A method for directional and precise processing of a tender and fragrant curly green tea

Abstract

The application discloses a kind of tender aroma type curling shape green tea directional precision processing method, belongs to tea processing technical field.The method with tender aroma flavor directional generation as core, in turn through raw material aroma grading screening, precision spreading, high-temperature rapid fixation, three-stage variable-temperature striping supplementary fixation, variable-pressure variable-speed combination rolling, fast initial baking setting, enough fire plastic fragrance solidification seven processes, through whole-process parameter precision matching and process cooperation, directional promote aroma precursor to tender aroma direction conversion and stable solidification.The application can realize the standardized stable production of tender aroma type curling shape green tea, the finished product tender aroma is rich and lasting, taste is fresh and mellow, effectively solve the problem that existing process tender aroma characteristic randomness is strong, quality fluctuation is big.

Description

Technical Field

[0001] This invention relates to the field of tea processing technology, specifically a method for the precise and directional processing of tender, fragrant, curled green tea. Background Technology

[0002] Green tea is the tea category with the highest production volume and the widest consumer base in my country. Aroma is one of the core indicators for judging the quality grade of green tea, directly determining its commercial value and market competitiveness. A delicate aroma is the hallmark of high-grade green tea, characterized by its elegant, fresh, and slightly sweet fragrance. This aroma primarily originates from aromatic precursors in fresh leaves that undergo appropriate thermal conversion, requiring extremely high precision in parameter control during processing.

[0003] Currently, green tea processing largely follows a generic process, typically selecting raw materials solely based on tenderness without grading or selectively screening the aroma qualities of the fresh leaves. This results in a mixture of leaves with different aroma potentials, leading to a blurred aroma profile in the finished product and an inability to consistently highlight the delicate fragrance. In the heat processing stage, conventional fixation parameters are often set too broadly, failing to optimize for the targeted transformation of aroma precursors. This can easily lead to incomplete enzyme deactivation resulting in a grassy aroma, or excessively high temperatures and prolonged processing causing a burnt flavor that masks the delicate fragrance, making it difficult to achieve a balance between thorough fixation and aroma preservation.

[0004] The rolling process generally employs a constant pressure and speed processing mode, making it impossible to precisely control the degree of cell damage. Over-rolling easily leads to premature oxidation and loss of aroma substances, while under-rolling results in insufficient release of flavor substances and difficulty in forming a uniform curled shape. The drying process often uses one-time drying or simple staged drying, lacking the design of temperature, humidity, and air speed parameters specifically for the formation and fixation of delicate aroma substances. This makes it impossible to consolidate and modify the already formed aroma substances, resulting in poor aroma persistence in the finished tea, and the delicate aroma is easily lost during storage.

[0005] Overall, existing green tea processing technology lacks a targeted control system with tender aroma as the core objective. There is a lack of coordination and matching between parameters of each process. The formation of tender aroma is highly dependent on the endowment of raw materials and the experience of processing personnel. The quality fluctuates greatly between batches, making it difficult to achieve large-scale and standardized production of tender aroma green tea and failing to meet the demand of the high-end green tea market for stable quality. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a directional and precise processing method for tender-aroma curled green tea. With the stable generation of tender aroma as the core, a complete tender aroma control chain is constructed through directional screening of aroma at the raw material end, precise setting of parameters throughout the processing process, and coordinated operation of processes. This solves the problems of strong randomness of tender aroma characteristics, large quality fluctuations, and easy interference from grassy or high-fired flavors in the existing process, and realizes the standardized production of tender-aroma green tea.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0008] A method for targeted and precise processing of tender, fragrant, curled green tea includes the following steps:

[0009] S1. Raw material aroma grading and screening: Fresh leaves are graded by aroma sensory evaluation, and fresh leaves with medium floral fragrance are selected as processing raw materials. The tenderness of the raw materials is one bud and two leaves that are just unfolded or above.

