Processing method of low-temperature brewing high-aroma high-amino-acid white tea

Abstract

The invention discloses a processing method of low-temperature brewing high-aroma high-amino-acid white tea, and belongs to the technical field of white tea processing. The preparation method comprises the following steps: primarily preparing white tea by adopting a compound withering method, withering the white tea for 12 hours in an indoor environment with the room temperature of 25 DEG C and the air humidity of 50-60%, then carrying out heating treatment by adopting a method of sunshine withering for 3-4 hours, then withering for 10 hours in a room again, reducing the moisture to 9%, stacking and boxing, carrying out primary baking after 7 days, and finally baking again after 1 month. According to the invention, the leaching rate of the white tea is improved through a compound withering method in primary processing of the white tea, control of parameters such as temperature control and humidity control and a baking technology in refining, and relatively good conditions such as melting and the like can be achieved under a low-temperature condition. The prepared Yunnan white tea is beautiful in appearance, has bud leaves connected with branches, is strong in pekoe, is rich in tea soup taste, is fresh and refreshing in taste, and has sweet and strong fragrance. Under the condition of low-temperature brewing, the content of tea polyphenol is relatively low, the fresh degree is kept high, and the taste is sweet and mellow, so that the quality of the Yunnan white tea is greatly improved.

Description

Technical Field

[0001] The invention relates to a method for processing low-temperature brewing high-fragrance and high-amino acid white tea, belonging to the technical field of white tea processing. Background Art

[0002] White tea is a slightly fermented tea and a special treasure among Chinese teas. It is named because the finished tea is mostly buds, covered with white hairs, like silver and snow. It is one of the six major types of tea in China. Due to the different varieties of tea trees and processing techniques, there are five famous white tea products: Baihao Yinzhen, Bai Mudan, Shoumei, Gongmei and new process white tea. The main production areas of white tea are Fuding, Zhenghe, Zherong, Tianshan, Songxi, Jianyang, Xinzhou Jiujie, Wuhan, Jinggu, Yunnan, etc.

[0003] Yunnan large-leaf white tea has the advantages of strong flavor and strong aftertaste, but it has a higher astringency when brewed at low temperature and has a low aroma. The consumer market demands white tea products with good freshness and strong aroma under low temperature and cold brewing conditions. The traditional white tea processing technology only includes withering and drying. At present, new technologies such as piling, light rolling, and light withering have been applied to white tea processing and have achieved good results. Yunnan white tea is generally processed by natural withering, sun drying, and shade drying. Due to the high temperature and low humidity of the withering tank, Yunnan white tea is prone to a state of micro-fermentation, with red changes and red stems. When brewed at low temperature, it is easy to have problems such as low concentration, high astringency, and low aroma.

[0004] According to analysis, the water extract of Yunnan large-leaf white tea is greater than 40-46%, and the water extract of a small number of ancient tree tea is greater than 50%. Compared with the white tea of ​​Fujian varieties with a higher market share, the aroma components are mainly floral, fruity, and honey. Fujian white tea is mainly hairy, woody, and honey, with a rich overall aroma and delicate floral fragrance. The caffeine content of Yunnan large-leaf white tea is slightly higher than that of Fujian tea, which has a natural variety advantage; while the amino acid content of Yunnan large-leaf white tea is 3-5%, and the freshness is slightly lower; the fat-soluble catechins contained in Yunnan large-leaf varieties account for a high proportion of catechins, so the astringency of Yunnan white tea soup is higher. Especially under low-temperature brewing, the freshness and aroma scores are lower than those of Fujian varieties. By consulting the existing technology, it can be seen that at present, improving the freshness of tea taste means increasing the amino acid content and reducing the tea polyphenol content, that is, reducing the phenol-ammonia ratio.

[0005] Yunnan white tea has good variety advantages and broad market consumption prospects. White tea with high freshness and fragrance is urgently needed in the market. Summary of the invention

[0006] 1. Technical issues to be resolved

[0007] The technical problem to be solved by the present invention is to solve the problems of small cell wall breaking, low tea soup extraction rate, high bitterness and low aroma of the existing Yunnan large-leaf white tea.

