Preparation method of gem type yellow tea

Abstract

The invention provides a preparation method of gem type yellow tea, and relates to the technical field of tea processing. The preparation method of the gem type yellow tea comprises the following steps: S1, pretreating fresh tea leaves serving as a raw material by a spreading and airing process under the control of a specific temperature; s2, fixing effective components in the fresh tea leaves by adopting low-temperature long-time fixation; s3, heaping for yellowing based on a micro-damp-heat action principle to promote generation of aroma substances, prevent excessive oxidation and guarantee unique taste; and S4, performing fine rolling to form a gemstone-shaped tea shape, and further exciting inclusions to seep so as to enhance the taste complexity. Pretreatment, low-temperature fixation, heaping for yellowing and fine rolling of raw material tea are realized through accurate temperature and time control, so that high-quality tea leaves with unique flavor and good morphological characteristics are obtained, and modern technical innovation elements are combined on the basis of retaining the advantages of a classical yellow tea process. And the characteristics of the yellow tea are further strengthened and displayed while stable supply of the product is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of tea processing, in particular to a method for making gem-type yellow tea. Background Art

[0002] Yellow tea is a lightly fermented tea, and its processing technology is similar to that of green tea, except that a "yellowing" process is added before or after the drying process to promote partial oxidation of polyphenols such as chlorophyll. Its processing method is similar to that of green tea, and its production process is: fresh leaves withering, rolling, and drying. The withering, rolling, and drying processes of yellow tea are similar to those of green tea. The most important process is yellowing, which is the key to forming the characteristics of yellow tea. The final product has gained a gem-like reputation for its outstanding color, aroma, and shape.

[0003] This method especially focuses on improving certain steps in the traditional yellow tea process to preserve the unique aroma and flavor of tea, while striving to achieve a more balanced and coordinated effect. In order to solve the problem of how to solve the conflict between tea aroma and taste in the traditional yellow tea production process, some improvement measures are taken in the production process of this gem-type yellow tea, such as precise control of humidity and time during the steaming period, so that the tea soup not only maintains a fresh aroma and pure taste, but also adds a unique gem luster and delicate taste, thereby solving the above contradictions and improving the overall taste level and aesthetic experience. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a method for preparing gem-type yellow tea, which solves the problem that it is difficult to obtain both aroma and flavor in the traditional yellow tea preparation process.

[0005] To achieve the above objectives, the present invention is implemented through the following technical scheme: a method for making gem-type yellow tea, comprising the following steps:

[0006] S1. Pre-treating raw tea leaves by spreading and airing process under specific temperature control;

[0007] S2. Use low temperature and long time to fix the active ingredients in fresh tea leaves;

[0008] S3. Based on the principle of micro-humid heat, the aroma is yellowed to promote the generation of aroma substances while preventing excessive oxidation to ensure a unique taste;

[0009] S4. Use fine rolling to form a gem-like tea shape and further stimulate the inclusions to seep out to enhance the complexity of the taste.

[0010] Preferably, the S1 step is specifically as follows:

[0011] Control the temperature in the drying room between 18 and 22 degrees Celsius;

[0012] Spread the fresh leaves evenly to a thickness of 2 to 3 cm;

[0013] Use circulating air equipment to keep the drying environment slightly humid;

[0014] The continuous drying time shall not be less than 6 hours but not more than 12 hours;

[0015] The temperature and humidity changes during the drying process are recorded and adjusted through a monitor to ensure stability and controllability.

[0016] Preferably, the S2 step is specifically as follows:

[0017] In the initial heating stage, the temperature is slowly raised to 60°C to 70°C to reduce mechanical damage;

[0018] Maintaining this temperature range stably for 2 to 5 hours promotes the locking of beneficial substances;

[0019] The infrared sensor automatically adjusts the heater power to ensure the uniformity of the killing;

[0020] Ventilate regularly to remove excess steam and reduce the chance of oxidation;

[0021] Use stirring fan blades to turn the fresh leaves to avoid quality deterioration due to overheating.

[0022] Preferably, the S3 step is specifically as follows:

[0023] Use a temperature and humidity control box to create a small environment with a temperature of 45 degrees Celsius and a humidity of more than 60% RH;

[0024] Keep it in this environment for at least 8 hours to ensure that the aroma substances are fully formed;

[0025] Prevent direct sunlight and use sunshade cloth or closed box to reduce external oxygen exchange;

[0026] Open the micro vents regularly to discharge excess moisture and prevent mold growth;

[0027] Monitor the temperature and humidity conditions in a timely manner and adjust the moisture content in the yellow box to an appropriate level to ensure consistent quality.

[0028] Preferably, the S4 step is specifically as follows:

[0029] Press lightly and then harder to gradually shape the gemstone until the shape is close to the outline of the gemstone.

[0030] Adjust the rotation direction of the drum to make the friction between tea particles more effective and reduce the risk of breakage;

[0031] Gradually reduce the pressure inside the tumbling device so that the substance inside can be released naturally without affecting the appearance;

[0032] Adding a standing step utilizes the heat of the tea leaves themselves to help the flavor develop more distinctively and lastingly.