[0010] S2. Precise spreading: Spread the selected fresh leaves evenly, controlling the moisture content at the end of spreading to 68%–70%;

[0011] S3. High-temperature rapid blanching: The spread-out fresh leaves are sent into a drum blanching machine for blanching treatment, which deactivates the endogenous enzyme activity of the fresh leaves.

[0012] S4. Three-stage variable temperature shaping and finishing: The withered leaves are put into a three-stage flat tea frying machine, and the leaves are shaped and finished by three stages of gradient cooling. After processing, the moisture content of the tea leaves is controlled at 58% to 60%.

[0013] S5. Variable pressure and variable speed combined kneading: The tea leaves after shaping and finishing are fed into the variable frequency kneading machine and kneaded in sections according to the order of light pressure, medium pressure, heavy pressure and loose pressure, with corresponding speeds to shape curled strips.

[0014] S6. Rapid initial drying and shaping: The rolled leaves are sent into a chain dryer for initial drying until the tea leaves are 70-80% dry, thus fixing the shape of the strips.

[0015] S7. Full-heat roasting to enhance aroma and solidify fragrance: Place the initially dried leaves in a box-type roasting and aroma-enhancing machine for full-heat roasting until the tea leaves are fully dry, thus producing tender-aroma curled green tea.

[0016] Furthermore, in step S1, the floral fragrance grade is based on the fragrance intensity of the linalool standard solution, and the medium floral fragrance corresponds to a fragrance concentration of 20-25 μg / L of linalool solution.

[0017] Fresh leaves are classified into three grades: high, medium, and low, based on their floral fragrance. Only leaves with a medium floral fragrance grade are selected for processing, while raw materials with excessively high or low floral fragrance are discarded.

[0018] Furthermore, in step S2, the thickness of the fresh leaves spread out is 3-7 cm, and the spreading time is 6-15 h;

[0019] The ambient temperature for spreading should be controlled at 20-25℃, and the relative humidity at 65%-75%. The fresh leaves should be turned over lightly every 2 hours during the spreading process to ensure even water loss.

[0020] Furthermore, in step S3, the temperature of the drum wall of the drum blanching machine is controlled at 390-430℃, and the blanching time is 2.5-3 minutes;

[0021] After the fixation process, the tea leaves are soft, can be clumped together when squeezed in the hand and crumble when released, the grassy smell has basically dissipated and a fresh fragrance has emerged, and the moisture content of the fixation leaves is 62% to 65%.

[0022] Furthermore, in step S4, the temperature of the first stage of the three-stage variable temperature strip treatment is 190-200℃, the temperature of the second stage is 150-160℃, and the temperature of the third stage is 130-140℃.

[0023] The total processing time for the three stages is 3 to 3.5 minutes, and the amount of tea leaves added at one time is 300 to 350g. The reciprocating vibration of the frying machine trough drives the tea leaves into strips, while simultaneously dissipating the remaining grassy smell and completely deactivating the enzymes.

[0024] Furthermore, in step S5, the specific procedure for the variable pressure and variable speed combined kneading is as follows:

[0025] First, knead lightly at 40-45 rpm for 10 minutes, then knead at 55-60 rpm for 8 minutes, then knead heavily at 40-45 rpm for 5 minutes, and finally knead loosely at 55-60 rpm for 2 minutes.

[0026] During the rolling process, the rolling drum is fully loaded. After rolling, the cell damage rate of the tea leaves is controlled to be 45% to 55%, and the tea leaves are tightly rolled into a spiral shape.

[0027] Furthermore, in step S6, the air inlet temperature of the chain dryer is controlled at 150-160℃, and the initial drying time is 2.5-3 minutes. After the initial drying, the tea leaves are shaped and can be touched by hand. The moisture content of the tea leaves is 20%-25%. After the initial drying, the leaves are promptly spread out to cool and rehydrate, so that the internal moisture of the tea leaves is redistributed evenly.

[0028] Furthermore, in step S7, the baking temperature of the box-type roasting and aroma-enhancing machine is 105-110℃, the air velocity inside the box is 5-5.5m / s, the tea leaves are spread to a thickness of 4-8cm, and the baking time is 30-35min.