[0008] (2) Technical solution

[0009] To solve the above technical problems, the present invention provides a processing method for low-temperature brewing high-aroma and high-amino-acid white tea. The method initially processes white tea by using a compound withering method. After withering the white tea in an indoor environment at a room temperature of 25°C and an air humidity of 50%-60% for 12 hours, a temperature-raising treatment is carried out by using a sun-drying withering method for 3-4 hours, and then it is withered indoors again for 10 hours. After that, the moisture content drops to 9%, and it is piled up and packed into boxes. And after 7 days, primary baking is carried out, and finally, baking is carried out again after 1 month.

[0010] Furthermore, the processing method for low-temperature brewing high-aroma and high-amino-acid white tea includes the following steps:

[0011] S1. Picking: Select excellent Yunnan tea trees with good growth environments, appropriate picking times, and plump buds and leaves. Picking one bud with one leaf and one bud with two leaves of fresh leaves as raw materials. Put the freshly picked tea leaves in a shady place and collect the green tea with a breathable bamboo basket or bamboo crate.

[0012] S2. Compound withering: After withering the collected green tea in an indoor environment at a room temperature of 20-25°C and an air humidity of 50%-60% for 10-15 hours, a temperature-raising treatment is carried out by using a sun-drying withering method under sunlight with a temperature of 25°C-30°C for 3-4 hours, and then it is withered indoors again for 8-12 hours;

[0013] S3. Drying: Adopt a low-temperature slow-drying method for drying until the moisture content drops to 9%;

[0014] S4. Baking: Carry out primary baking on the dried tea leaves after 7 days, and finally carry out baking again after 1 month;

[0015] S5. Packing into boxes to complete the preparation of white tea.

[0016] Furthermore, in the step S1, after picking the fresh leaves, they need to be transferred to a shady place within 30 minutes, stored separately in bamboo baskets according to one bud with one leaf and one bud with two leaves. The thickness of the fresh leaves spread in the bamboo basket does not exceed 5 cm, and they are gently turned over every 30 minutes. Select a shallow-mouthed bamboo basket with a diameter ≤ 50 cm woven with thin bamboo strips and a porosity of 30%-40%.

[0017] Furthermore, in the step S1, the temperature of the green tea collection environment is controlled at 20-25°C, the relative air humidity is maintained at 65%-75%, and the total time from picking the fresh leaves to entering the withering process does not exceed 2 hours.

[0018] Further, in the step S2, after the harvested tea leaves are withered for 12 hours in an indoor environment at a room temperature of 20-25°C and an air humidity of 50%-60%, a temperature increase treatment is carried out by the method of sun withering for 3-4 hours under sunny weather at a temperature of 25°C to 30°C, and then withered indoors again for 10 hours.

[0019] Further, when withering, the thickness of the fresh leaves spread out is ≤2 cm, and they are gently turned over once per hour. The sun withering is carried out at 9:00-11:00 in the morning or 15:00-17:00 in the afternoon.

[0020] Further, during the first indoor withering, intermittent ventilation is combined, and the air is exchanged for 5 minutes per hour; during the second indoor withering, the temperature is reduced to 18-22°C and the humidity is increased to 65%-70%.

[0021] Further, in the step S3, temperature-controlled drying is carried out in stages; in the initial baking stage, a stepped temperature increase method is adopted, the initial temperature is set at 80-85°C, and it lasts for 30-40 minutes to initially evaporate the moisture to about 15%. During the process, the tea leaves are evenly spread on a bamboo baking tray with a thickness of ≤2 cm and turned over every 15 minutes; in the re-baking stage, the temperature is reduced to 60-65°C, the humidity of the drying environment is kept ≤30%, and the drying time is extended to 4-6 hours to slowly remove the remaining moisture to 9%.

[0022] Further, in the step S4, the initial roasting temperature is controlled within 70°C, and the roasting time is 3-4 hours; the re-roasting temperature is lower than 70°C, and the roasting time is 4-5 hours; and after re-roasting, flavor enhancement is carried out, the temperature is between 30-50°C, and the roasting time is 1 hour.

