A step-by-step temperature-adjusting manual frying method for Longjing golden bud tea leaves

Abstract

This invention discloses a step-temperature controlled manual processing method for Longjing Golden Bud tea, relating to the technical field, and includes the following steps: Step 1, Harvesting process: After the morning dew dries and before 9:30 AM, harvest fresh Golden Bud leaves that meet the standard of "one bud and one leaf just beginning to unfold" or "one bud and two leaves just beginning to unfold"; Step 2, Spreading process: Spread the harvested fresh leaves to a thickness of 2-3 cm for 2-3 hours until the moisture content drops to 70%-75%. This invention is highly targeted and fully adapted to the characteristics of the Golden Bud variety: This invention is specifically designed for the characteristics of Golden Bud, such as high amino acid content, low tea polyphenol content, thin leaves, and long bud nodes. Through the refined parameter setting of 250℃ high-temperature fixation for 15 minutes, it not only achieves sufficient inactivation of enzyme activity to prevent oxidation of red stems, but also maximizes the preservation of high amino acid components to prevent high-temperature degradation, thereby increasing the amino acid retention rate of tea during the fixation process.

Description

Technical Field

[0001] This invention relates to the field of tea processing technology, and in particular to a step-temperature controlled manual frying method for Longjing Golden Bud tea. Background Technology

[0002] Golden Bud is a rare, light-sensitive, albino tea tree variety successfully cultivated in my country in recent years. Compared with ordinary green tea varieties, Golden Bud has a unique biochemical composition: its free amino acid content is extremely high, with some data indicating it can reach as high as 9%, far exceeding the 3%–4% amino acid content level of ordinary green tea; while its tea polyphenol content is relatively low, and the phenol-amino acid ratio is significantly lower. This unique biochemical characteristic endows Golden Bud tea with the "three yellow" quality characteristics of "bright yellow dry tea, bright yellow liquor, and pure yellow tea leaves," resulting in a mellow, refreshing, sweet, and aromatic tea. Golden Bud is named for its golden color throughout the year and its precious quality, comparable to gold. The premium tea made from it can fetch over a thousand yuan per kilogram, and at its peak, nearly ten thousand yuan per kilogram, making it a truly "noble tea."

[0003] However, the unique biochemical composition of Golden Bud tea makes its processing requirements extremely stringent. First, its high amino acid content, while giving it a fresh and crisp quality, also brings about heat sensitivity issues—amino acids are easily destroyed by Maillard reactions under high temperatures, leading to a decrease in freshness and a deterioration in aroma. Second, Golden Bud tea leaves are thinner and the internodes of buds are longer, making it less tolerant of temperature and stress during processing than ordinary Longjing green tea varieties, significantly increasing the difficulty of processing. In addition, as a light-sensitive albino variety, Golden Bud tea has abnormal chloroplast development in its albino shoots, with hindered thylakoid and grana formation and a significant reduction in chlorophyll content. This unique cellular structure makes its color change pattern during processing fundamentally different from that of conventional leaf color varieties.

[0004] The processing of Longjing tea mainly includes three core steps: spreading out, pan-frying (fixing and initial shaping), and final pan-frying (further shaping and drying). In the existing technology, the processing technology for ordinary Longjing green tea is relatively mature. The temperature of the pan-frying is usually between 120 and 300℃, and the temperature of the final pan-frying is usually controlled between 60 and 100℃. Generally, constant temperature heating or simple high and low temperature adjustment is used.

[0005] In recent years, there have been some research reports on the processing technology of Golden Bud tea. Some studies have shown that Golden Bud green tea processed by drum fixation has a higher amino acid content than that processed by steam and microwave fixation, and has a mellow and refreshing taste. Dried tea processed by drum fixation has the greenest color, the best aroma, and a distinct chestnut aroma. Other studies have shown that Golden Bud green tea made by pan-frying fixation, straightening the strips, and low-temperature drying has a bright yellow and vibrant appearance, a bright yellow and clear liquor, a fresh and lively aroma, and a fresh, sweet and mellow taste, which best reflects the "three yellows" varietal characteristics of Golden Bud.