[0029] The tea leaves are stirred every 10 minutes during the roasting process to ensure even heating. After roasting, the moisture content of the tea leaves is 4% to 6%, reaching a fully dry state.

[0030] Furthermore, after step S7 is completed, the tea leaves are cooled to room temperature, sorted to remove impurities, graded, and then sealed and packaged. The finished tea has a tightly rolled and curled appearance with visible white hairs, a green and lustrous color, a delicate and lasting aroma, a fresh, mellow, and refreshing taste, and tender, uniform green leaves.

[0031] This invention provides a method for the precise and targeted processing of tender, fragrant, curled green tea, which has the following beneficial effects:

[0032] Firstly, this invention breaks away from the traditional model of selecting raw materials solely based on tenderness, and introduces an aroma grading mechanism. Using linalool standard solution as a reference, it selects fresh leaves with medium floral fragrance in a targeted manner, homogenizing the aroma precursor material basis from the source. This avoids the problem of high floral fragrance fresh leaves deviating in aroma after processing and low floral fragrance fresh leaves lacking tender aroma, thus providing a stable raw material prerequisite for the targeted generation of tender aroma.

[0033] Subsequently, by precisely controlling the spreading thickness, ambient temperature and humidity, and final moisture content, the fresh leaves are allowed to lose water evenly and slowly. This promotes the appropriate transformation of aroma precursors in the fresh leaves while avoiding excessive water loss that could lead to residual grassy smell or loss of aroma substances due to excessive water loss, thus providing a suitable moisture reaction matrix for subsequent thermal processing.

[0034] Furthermore, a combined process of high-temperature rapid fixation and three-stage variable-temperature shaping and supplementary fixation is employed. High-temperature rapid fixation can thoroughly deactivate endogenous enzyme activity in a short time, reducing the enzymatic oxidation loss of aroma precursors; the subsequent three-stage gradient cooling shaping process promotes the directional thermal conversion of aroma precursors towards a tender aroma through tiered thermal action, while gradually dissipating residual grassy aroma. This avoids the high-burning flavor caused by continuous high temperatures and solves the problem of insufficient fixation and heavy grassy aroma caused by single fixation processes, achieving a balance between thorough fixation and aroma preservation.

[0035] Simultaneously, it pioneered a variable pressure and speed combination program that progresses sequentially from light pressure to medium pressure, heavy pressure, and loose pressure. Through coordinated adjustment of pressure and speed, it precisely controls the cell damage rate of tea leaves within an appropriate range. The light pressure stage initially kneads the leaves into strips, the medium pressure stage gradually releases flavor substances, the heavy pressure stage strengthens the tightness of the strips, and the loose pressure stage breaks up clumps and organizes the strips. Throughout the process, it ensures the appropriate release of flavor substances while avoiding excessive cell damage that could lead to premature oxidation and loss of aroma substances, thus achieving a harmonious balance between appearance, flavor, and aroma.

[0036] In the drying process, the shape of the strips is first fixed by rapid initial drying to reduce the loss of aroma in subsequent processes. Then, the precise temperature field and wind speed settings of the box-type baking aroma-enhancing machine are used to shape and fix the tender aroma substances during the full drying process, promote the balanced transformation of aroma substances, improve the purity and persistence of the tender aroma, and avoid the problems of rapid aroma loss and lack of style in conventional drying processes.

[0037] Precise parameter matching and coordinated processes between each step form a complete chain for targeted control of tender aroma. The processing does not rely on human experience and judgment, enabling standardized and large-scale production. The finished tea has stable tender aroma characteristics and high batch-to-batch quality consistency, effectively enhancing the product grade and market value of green tea. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the process flow of the invention. Detailed Implementation

[0039] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0040] Example 1

[0041] The method for precise processing of tender, fragrant, curled green tea according to this embodiment includes the following steps:

[0042] S1. Pick fresh tea leaves with one bud and two newly unfolded leaves. Professional evaluators will conduct aroma sensory evaluation. Using 22μgL linalool standard solution as a reference, select fresh leaves with moderate floral fragrance as raw materials and remove fresh leaves with excessive or insufficient floral fragrance.