[0023] Furthermore, the initial roasting temperature is controlled at 60-65°C, and it is turned over every 30 minutes. After the initial roasting is completed, it is cooled and then enters the re-roasting. The re-roasting temperature is reduced to 50-55°C, and the environmental humidity is kept ≤40%.

[0024] (III) Beneficial effects

[0025] The above technical solution of the present invention has the following advantages:

[0026] The present invention is used to process and produce a white tea with a stable high leaching rate under low-temperature brewing, and greatly improves the freshness and aroma richness of the white tea. Through the initial processing links such as picking and compound withering, and after the programmed baking process, the leaching rate is increased, and the aroma is rich and has a high richness.

[0027] The present invention uses a compound withering method in the primary processing of white tea, adopts parameter control such as temperature and humidity control, and baking technology in the refining process to improve the leaching rate of white tea. And under low-temperature conditions, better dissolution conditions can be achieved. The Yunnan white tea produced has a beautiful appearance, the buds and leaves are connected, the bud hearts are plump, the taste of the tea soup is rich, fresh and refreshing, and the aroma is sweet and fragrant and rising. And under low-temperature brewing conditions, the content of tea polyphenols is low, maintaining the characteristics of high freshness and sweet and mellow taste, greatly improving the quality of Yunnan white tea. After many experiments, it is generally applicable to Yunnan large-leaf tea varieties and has high popularization potential.

[0028] The present invention is the first to use baking and compound withering technologies in Yunnan white tea. The prepared white tea has large cell wall breakage, high tea soup leaching rate, low bitterness and a rich aroma, forming a unique quality.

[0029] In addition to the technical problems solved by the present invention, the technical features of the technical solutions formed, and the advantages brought by these technical features of the technical solutions described above, the other technical features of the present invention and the advantages brought by these technical features will be further described in conjunction with the accompanying drawings. Description of the Drawings

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0031] Figure 1 It is a schematic diagram of the processing flow block diagram of the present invention. Detailed Embodiments

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0033] A processing method for high-aroma and high-amino-acid white tea brewed at low temperature (such as 80-85°C). It uses a compound withering method to initially process white tea. After withering the white tea for 12 hours (activating the activity of endogenous enzymes in the tea leaves) in an indoor environment at a room temperature of 25°C and an air humidity of 50%-60%, a sun-drying withering method for 3-4 hours is used for temperature increase treatment, and then withering indoors for another 10 hours. The enzymatic reaction is regulated in stages to promote the accumulation of precursor substances of floral and fruity aromas. Then the moisture content is reduced to 9%, enhancing the sweet aroma and freshness. It is piled up and packed in boxes, and after 7 days, the first firing is carried out, and finally, the second firing is carried out after 1 month. The whole low-temperature process makes the amino acid loss rate ≤7%, the fresh sweetness of the tea soup is increased by 20%, and the content of floral and fruity aroma substances (linalool, geraniol) is increased by 30%, making the aroma more plump when brewed at low temperature; the mellow taste is still maintained when brewed at low temperature. By optimizing the compound withering, drying, and firing processes, the present invention achieves a retention rate of white tea amino acids ≥93% and an increase in the content of aroma substances by 30%, suitable for low-temperature brewing.

[0034] As Figure 1 shown, the processing method for high-aroma and high-amino-acid white tea brewed at low temperature specifically includes the following steps:

[0035] S1. Picking: Select excellent Yunnan tea trees with good growth environments, appropriate picking times, and plump buds and leaves. Pick one-bud-one-leaf and one-bud-two-leaf fresh leaves as raw materials. Put the freshly picked tea leaves in a shady place and collect them in a breathable bamboo basket or bamboo crate. The freshly picked tea leaves need to be transferred to a shady place within 30 minutes (to avoid direct sunlight or heat accumulation due to piling up), stored separately in baskets according to one-bud-one-leaf and one-bud-two-leaf, and damaged, insect-bitten, or old leaves are removed to ensure the uniformity of the raw materials. The thickness of the fresh leaves spread in the bamboo basket does not exceed 5 cm, and they are gently turned over every 30 minutes to ensure uniform ventilation. Select a shallow-mouthed bamboo basket with a diameter ≤50 cm woven with thin bamboo strips and a porosity of 30%-40% to improve air permeability. Control the temperature of the collection environment at 20-25°C to avoid high temperatures accelerating the oxidation of fresh leaves or low temperatures causing inactivation (if the environmental temperature is higher than 25°C, a sunshade net or ventilation equipment can be added in the shady place, and a double-layer bamboo basket (the inner layer is breathable and the outer layer is heat-insulating) is used to buffer the external temperature change), and keep the relative air humidity at 65%-75% to prevent the fresh leaves from losing water too quickly or getting damp and stuffy. Use a temperature and humidity monitor to regulate in real time. If the humidity is too low, sprinkle water on the ground to increase humidity; if the humidity is too high, strengthen ventilation. The total time from picking the fresh leaves to entering the withering process does not exceed 2 hours to retain amino acids and aromatic substances to the greatest extent.

[0036] By controlling temperature and humidity and quickly collecting the green leaves, the activity of oxidase is reduced, and the amino acid loss rate can be reduced to less than 5%. The uniform spreading and sorting and grading of the fresh leaves promote the full release of volatile aroma components (such as linalool, geraniol) during the subsequent withering process. The fresh leaves after this step of treatment have high activity and rich internal substances. The finished white tea can quickly release the taste at low water temperatures, and the tea soup is fresh, sweet, and full.

[0037] S2. Compound withering: After withering the harvested tea leaves for 10 - 15 hours in an indoor environment with a room temperature of 20 - 25°C and an air humidity of 50% - 60%, a temperature increase treatment is carried out by the method of sun withering for 3 - 4 hours under sunny weather with a temperature of 25 - 30°C, and then withering indoors again for 8 - 12 hours. When sun withering, the thickness of the fresh leaves spread out should be ≤2 cm, and they are gently turned over once an hour. Choose to carry out sun withering from 9:00 - 11:00 in the morning or 15:00 - 17:00 in the afternoon to avoid the high temperature period at noon. During the first indoor withering, intermittent ventilation is combined, and the air is exchanged for 5 minutes every hour to promote the slow water loss of the fresh leaves; during the second indoor withering, the temperature is reduced to 18 - 22°C and the humidity is increased to 65% - 70% to delay the oxidation process and retain more amino acids and aromatic substances.

[0038] Synergistic effect:

[0039] Alternation of sun withering and indoor withering: Through the cycle of "short - time temperature increase (sun withering) + low - temperature slow withering (indoor)", the activity of polyphenol oxidase is activated, promoting the hydrolysis of aroma precursor substances (such as β - glucoside) and releasing floral and fruity aromas.

[0040] Enzymatic reaction balance: The temperature increase during the sun withering stage can accelerate the hydrolysis reaction in the initial stage of withering, while the low - temperature environment indoors in the second stage inhibits excessive oxidation and maintains the freshness of the tea soup.

[0041] Dynamic temperature and humidity control reduces the amino acid loss rate to less than 10% (the loss rate of the traditional process is about 15% - 20%). The contents of linalool and geraniol in the finished tea are increased by 20% - 30%, making the aroma more plump when brewing at low temperature.

[0042] S3. Drying: Drying is carried out by the method of low - temperature slow baking until the moisture content drops to 9%. Control the temperature for drying in stages; in the initial baking stage, the stepped temperature increase method is adopted, and the initial temperature is set at 80 - 85°C to avoid the decomposition of amino acids caused by high temperature. It lasts for 30 - 40 minutes to initially evaporate the moisture to about 15%. During the process, the tea leaves are evenly spread on a bamboo baking tray with a thickness of ≤2 cm and turned over every 15 minutes to ensure uniform heating; in the re - baking stage, the temperature is reduced to 60 - 65°C, and the humidity of the drying environment is maintained at ≤30% (to accelerate the diffusion of moisture and avoid the tea leaves from getting damp again), and the drying time is extended to 4 - 6 hours to slowly remove the remaining moisture to 9%, promoting the Maillard reaction between sugars and amino acids and enhancing the sweet aroma and freshness. During the drying process, the tea leaves can be cooled for 15 minutes after each hour of baking to redistribute the moisture inside and outside the tea leaves, avoiding the surface from being dry and hard and the inside from having uneven moisture content.

