-skin-like white bubble formed by Wuyi rock tea after a long period of fire baking, so there will be no toad back with fragrant rock tea. It is because of repeated baking that the inside of tea burns completely, and bubbles overflow from the inside of tea, holding up bubbles one by one. After soaking, look at the bottom of the leaves and you can easily find the toad's back foot fire rock tea.

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