[0006] Existing blanching processes mostly employ constant temperature or simple stepped heating, lacking a refined temperature control design to address the high amino acid content and easy inactivation characteristics of golden buds. This makes it difficult to achieve the optimal balance between enzyme activity inhibition and amino acid retention. Although drum blanching can better preserve aroma, its total antioxidant capacity is low. While microwave blanching has the highest total antioxidant capacity, its amino acid content is not as high as that of drum blanching. Therefore, existing processes fail to systematically match the varietal characteristics of golden buds with processing parameters, resulting in the underutilization of their quality potential. Summary of the Invention

[0007] To improve the existing blanching process mentioned above, which mostly uses constant temperature or simple stepped heating, there is a lack of refined temperature control design for the high amino acid content and easy inactivation characteristics of golden buds. It is difficult to achieve the optimal balance between enzyme activity inhibition and amino acid retention. Although drum blanching can better preserve aroma, its total antioxidant capacity is low. Although microwave blanching has the highest total antioxidant capacity, its amino acid content is not as high as that of drum blanching. Therefore, the existing process fails to systematically match the varietal characteristics of golden buds with the processing parameters, resulting in the failure to fully realize its quality potential.

[0008] This invention provides a step-temperature controlled manual frying method for Longjing Golden Bud tea, employing the following technical solution: A step-temperature controlled hand-frying method for Longjing Golden Bud tea includes the following steps: Step 1: Harvesting Process Pick fresh golden buds and leaves that meet the criteria of "one bud and one leaf just beginning to unfold" or "one bud and two leaves just beginning to unfold" after the morning dew dries and before 9:30 a.m. Step 2: Spreading process Spread the freshly picked leaves out to a thickness of 2-3 cm for 2-3 hours, until the moisture content drops to 70%-75%. Step 3: Green Pot Process After spreading out the tea leaves, put them into a wok preheated to 245-255℃ and stir-fry them by hand for 15 minutes to kill the green. During the killing process, keep the wok temperature stable at 245-255℃. Step 4: Final Boiler Process After being roasted in the pan, the tea leaves undergo three stages of manual roasting: Stage 1: The pan temperature is controlled at 175-185℃, and the roasting time is 8-12 minutes; Stage 2: The pan temperature is controlled at 145-155℃, and the roasting time is 5-8 minutes; Stage 3: The pan temperature is controlled at 115-125℃, and the roasting time is 3-5 minutes.

[0009] Optionally, in the above-mentioned step-temperature manual frying method for Longjing Golden Bud Tea, the withering process is divided into two stages: the first stage (3-5 minutes) uses high-frequency frying at a frequency of 60-80 times per minute, and the second stage (10-12 minutes) uses medium-frequency frying at a frequency of 40-50 times per minute.

[0010] Optionally, in the above-mentioned step-temperature manual frying method for Longjing Golden Bud tea, in the final frying process, the frying frequency in the first stage is controlled at 30-40 times per minute, the frying frequency in the second stage is controlled at 50-60 times per minute, and the frying frequency in the third stage is controlled at 20-30 times per minute.

[0011] Optionally, in the above-mentioned step-temperature manual frying method for Longjing Golden Bud Tea, in the final frying process, the first stage uses grasping, shaking, and spreading techniques for frying; the second stage uses stacking, pressing, and pushing techniques for shaping the leaves; and the third stage uses light grasping and light grinding techniques for enhancing aroma.

[0012] Optionally, in the above-mentioned step-temperature controlled manual frying method for Longjing Golden Bud tea, the withering process is carried out using an electromagnetic induction heating drum-type withering machine. The withering machine includes a drum, multiple sets of electromagnetic heating coils surrounding the outer wall of the drum, a temperature sensor, and a temperature controller. The multiple sets of electromagnetic heating coils are distributed in a stepped, non-equidistant manner along the axial direction of the drum, and a low-temperature buffer zone of 10-15cm is provided between adjacent coil sets. The temperature sensor monitors the temperature inside the drum in real time and feeds it back to the temperature controller, which regulates the on / off state of the electromagnetic heating coils to achieve constant temperature withering at 245-255℃.