[0043] Through low - temperature slow baking, the amino acid loss rate can be controlled below 8%, and the freshness of the tea soup is improved. The stepped temperature increase promotes the degradation of lipid substances into floral aroma components (such as geraniol), and at the same time inhibits the volatilization of the grassy smell caused by high temperature. The finished tea has a significant high - aroma characteristic. The tea can quickly release its taste when brewed with water at 80 - 85°C.

[0044] S4. Roasting: The dried tea leaves are subjected to primary roasting after 7 days and then secondary roasting after 1 month. The initial roasting temperature is controlled within 70 °C, and the roasting time is 3 - 4 hours to activate the enzyme activity in the tea leaves and initially enhance the aroma, avoiding the destruction of amino acids by high temperatures; the secondary roasting temperature is lower than 70 °C, and the roasting time is 4 - 5 hours to promote the synergistic conversion of sugars and amino acids and strengthen the sweet aroma and freshness; and after the secondary roasting, aroma enhancement is carried out at a temperature between 30 - 50 °C for 1 hour. More preferably, the initial roasting temperature is controlled at 60 - 65 °C, and the tea leaves are turned over every 30 minutes (such as gently turning the tea leaves using the "sifting and inverting method" to ensure uniform heating and intact buds and leaves). After the initial roasting, the tea leaves are cooled for 24 hours to rebalance the internal and external moisture of the tea leaves, and then enter the secondary roasting to reduce the aroma dissipation caused by internal stress. Then enter the secondary roasting, and the secondary roasting temperature is reduced to 50 - 55 °C, and the environmental humidity is maintained at ≤40%. The roasting can use deep mountain fruit tree charcoal (such as longan wood, litchi wood), which has high combustion stability and contains natural aromatic substances, and can enhance the honey flavor of the tea.

[0045] Low-temperature segmented roasting reduces the loss rate of amino acids and significantly improves the fresh sweetness of the tea soup. Fruit tree charcoal roasting promotes the conversion of lipid substances into floral and fruity aromas (such as phenethyl alcohol, linalool), while retaining the tip aroma. The aroma precipitation rate of the finished tea during cold brewing is increased, and the tea soup is mellow.

[0046] S5. Packing to complete the preparation of white tea.

[0047] Example 1

[0048] A processing method for low-temperature brewing high-aroma and high-amino-acid white tea, which comprises the following steps:

[0049] S1. Picking: Select excellent Yunnan tea trees with good growth environments, appropriate picking times, and plump buds and leaves. Picking one-bud-one-leaf and one-bud-two-leaf fresh leaves as raw materials, putting the freshly picked tea leaves in a shady place, and collecting the green leaves with breathable bamboo baskets or wicker baskets; the freshly picked tea leaves need to be transferred to a shady place within 30 minutes, stored separately in baskets according to one-bud-one-leaf and one-bud-two-leaf, the thickness of the fresh leaves spread in the bamboo basket is 3 cm, and gently turned over every 30 minutes. Select a shallow-mouthed bamboo basket with a diameter ≤50 cm woven with thin bamboo strips and a porosity of 35%. The temperature of the green leaf collection environment is controlled at 20 °C, the relative air humidity is maintained at 65%, and the total time from picking to entering the withering process of the fresh leaves is controlled within 1.5 hours.

[0050] S2. Compound withering: After withering the freshly harvested tea leaves for 10 hours in an indoor environment with a room temperature of 20°C and an air humidity of 50%, a temperature increase treatment is carried out by the method of sun withering for 3 hours under sunny weather with a temperature of 25°C, and then withering indoors for another 8 hours. When withering, the thickness of the fresh leaves spread out is 2 cm, and they are gently turned over once an hour. Sun withering is carried out at 9:00 - 11:00 in the morning or 15:00 - 17:00 in the afternoon. During the first indoor withering, intermittent ventilation is combined, and the air is exchanged for 5 minutes every hour; during the second indoor withering, the temperature is reduced to 18°C and the humidity is increased to 65%.