[0043] S2. Spread the selected fresh leaves evenly on the bamboo drying rack with a thickness of 3cm. Control the ambient temperature at 22℃ and the relative humidity at 70%. Turn the fresh leaves lightly every 2 hours. After 6 hours of spreading, the moisture content of the fresh leaves is 68%, which is the end point of spreading.

[0044] S3. Send the spread-out fresh leaves into a 60-type drum blanching machine, control the drum wall temperature to 390℃, and blanching time to 3 minutes.

[0045] After the fixation process, the tea leaves are soft, can be clumped together when squeezed but crumbles easily when released, the grassy smell has mostly dissipated and a fresh fragrance has emerged, and the moisture content of the fixation leaves is 64%;

[0046] S4. The withered leaves are fed into a three-stage flat tea frying machine and subjected to a three-stage gradient cooling process: the first stage is at 200℃, the second stage at 150℃, and the third stage at 130℃. The total processing time is 3 minutes, and the amount of leaves fed at one time is 350g. After processing, the tea leaves are initially formed into strips, and the moisture content is measured to be 58%.

[0047] S5. Load the tea leaves, after shaping and finishing, into the variable frequency rolling machine and roll them according to the program:

[0048] First, gently knead the tea leaves at 45 rpm for 10 minutes, then knead at 60 rpm for 8 minutes, followed by kneading at 45 rpm for 5 minutes, and finally kneading at 60 rpm for 2 minutes. After kneading, the tea leaves are tightly rolled, and the cell damage rate is 48%.

[0049] S6. Spread the kneaded leaves evenly on the chain dryer, control the air inlet temperature to 150℃, and dry for 3 minutes initially. Dry until the tea leaves are 70-80% dry, feel soft to the touch, and test the moisture content to be 23%. After the initial drying, spread them out to cool and rehydrate for 15 minutes.

[0050] S7. Transfer the initially dried leaves into a box-type roasting and aroma-enhancing machine. Set the temperature to 110℃, the air speed inside the box to 5m / s, the tea leaves to be spread to a thickness of 4cm, and the roasting time to 30min. Stir the tea leaves every 10min during the roasting process.

[0051] The tea leaves are roasted until fully dry, and the moisture content is measured to be 5.2%. After cooling to room temperature, impurities are removed to obtain the finished tea.

[0052] Example 2

[0053] The method for precise processing of tender, fragrant, curled green tea according to this embodiment includes the following steps:

[0054] S1. Pick fresh tea leaves with one bud and one leaf, and conduct aroma sensory evaluation by professional evaluators. Using 25μgL linalool standard solution as a reference, select fresh leaves with medium floral fragrance as raw materials and remove fresh leaves with excessive or insufficient floral fragrance.

[0055] S2. Spread the selected fresh leaves evenly on the bamboo drying rack with a thickness of 7cm. Control the ambient temperature at 20℃ and the relative humidity at 75%. Turn the fresh leaves lightly every 2 hours. After 15 hours of spreading, the moisture content of the fresh leaves is tested and found to be 70%, which is the end point of spreading.

[0056] S3. After spreading out the fresh leaves, feed them into a 60-type drum fixing machine, control the drum wall temperature at 430℃, and fix for 2.5 minutes. After fixing, the tea leaves are soft, can be clumped together when squeezed, and crumble when released. The grassy smell has basically dissipated, and a fresh aroma is revealed. The moisture content of the fixed leaves is 63%.

[0057] S4. The withered leaves are fed into a three-stage flat tea frying machine and subjected to a three-stage gradient cooling process: the first stage temperature is 190℃, the second stage temperature is 160℃, and the third stage temperature is 140℃. The total processing time is 3.5 minutes, and the amount of leaves fed at one time is 300g. After processing, the tea leaves are initially shaped into strips, and the moisture content is tested to be 60%.