[0013] Optionally, in the above-mentioned step-temperature controlled manual frying method for Longjing Golden Bud tea, the final frying process is carried out using an electric heating frying machine. The frying machine includes a frying pot body, an electric heating element, an insulation layer, a temperature sensor, and a controller. The electric heating element is located below the frying pot body, the insulation layer is wrapped around the outer periphery of the frying pot body, the temperature sensor is embedded in the bottom of the frying pot body, and the controller adjusts the heating power of the electric heating element according to the real-time temperature feedback from the temperature sensor to achieve step-temperature control of 175-185℃, 145-155℃, and 115-125℃.

[0014] Optionally, in the above-mentioned step-temperature manual frying method for Longjing Golden Bud tea, the frying pan is made of cast iron and the pan wall thickness is 3-5mm.

[0015] Optionally, in the above-mentioned step-temperature manual frying method for Longjing Golden Bud tea, during the spreading process, the leaves are lightly turned every 30 minutes to ensure even water loss from the fresh leaves.

[0016] Optionally, in the above-mentioned step-temperature manual frying method for Longjing Golden Bud tea, the total time of the final frying process is 16 to 25 minutes, and the moisture content of the finished tea is controlled at 5% to 6%.

[0017] Optionally, in the above-mentioned step-temperature manual frying method for Longjing Golden Bud tea, the amount of fresh leaves used per batch is 100-150g.

[0018] In summary, the present invention has at least one of the following beneficial effects: 1. Highly targeted and fully adapted to the characteristics of the Golden Bud variety: This invention is specifically designed for the characteristics of the Golden Bud variety, such as high amino acid content, low tea polyphenol content, thin leaves, and long bud nodes. Through the refined parameter setting of 250℃ high-temperature fixation for 15 minutes, it not only achieves full inactivation of enzyme activity to prevent oxidation of red stems, but also maximizes the preservation of high amino acid components to prevent high-temperature degradation, thereby increasing the amino acid retention rate of tea leaves during the fixation process.

[0019] 2. Differentiated temperature control for significant quality improvement: This invention innovatively adopts a three-stage design for the final roasting process, with a stepped cooling temperature of 180℃→150℃→120℃. This differs from the constant temperature or simple two-stage heating of existing technologies. The first stage involves slow roasting at a high temperature to promote even moisture loss. The second stage involves shaping the tea leaves at a medium temperature to form a flat and straight shape. The third stage involves low temperature to fully enhance the aroma. This three-stage stepped cooling design is fully adapted to the biochemical characteristics of golden buds, ensuring that the tea leaves are in the optimal temperature field at each stage of moisture loss, shaping, and aroma enhancement.

[0020] 3. Precise manual control throughout the entire process, with high flexibility: This invention relies on the operator's sense of touch and experience to control the process at each key stage of the initial roasting and final roasting. Compared with fully automated mechanical processing, it can flexibly adjust the frequency and intensity of stirring according to the real-time changes in the tea leaves' condition during the roasting process, such as moisture content, color, aroma, and elasticity. The initial roasting stage involves high-frequency stirring at 70 times / minute, the later stage at a medium-frequency stirring at 45 times / minute, and the final roasting stage uses segmented frequency designs of 35 times / minute, 55 times / minute, and 25 times / minute respectively. This fully demonstrates the flexibility advantage of manual roasting, which allows for "making tea according to the tea leaves."

[0021] 4. Equipment Innovation, Precise and Stable Temperature Control: This invention has made targeted improvements to the greening and finishing equipment: The electromagnetic induction heating drum-type greening machine adopts multiple sets of electromagnetic heating coils distributed in a stepped, non-equidistant manner along the drum axis, with a 10-15cm low-temperature buffer zone between adjacent coil sets. Combined with temperature sensors and controllers, it achieves precise constant temperature control of 250±2℃, solving the problem of uneven temperature field in traditional greening machines, which is characterized by "overheating at the ends and underheating in the middle". The electric heating finishing machine adopts a 3-5mm thick-walled cast iron pot body, combined with embedded temperature sensors and controllers, to achieve precise control of three-stage stepped temperature, effectively avoiding the impact of temperature fluctuations on quality.