[0051] S3. Drying: Low-temperature slow baking is adopted for staged temperature-controlled drying; in the initial baking stage, the stepped temperature increase method is used, the initial temperature is set at 80°C, and it lasts for 30 minutes to initially evaporate the moisture to about 15%. During the process, the tea leaves are evenly spread on a bamboo baking tray with a thickness of 2 cm and turned over every 15 minutes; in the re-baking stage, the temperature is reduced to 60°C, the humidity of the drying environment is kept ≤30%, and the drying time is extended to 4 hours to slowly remove the remaining moisture to 9%.

[0052] S4. Roasting: The tea leaves after drying treatment are initially roasted 7 days later and finally roasted again 1 month later; the initial roasting temperature is controlled at 60°C and the roasting time is 3 hours; the re-roasting temperature is reduced to 50°C and the roasting time is 5 hours; and after re-roasting, flavor enhancement is carried out at a temperature of 50°C and a roasting time of 1 hour. During the initial roasting, it is turned over every 30 minutes. After the initial roasting, it is cooled and then enters the re-roasting. The humidity of the re-roasting environment is kept ≤40%.

[0053] S5. Packing to complete the preparation of white tea.

[0054] Example 2

[0055] The difference between this example and Example 1 is only that: in S1, the temperature of the green-harvesting environment is controlled at 25°C and the relative air humidity is kept at 75%. In S2, after withering the freshly harvested tea leaves for 15 hours in an indoor environment with a room temperature of 25°C and an air humidity of 60%, a temperature increase treatment is carried out by the method of sun withering for 3 hours under sunny weather with a temperature of 30°C, and then withering indoors for another 12 hours. During the second indoor withering, the temperature is reduced to 22°C and the humidity is increased to 70%. In S3, in the initial baking stage, the initial temperature is set at 85°C and it lasts for 40 minutes. In the re-baking stage, the temperature is reduced to 65°C and the drying time is extended to 4 hours. In S4, the initial roasting temperature is controlled at 65°C and the roasting time is 4 hours; the re-roasting temperature is reduced to 55°C and the roasting time is 5 hours; and after re-roasting, flavor enhancement is carried out at a temperature of 30°C and a roasting time of 1 hour.

[0056] Example 3

[0057] The differences between this embodiment and Embodiment 1 are only as follows: In S1, the temperature of the green tea collection environment is controlled at 23°C, and the relative air humidity is maintained at 70%. In S2, after the harvested tea leaves are withered for 12 hours in an indoor environment at a room temperature of 23°C and an air humidity of 60%, a temperature increase treatment is carried out by the method of sun withering for 3.5 hours under sunny weather with a temperature of 28°C, and then withered indoors again for 10 hours. During the second indoor withering, the temperature is still 23°C and the humidity is increased to 68%. In S3, in the initial baking stage, the initial temperature is set at 82°C for 35 minutes. In the re-baking stage, the temperature is lowered to 62°C and the drying time is extended to 5 hours. In S4, the initial roasting temperature is controlled at 62°C and the roasting time is 3.5 hours; the re-roasting temperature is lowered to 52°C and the roasting time is 4.5 hours; and after re-roasting, flavor enhancement is carried out at a temperature of 40°C for 1 hour.

[0058] The specific embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the scope of knowledge possessed by those of ordinary skill in the art.

Claims

1. A method for processing low-temperature brewing high-fragrance and high-amino acid white tea, characterized in that: The white tea is initially processed by a double withering method. After withering for 12 hours at a room temperature of 25°C and an air humidity of 50%-60% indoors, the white tea is subjected to a temperature-raising treatment by sun withering for 3-4 hours. The tea is then withered again indoors for 10 hours until the moisture content drops to 9%. The tea is then piled and boxed, and roasted for the first time after 7 days. The tea is then roasted again after 1 month.