[0058] S5. Load the tea leaves, after shaping and finishing, into a variable frequency rolling machine and roll them according to the program: first, lightly roll at 40 rpm for 10 minutes, then roll at 55 rpm for 8 minutes, followed by heavy rolling at 40 rpm for 5 minutes, and finally loosely roll at 55 rpm for 2 minutes; after rolling, the tea leaves are tightly rolled, and the cell damage rate is 52%;

[0059] S6. Spread the kneaded leaves evenly on the chain dryer, control the air inlet temperature to 160℃, and dry for 2.5 minutes. Dry until the tea leaves are 70-80% dry, feel soft to the touch, and the moisture content is 22%. After the initial drying, let them cool and rehydrate for 15 minutes.

[0060] S7. Transfer the initially dried leaves into a box-type roasting and aroma-enhancing machine, set the temperature to 110℃, the air speed inside the box to 5.5m / s, the tea leaves to a thickness of 8cm, and roast for 35 minutes. Stir the tea leaves every 10 minutes during the roasting process. Roast until the tea leaves are completely dry, and the moisture content is measured to be 4.8%. After cooling to room temperature, pick out any impurities to obtain the finished tea.

[0061] Example 3

[0062] The method for precise processing of tender, fragrant, curled green tea according to this embodiment includes the following steps:

[0063] S1. Pick fresh tea leaves with one bud and one leaf just unfolding. Professional evaluators will conduct aroma sensory evaluation. Using 20μgL linalool standard solution as a reference, select fresh leaves with medium floral fragrance as processing raw materials and remove fresh leaves with excessive or insufficient floral fragrance.

[0064] S2. Spread the selected fresh leaves evenly on the bamboo drying rack with a thickness of 5cm. Control the ambient temperature at 25℃ and the relative humidity at 65%. Turn the fresh leaves lightly every 2 hours. After 10 hours of spreading, the moisture content of the fresh leaves is tested and found to be 70%, which is the end point of spreading.

[0065] S3. After spreading out the fresh leaves, feed them into a 60-type drum fixation machine, control the drum wall temperature at 405℃, and fix for 3 minutes. After fixation, the tea leaves are soft, can be clumped together when squeezed, and crumble when released. The grassy smell has basically dissipated, and a fresh aroma is revealed. The moisture content of the fixation leaves is 62%.

[0066] S4. Put the blanched leaves into a three-stage flat tea frying machine and process them in three stages of gradient cooling. The first stage temperature is 195℃, the second stage temperature is 155℃, and the third stage temperature is 135℃. The total processing time is 3 minutes, and the amount of leaves added at one time is 320g.

[0067] After processing, the tea leaves were initially shaped into strips, and the moisture content was found to be 59%.

[0068] S5. Load the tea leaves, after shaping and finishing, into the variable frequency rolling machine and roll them according to the program:

[0069] First, gently knead the tea leaves at 45 rpm for 10 minutes, then knead at 55 rpm for 8 minutes, followed by kneading at 40 rpm for 5 minutes, and finally kneading at 60 rpm for 2 minutes. After kneading, the tea leaves are tightly rolled, and the cell damage rate is 50%.

[0070] S6. Spread the kneaded leaves evenly on the chain dryer, control the air inlet temperature to 155℃, and dry for 3 minutes initially. Dry until the tea leaves are 70-80% dry, feel soft to the touch, and the moisture content is 24%. After the initial drying, spread them out to cool and rehydrate for 15 minutes.

[0071] S7. Transfer the initially dried leaves into a box-type roasting and aroma-enhancing machine. Set the temperature to 105℃, the air speed inside the box to 5.3m / s, the tea leaves to a thickness of 6cm, and the roasting time to 35min. Stir the leaves every 10min during the roasting process.

[0072] The tea leaves are roasted until fully dry, and the moisture content is measured to be 5.0%. After cooling to room temperature, impurities are removed to obtain the finished tea.

[0073] Comparative Example 1

[0074] The only difference between this comparative example and Example 3 is that step S7 does not use a box-type roasting and aroma-enhancing machine, but instead uses a conventional bucket dryer for full-heat drying at a temperature of 95°C until the tea leaves have a moisture content of 5.0%. The remaining process parameters are completely consistent with those of Example 3.