[0022] 5. Superior quality and significantly improved overall quality: The Golden Bud tea produced by the method of this invention has a flat and smooth appearance, a bright golden color, a fresh and lasting aroma, a clear and bright liquor, and a fresh, mellow and sweet taste. It fully embodies the "three yellow" varietal characteristics of Golden Bud, and its overall quality is significantly better than that of tea produced by traditional processes. Attached Figure Description

[0023] Figure 1 This is a process flow diagram of the manual frying method for Longjing Golden Bud Tea of ​​the present invention; Figure 2 This is a graph showing the effect of different fixation temperatures on the amino acid retention rate of Golden Bud tea leaves. Figure 3 This is a comparison chart of the temperature curve of the three-stage stepped cooling method of the present invention and the temperature curve of the traditional hot pot. Detailed Implementation

[0024] The following is in conjunction with the appendix Figures 1-3 The present invention will be described in further detail below.

[0025] Example 1: The present invention provides a step-temperature controlled manual frying method for Longjing Golden Bud tea, comprising the following steps: Step 1: Harvesting Process Pick fresh golden buds and leaves that meet the criteria of "one bud and one leaf just beginning to unfold" or "one bud and two leaves just beginning to unfold" after the morning dew dries and before 9:30 a.m. Step 2: Spreading process Spread the freshly picked leaves out to a thickness of 2-3 cm for 2-3 hours, until the moisture content drops to 70%-75%. Step 3: Green Pot Process After spreading out the tea leaves, put them into a wok preheated to 245-255℃ and stir-fry them by hand for 15 minutes to kill the green. During the killing process, keep the wok temperature stable at 245-255℃. Step 4: Final Boiler Process After being roasted in the pan, the tea leaves undergo three stages of manual roasting: Stage 1: The pan temperature is controlled at 175-185℃, and the roasting time is 8-12 minutes; Stage 2: The pan temperature is controlled at 145-155℃, and the roasting time is 5-8 minutes; Stage 3: The pan temperature is controlled at 115-125℃, and the roasting time is 3-5 minutes.

[0026] It should be noted that in the blanching process, the blanching process is divided into two stages: the first stage, which lasts for 3 to 5 minutes, uses high-frequency stirring at a frequency of 60 to 80 times per minute, and the second stage, which lasts for 10 to 12 minutes, uses medium-frequency stirring at a frequency of 40 to 50 times per minute.

[0027] In the final stir-frying process, the stirring frequency is controlled at 30-40 times per minute in the first stage, 50-60 times per minute in the second stage, and 20-30 times per minute in the third stage.

[0028] In the process of frying, the first stage uses the techniques of grasping, shaking, and spreading to stir-fry; the second stage uses the techniques of stacking, pressing, and pushing to shape the dough; and the third stage uses the techniques of light grasping and light grinding to enhance the aroma.

[0029] The green pot process is carried out using an electromagnetic induction heating drum-type green pot fixing machine. This green pot fixing machine includes a drum, multiple sets of electromagnetic heating coils surrounding the outer wall of the drum, a temperature sensor, and a temperature controller. The multiple sets of electromagnetic heating coils are distributed in a stepped non-equal spacing along the axial direction of the drum. A low temperature buffer zone of 10-15cm is provided between adjacent coil sets. The temperature sensor monitors the temperature inside the drum in real time and feeds it back to the temperature controller. The temperature controller regulates the on and off of the electromagnetic heating coils to achieve constant temperature green pot fixing of 245-255℃.

[0030] The frying process is carried out using an electric frying machine, which includes a frying pot body, an electric heating element, an insulation layer, a temperature sensor, and a controller. The electric heating element is located below the frying pot body, the insulation layer is wrapped around the outer periphery of the frying pot body, the temperature sensor is embedded in the bottom of the frying pot body, and the controller adjusts the heating power of the electric heating element according to the real-time temperature feedback from the temperature sensor to achieve stepped cooling control of 175-185℃, 145-155℃, and 115-125℃.

[0031] The wok is made of cast iron, and the wall thickness is 3-5mm.

[0032] During the spreading process, the leaves are turned over lightly every 30 minutes to ensure even water loss.

[0033] The total time for the final firing process is 16 to 25 minutes, and the moisture content of the finished tea is controlled at 5% to 6%.

[0034] The amount of fresh leaves used for each batch of processing is 100-150g.