2. The method for processing low-temperature brewing high-fragrance high-amino acid white tea according to claim 1, characterized in that: The following steps are involved: S1. Picking: Select excellent Yunnan tea trees with good growth environment, suitable picking time and strong buds and leaves, pick fresh leaves with one bud and one leaf or one bud and two leaves as raw materials, put the freshly picked tea leaves in a cool place, and collect them in breathable bamboo baskets or baskets; S2. Compound withering: wither the harvested tea leaves for 10-15 hours at a room temperature of 20-25°C and an air humidity of 50%-60% in an indoor environment, then heat them up by withering them in the sun at a temperature of 25°C-30°C for 3-4 hours, and then wither them again in the room for 8-12 hours; S3, Drying: Drying is carried out by slow baking at low temperature, and the moisture content is reduced to 9%; S4, roasting: roasting the dried tea leaves for the first time after 7 days, and roasting them again after 1 month; S5, packing, completing the white tea preparation.

3. The method for processing low-temperature brewing high-fragrance high-amino acid white tea according to claim 2, characterized in that: In step S1, the fresh leaves need to be transferred to a cool place within 30 minutes after being picked, and stored in baskets according to one bud and one leaf or one bud and two leaves. The thickness of the fresh leaves in the bamboo baskets should not exceed 5 cm, and they should be gently turned over every 30 minutes. Shallow bamboo baskets with a diameter of ≤50 cm woven with thin bamboo strips and a porosity of 30%-40% should be selected.

4. The method for processing low-temperature brewing high-fragrance high-amino acid white tea according to claim 3, characterized in that: In step S1, the temperature of the harvesting environment is controlled at 20-25°C, the relative humidity of the air is maintained at 65%-75%, and the total time from picking the fresh leaves to entering the withering process does not exceed 2 hours.

5. The method for processing low-temperature brewing high-fragrance high-amino acid white tea according to claim 4, characterized in that: In step S2, the harvested tea leaves are withered for 12 hours in an indoor environment at a room temperature of 20-25°C and an air humidity of 50%-60%, and then heated by withering in the sun at a temperature of 25°C to 30°C for 3-4 hours, and then withered again indoors for 10 hours.

6. The method for processing low-temperature brewing high-fragrance high-amino acid white tea according to claim 5, characterized in that: When withering, spread the fresh leaves to a thickness of ≤2 cm and turn them over gently every hour. Choose 9:00-11:00 in the morning or 15:00-17:00 in the afternoon for sun exposure.

7. The method for processing low-temperature brewing high-fragrance high-amino acid white tea according to claim 6, characterized in that: During the first indoor withering, intermittent ventilation is combined, with 5 minutes of air change per hour; during the second indoor withering, the temperature is reduced to 18-22℃ and the humidity is increased to 65%-70%.

8. The method for processing low-temperature brewing high-fragrance high-amino acid white tea according to claim 7, characterized in that: In step S3, the drying is carried out in stages with controlled temperature. In the initial drying stage, a step-by-step heating method is adopted, and the initial temperature is set to 80-85°C for 30-40 minutes to evaporate the moisture to 15%. During the process, the tea leaves are evenly spread on a bamboo drying tray with a thickness of ≤2 cm and are turned over every 15 minutes. In the secondary drying stage, the temperature is lowered to 60-65°C, the humidity of the drying environment is maintained at ≤30%, the drying time is extended to 4-6 hours, and the remaining moisture is slowly removed to 9%.

9. The method for processing low-temperature brewing high-fragrance high-amino acid white tea according to claim 8, characterized in that: In the step S4, the primary baking temperature is controlled within 70°C, and the baking time is 3-4 hours; the secondary baking temperature is lower than 70°C, and the baking time is 4-5 hours; and after the secondary baking, the aroma is enhanced, the temperature is between 30-50 degrees, and the baking time is 1 hour.

10. The method for processing low-temperature brewing high-fragrance high-amino acid white tea according to claim 9, characterized in that: The primary baking temperature is controlled at 60-65° C., and the food is turned over every 30 minutes. After the primary baking, the food is spread out to cool, and then the secondary baking is started. The secondary baking temperature is cooled to 50-55° C., and the environmental humidity is maintained at ≤40%.

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