[0075] Comparative Example 2

[0076] The only difference between this comparative example and Example 3 is that in step S1, the aroma grading and screening of raw materials is not performed, and mixed fresh leaves of the same tenderness (randomly mixed fresh leaves with high, medium and low floral aroma) are directly used as raw materials. The remaining process parameters are completely consistent with those of Example 3.

[0077] Comparative Example 3

[0078] The only difference between this comparative example and Example 3 is that step S5 does not use variable pressure and variable speed combined kneading, but instead uses conventional constant pressure and constant speed kneading, that is, 50 rpm rotation speed and constant medium pressure kneading for 25 minutes. After kneading, the cell damage rate was found to be 62%. The remaining process parameters are completely consistent with those of Example 3.

[0079] Sample testing and sensory evaluation results

[0080] All samples were subjected to sensory evaluation by multiple tea evaluators according to the green tea evaluation standards, using a 100-point scoring system. Simultaneously, gas chromatography was used to detect the content of the main aroma components in the samples. The detection and evaluation results are shown in the table below:

[0081] Table 1 Sensory evaluation scores for each sample

[0082] Table 2 Comparison of key physicochemical parameters of each sample

[0083] The results above show that the total sensory evaluation scores of the three sample examples are significantly higher than those of the comparative examples, with a particularly obvious advantage in aroma scores. The contents of aroma components related to tender aroma, such as linalool and geraniol, are higher, while the contents of hexenal, which represents grassy aroma, are lower. This indicates that the method of the present invention can effectively promote the formation of tender aroma substances, reduce grassy aroma residue, and achieve targeted regulation of tender aroma flavor.

[0084] Comparative Example 1, due to the lack of precise aroma shaping process in the final firing stage, had obvious residual grassy aroma in the finished product, and the tender aroma could not be fully highlighted, indicating that the final firing stage for aroma shaping and fixation is the key process for the final formation and stabilization of tender aroma; Comparative Example 2, due to the lack of raw material aroma grading, had a low content of aroma components in the finished product and the tender aroma characteristics were not prominent, indicating that the targeted selection of aroma at the raw material end is a basic prerequisite for the formation of tender aroma; Comparative Example 3, using conventional constant pressure kneading, had an excessively high cell damage rate, increased loss of aroma substances, and a decline in tender aroma performance, indicating that variable pressure and variable speed kneading plays an important role in aroma preservation.

[0085] It is worth noting that the aroma sensory evaluation step conducted by professional evaluators can be replaced by other professional methods in actual production applications, such as electronic nose detection or screening by professional component instruments. However, the applicant has found in his many years of tea research that the comprehensiveness and intuitiveness of sensory evaluation are more suitable than instruments.

[0086] In summary, this invention, through precise and coordinated control of all processes, can stably produce tender, fragrant, and mellow curled green tea, effectively solving the problem of unstable tender aroma and quality in existing processes.

[0087] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for precise directional processing of tender, fragrant, curled green tea, characterized in that, Includes the following steps: S1. The aroma sensory grade of fresh leaves is carried out, and fresh leaves with medium floral fragrance are selected as raw materials for processing. The tenderness of the raw materials is one bud and two leaves that are just unfolded or above. S2. Spread the screened fresh leaves evenly, controlling the moisture content at the end of spreading to be 68%–70%; S3. After spreading out the fresh leaves, send them into a drum blanching machine for blanching treatment to deactivate the endogenous enzyme activity of the fresh leaves. S4. Put the withered leaves into a three-stage flat tea frying machine, and perform strip shaping and supplementary withering in three stages of gradient cooling. After processing, control the moisture content of the tea leaves to be 58% to 60%. S5. After the tea leaves have been processed and dried, they are fed into a variable frequency rolling machine and rolled in sections according to the order of light pressure, medium pressure, heavy pressure and loose pressure, with corresponding speeds, to shape the curled tea leaves. S6. Send the rolled leaves into the chain dryer for initial drying until the tea leaves are 70-80% dry, and fix the shape of the strips. S7. Place the initially dried leaves in a box-type roasting and aroma-enhancing machine for full-heat roasting until the tea leaves are fully dry, to obtain tender-aroma curled green tea.