[0035] Example 2: This example provides a method for manually frying Longjing Golden Bud tea leaves, with production scaled at 100g of fresh leaves per batch.

[0036] Raw material preparation: Harvesting process: The harvesting time is from 7:00 to 8:30 am before Qingming Festival. The harvesting standard is one bud and one newly unfolded leaf, that is, each bud with a newly unfolded tender leaf. When harvesting, handle the leaves gently to avoid pinching the leaves with your fingernails. After harvesting, place the fresh leaves in a well-ventilated bamboo basket to avoid direct sunlight and compression. During the harvesting process, strictly distinguish fresh leaves of different tenderness to ensure that the tenderness of each batch of fresh leaves is consistent. A total of 100g of fresh leaves are harvested.

[0037] Preparation process: Spreading process: Spread the freshly picked leaves evenly on a bamboo tray, with a thickness of 2-3 cm. Place the bamboo tray in a well-ventilated and shady place with a temperature of 20-25℃ and a relative humidity of 60%-70% for 2.5 hours. During the spreading process, turn the leaves lightly every 30 minutes to ensure that the leaves lose water evenly. After spreading, the moisture content of the fresh leaves will drop to about 72%, the leaves will become soft and lose their luster, and the grassy smell will be partially released, giving off a faint fragrance.

[0038] Green pot process: The green pot is made using an electromagnetic induction heating drum-type green pot machine. The green pot machine includes a drum, three sets of electromagnetic heating coils surrounding the outer wall of the drum, a temperature sensor and a temperature controller. The drum is made of cast iron with a wall thickness of 4mm. The three sets of electromagnetic heating coils are distributed in a stepped non-equal interval along the axis of the drum, and a 12cm low temperature buffer zone is provided between adjacent coil sets.

[0039] After spreading the tea leaves, they are put into the drum. The electromagnetic heating system is activated to raise the temperature inside the drum to 250°C and keep it constant. During the fixation process, the operator stirs the tea leaves by hand to ensure that they are heated evenly. The first 4 minutes of fixation are done at a high frequency of 70 times per minute to quickly raise the temperature of the tea leaves and deactivate the enzymes. The last 11 minutes are done at a medium frequency of 45 times per minute to ensure that the moisture in the tea leaves evaporates evenly. At the same time, the initial shaping of the tea leaves begins. The total fixation time is 15 minutes.

[0040] The temperature sensor monitors the temperature inside the drum in real time and feeds it back to the temperature controller. When the temperature is below 248℃, the temperature controller activates the electromagnetic heating coil in the corresponding area to supplement the heat. When the temperature is above 252℃, the heating stops to ensure that the blanching temperature is stable at 250±2℃.

[0041] The state of tea leaves at the end of the processing: the color changes from bright yellow to golden yellow with a hint of green, the leaves wither and soften, the stems shrink, the tea strips begin to flatten, the grassy smell disappears, and a tender chestnut aroma is emitted.

[0042] The final roasting process: The tea leaves after the initial roasting are transferred to an electric roasting machine for final roasting. The roasting machine includes a cast iron roasting pot body, an electric heating tube located below the pot body, an insulation layer wrapped around the outside of the pot body, a temperature sensor and controller embedded at the bottom of the pot body, and the pot wall thickness is 4mm.

[0043] The hot-pot process is divided into three stages: The first stage is slow and even frying: the pan temperature is controlled at 180℃, the frying frequency is 35 times per minute, and the frying time is 10 minutes. This stage mainly uses light techniques such as grasping, shaking and spreading to make the moisture inside and outside the tea leaves evenly dissipate and the leaves soften further.

[0044] The second stage of shaping: The pan temperature is controlled at 150℃, the stirring frequency is 55 times per minute, and the frying time is 6 minutes. In this stage, the tea leaves are shaped by pressing, pushing and pressing techniques, and the pressure is gradually increased. The tea leaves gradually form a flat and straight Longjing shape.

[0045] The third stage is aroma enhancement: the pan temperature is controlled at 120℃, the stirring frequency is 25 times per minute, and the stir-frying time is 4 minutes. This stage mainly uses gentle grasping and grinding techniques. When the tea leaves are flat and smooth, golden and bright in color, and have a fresh and lasting aroma, they are removed from the pan. The total time for the final stir-fry is 20 minutes.

[0046] The controller adjusts the heating power of the heating element based on the real-time temperature feedback from the temperature sensor to ensure that the pot temperature remains stable within ±2℃ of the set value at each stage. Throughout the entire process of frying, the operator judges the moisture content and elasticity of the tea leaves by touch and adjusts the stirring force and frequency in real time.

[0047] Product quality inspection results: Example 3: Comparative Test of Blanching Temperature This embodiment examines the effect of different fixation temperatures on the quality of Golden Bud tea leaves; other process parameters are the same as in Embodiment 2.

[0048] Experimental Groups: Group A: Blanching temperature 190℃, blanching time 15 minutes Group B: Blanching temperature 220℃, blanching time 15 minutes Group C: Blanching temperature 250℃, blanching time 15 minutes (Example 2) Group D: Blanching temperature 280℃, blanching time 15 minutes Test results: Conclusion: When the fixation temperature is 250℃, the tea leaves have the best golden and bright color, the highest amino acid content of 5.8%, the highest amino acid retention rate of 76.3%, the lowest phenol-amino acid ratio of 3.21, and the highest sensory evaluation score of 92.6 points. When the temperature is below 250℃, enzyme activity is not sufficiently inhibited, and the tea leaves have a grassy smell. When the temperature is above 250℃, amino acid loss is significant, and the tea leaves have scorched edges and a high-fired taste. Therefore, 250℃ is determined to be the optimal fixation temperature for golden buds.

[0049] Example 4: Comparative Test of Temperature Gradient in Boiling Furnace This embodiment examines the effects of different firing temperature gradients on the quality of Golden Bud tea leaves; other process parameters are the same as in Embodiment 2.

[0050] Experimental Groups: Group A: Stir-fry at a constant temperature of 100℃ for 20 minutes. Group B: Two-stage wok, stir-fry at 150℃ for 12 minutes → stir-fry at 100℃ for 8 minutes Group C: Three-stage stepped cooling: 180℃ for 10 minutes → 150℃ for 6 minutes → 120℃ for 4 minutes (Example 2) Test results: Conclusion: The tea produced by the three-stage stepped cooling process has the best overall quality. The first stage at a high temperature of 180℃ is conducive to rapid moisture loss and promotes the transformation of aroma precursors; the second stage at a medium temperature of 150℃ is conducive to shaping and setting; and the third stage at a low temperature of 120℃ is conducive to locking in and enhancing the aroma. The three-stage design ensures that the tea is in the optimal temperature field in each stage of moisture loss, shaping, and aroma enhancement.

[0051] Example 5: Comparison Test of Stir-frying Frequency This embodiment examines the impact of different stirring frequencies at each stage of the initial and final stir-frying processes on the quality of Golden Bud tea.

[0052] Comparison of different cooking stages: Comparison of the final cooking stages: Conclusion: The stirring frequency of 70 times / minute in the first stage and 45 times / minute in the second stage of the initial stirring stage can ensure rapid deactivation of enzyme activity and avoid breakage. The segmented frequency design of 35 times / minute, 55 times / minute and 25 times / minute in the final stirring stage allows the tea to achieve its respective goals in the three stages of dehydration, shaping and aroma enhancement, and the overall breakage rate is controlled below 3%, which is significantly better than the 5% to 8% of the traditional process.

[0053] Example 6: Comparative Test with Existing Processes This embodiment compares Embodiment 2 of the present invention with the traditional Longjing green tea frying process. The traditional process parameters are: initial pan temperature 220℃, fixation time 12 minutes; final pan temperature 100℃, constant temperature frying for 20 minutes.

[0054] Comparison of test results: Conclusion: Compared with traditional processes, the free amino acid content of the golden bud tea prepared by the method of this invention is increased by 26.1%, the tea polyphenol content is reduced by 12.7%, the phenol-to-amino acid ratio is reduced by 30.7%, the amino acid retention rate is increased by 26.1%, and the sensory evaluation score is increased by 7.3 points. The method of this invention has significant advantages in preserving the high amino acid quality of golden buds, reducing bitterness and astringency, and presenting the "three yellow" color.