2. The method for directional and precise processing of tender-aroma curled green tea according to claim 1, characterized in that, In step S1, the fragrance grade is based on the fragrance intensity of the linalool standard solution. The medium fragrance corresponds to a fragrance concentration of 20-25 μg / L of linalool solution. Fresh leaves are divided into three grades: high, medium, and low according to the degree of fragrance. Only fresh leaves with medium fragrance are selected for processing, and raw materials with excessively high or low fragrance are discarded.

3. The method for directional and precise processing of tender-aroma curled green tea according to claim 1, characterized in that, In step S2, the thickness of the fresh leaves is 3-7 cm, and the spreading time is 6-15 hours; The ambient temperature for spreading should be controlled at 20-25℃, and the relative humidity at 65%-75%. The fresh leaves should be turned over lightly every 2 hours during the spreading process to ensure even water loss.

4. The method for directional and precise processing of tender-aroma curled green tea according to claim 1, characterized in that, In step S3, the temperature of the drum wall of the drum blanching machine is controlled at 390-430℃, and the blanching time is 2.5-3 minutes. After the fixation process, the tea leaves are soft, can be clumped together when squeezed in the hand and crumble when released, the grassy smell has basically dissipated and a fresh fragrance has emerged, and the moisture content of the fixation leaves is 62% to 65%.

5. The method for directional and precise processing of tender-aroma curled green tea according to claim 1, characterized in that, In step S4, the temperature of the first stage of the three-stage variable temperature strip finishing process is 190-200℃, the temperature of the second stage is 150-160℃, and the temperature of the third stage is 130-140℃. The total processing time for the three stages is 3 to 3.5 minutes, and the amount of tea leaves added at one time is 300 to 350g. The reciprocating vibration of the frying machine trough drives the tea leaves into strips, while simultaneously dissipating the remaining grassy smell and completely deactivating the enzymes.

6. The method for directional and precise processing of tender-aroma curled green tea according to claim 1, characterized in that, In step S5, the specific procedure for the variable pressure and variable speed combined kneading is as follows: First, knead lightly at 40-45 rpm for 10 minutes, then knead at 55-60 rpm for 8 minutes, then knead heavily at 40-45 rpm for 5 minutes, and finally knead loosely at 55-60 rpm for 2 minutes. During the rolling process, the rolling drum is fully loaded. After rolling, the cell damage rate of the tea leaves is controlled to be 45% to 55%, and the tea leaves are tightly rolled into a spiral shape.

7. The method for directional and precise processing of tender-aroma curled green tea according to claim 1, characterized in that, In step S6, the air inlet temperature of the chain dryer is controlled at 150-160℃, and the initial drying time is 2.5-3 minutes. After the initial drying, the tea leaves are shaped and can be touched. The moisture content of the tea leaves is 20%-25%. After the initial drying, the leaves are promptly spread out to cool and rehydrate, so that the internal moisture of the tea leaves is redistributed evenly.

8. The method for directional and precise processing of tender-aroma curled green tea according to claim 1, characterized in that, In step S7, the roasting temperature of the box-type roasting and aroma-enhancing machine is 105-110℃, the air velocity inside the box is 5-5.5m / s, the tea leaves are spread out to a thickness of 4-8cm, and the roasting time is 30-35min. The tea leaves are stirred every 10 minutes during the roasting process to ensure even heating. After roasting, the moisture content of the tea leaves is 4% to 6%, reaching a fully dry state.

9. The method for directional and precise processing of tender-aroma curled green tea according to claim 1, characterized in that, After step S7 is completed, the tea leaves are spread out to cool to room temperature, then sorted, graded, and sealed in packaging. The finished tea has a tightly rolled and curled appearance with visible white hairs, a green and lustrous color, a delicate and lasting aroma, a fresh, mellow, and refreshing taste, and tender, uniform green leaves.

Images