[0055] The above are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A step-temperature controlled manual frying method for Longjing Golden Bud tea, characterized by: Includes the following steps: Step 1: Harvesting Process Pick fresh golden buds and leaves that meet the criteria of "one bud and one leaf just beginning to unfold" or "one bud and two leaves just beginning to unfold" after the morning dew dries and before 9:30 a.m. Step 2: Spreading process Spread the freshly picked leaves out to a thickness of 2-3 cm for 2-3 hours, until the moisture content drops to 70%-75%. Step 3: Green Pot Process After spreading out the tea leaves, put them into a wok preheated to 245-255℃ and stir-fry them by hand for 15 minutes to kill the green. During the killing process, keep the wok temperature stable at 245-255℃. Step 4: Final Boiler Process After being roasted in the pan, the tea leaves undergo three stages of manual roasting: Stage 1: The pan temperature is controlled at 175-185℃, and the roasting time is 8-12 minutes; Stage 2: The pan temperature is controlled at 145-155℃, and the roasting time is 5-8 minutes; Stage 3: The pan temperature is controlled at 115-125℃, and the roasting time is 3-5 minutes.

2. The step-temperature manual frying method for Longjing Golden Bud tea according to claim 1, characterized in that: In the greening process, the greening process is divided into two stages: the first stage is 3 to 5 minutes of high-frequency stirring, with a frequency of 60 to 80 times per minute, and the second stage is 10 to 12 minutes of medium-frequency stirring, with a frequency of 40 to 50 times per minute.

3. The step-temperature manual frying method for Longjing Golden Bud tea according to claim 1, characterized in that: In the above-mentioned stir-frying process, the stirring frequency is controlled at 30-40 times per minute in the first stage, 50-60 times per minute in the second stage, and 20-30 times per minute in the third stage.

4. The step-temperature manual frying method for Longjing Golden Bud tea according to claim 1, characterized in that: In the above-mentioned cooking process, the first stage uses grasping, shaking, and spreading techniques for stir-frying; the second stage uses stacking, pressing, and pushing techniques for shaping the strips; and the third stage uses light grasping and grinding techniques for enhancing aroma.

5. The step-temperature manual frying method for Longjing Golden Bud tea according to claim 1, characterized in that: The greening process is carried out using an electromagnetic induction heating drum-type greening machine. The greening machine includes a drum, multiple sets of electromagnetic heating coils surrounding the outer wall of the drum, a temperature sensor, and a temperature controller. The multiple sets of electromagnetic heating coils are distributed in a stepped, non-equidistant manner along the axial direction of the drum. A low-temperature buffer zone of 10-15cm is provided between adjacent coil sets. The temperature sensor monitors the temperature inside the drum in real time and feeds it back to the temperature controller. The temperature controller regulates the on / off state of the electromagnetic heating coils to achieve constant temperature greening at 245-255℃.

6. The step-temperature manual frying method for Longjing Golden Bud tea according to claim 1, characterized in that: The hot pot process is carried out using an electric hot pot machine, which includes a cooking pot body, an electric heating element, an insulation layer, a temperature sensor, and a controller. The electric heating element is located below the cooking pot body, the insulation layer is wrapped around the outer periphery of the cooking pot body, the temperature sensor is embedded in the bottom of the cooking pot body, and the controller adjusts the heating power of the electric heating element according to the real-time temperature feedback from the temperature sensor to achieve stepped cooling control of 175-185℃, 145-155℃, and 115-125℃.

7. The step-temperature manual frying method for Longjing Golden Bud tea according to claim 6, characterized in that: The wok is made of cast iron and has a wall thickness of 3-5 mm.

8. The step-temperature manual frying method for Longjing Golden Bud tea according to claim 1, characterized in that: During the spreading process, the leaves are turned over lightly every 30 minutes to ensure even water loss.

9. The step-temperature manual frying method for Longjing Golden Bud tea according to claim 1, characterized in that: The total time for the final firing process is 16 to 25 minutes, and the moisture content of the finished tea is controlled at 5% to 6%.

10. The step-temperature manual frying method for Longjing Golden Bud tea according to claim 1, characterized in that: The amount of fresh leaves used for each batch of processing is 100-150g.

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