[0033] Remove the excess juice remaining inside and outside the kneaded mass through a timed vibrating machine to prevent over-fermentation from affecting the final drinking effect.

[0034] Preferably, in the step S3, the yellowing is carried out based on the principle of mild heat and humidity action as follows:

[0035] Mild wet preheating treatment step;

[0036] Temperature and humidity regulation step;

[0037] Quality change monitoring step;

[0038] Oxidation state adjustment step.

[0039] Preferably, in the mild wet preheating treatment step, when the microenvironment temperature and humidity reach T_min < microenvironment temperature and humidity < T_max, the yellowing process is started, where T_min and T_max are the lower and upper limit values of temperature and humidity respectively;

[0040] Further set the initial temperature and humidity for yellowing;

[0041] Set the temperature and humidity increase rate according to the preheating time;

[0042] Keep the temperature steadily within the optimal preheating point range.

[0043] Preferably, in the temperature and humidity regulation step, when the monitoring point M reaches the preset threshold, adjust the temperature and humidity settings of the yellowing box to reach the target temperature and humidity T_target, and change the fine-tuning ratio to the optimal ratio when M ≤ T_target;

[0044] Maintain the temperature within the target temperature ± allowable floating temperature ΔT fluctuation range as the target temperature ± ΔT;

[0045] Adjust the ventilation volume so that the internal circulation meets the standard, and the standard is the circulation condition within the range of X cubic meters per minute ± 10%;

[0046] Start recording the yellowing time M_time when it is confirmed that the temperature and humidity reach the target range.

[0047] Preferably, in the quality change monitoring step, start the intervention measure when the change rate of the quality monitoring threshold exceeds the critical value, and C_th is the critical point of the quality change rate;

[0048] Take real-time samples of color, aroma, etc., and analyze the change curve;

[0049] If the color deviates from the set range, perform color fine-tuning until it returns to the desired range, and the range is S_min~S_max;

[0050] Adjustments are made according to changes in aroma concentration to ensure that the aroma texture is not destroyed. The ideal range of aroma is between Y_min and Y_max.

[0051] Preferably, in the oxidation state adjustment step, when the measured polyphenol change index is lower than the minimum change amount, the wet hot water vapor is adjusted to activate the catalytic oxidation, and the adjustment procedure is started when MP_level≤MP_threshold;

[0052] Adjust the water vapor saturation to ensure that the polyphenols change smoothly and remain stable in the range of R_min to R_max, where R is the moisture saturation ratio;

[0053] Optimize water distribution to promote aroma generation. After optimization, the activity level of water molecules should vary within the Q standard by ±10%;

[0054] Monitor the degree of oxidation during the entire yellowing stage and keep it within the target range, i.e., O_min ≤ degree of oxidation ≤ O_max, and maintain the target value at O_level.

[0055] The present invention provides a method for making gem-type yellow tea, which has the following beneficial effects:

[0056] 1. The present invention improves the problems of aroma loss and monotonous tea flavor encountered in the production process of traditional yellow tea, while improving the ornamental and taste experience of tea. This method realizes the pretreatment, low-temperature killing, yellowing and fine rolling of raw tea through precise temperature and time control, so as to obtain high-quality tea with both unique flavor and good morphological characteristics. On the basis of retaining the advantages of classic yellow tea process, it combines contemporary technological innovation elements, and realizes that the characteristics of yellow tea itself are further strengthened and displayed while ensuring a stable supply of products. It has both a unique fragrance and a rich aftertaste, and also increases the visual beauty of the finished product. DETAILED DESCRIPTION

[0057] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0058] Example:

[0059] The embodiment of the present invention provides a method for preparing gemstone yellow tea, comprising the following steps:

[0060] S1. Take the small buds picked around Qingming as raw materials, spread them thinly in a ventilated and dark place at 18 to 22 degrees Celsius. This temperature control measure can ensure that the fresh leaves gradually lose water without rapid aging. The thickness of the thin spread is 2 to 3 cm. Such a thickness can not only promote moderate ventilation and natural evaporation of water between tea leaves, but also facilitate the changes in materials in tea leaves, maintain the drying efficiency, and keep the indoor humidity at about 75%. After about 6-12 hours, the fresh leaves show a significant softening state and emit a faint fragrance. At this time, you can enter the next process. During the drying process, maintain a suitable micro-humidity state in the environment, thereby accelerating the enzyme action in the fresh leaves to facilitate the quality control of the subsequent production process, avoiding over-drying and causing the tea leaves to dry and lose activity or excessive moisture. The adverse effects such as excessive fermentation. This drying method can not only evaporate water moderately and adjust the enzyme activity in the leaves to achieve a certain degree of start-up effect, but more importantly, it can effectively control the degree of fermentation and create conditions for the later yellowing process. The tea leaves treated in this way are more flexible, which is helpful for the subsequent withering process.

[0061] S2. The fresh leaves that have been properly withered are heated initially, and the temperature is slowly raised to 60-70 degrees Celsius to prevent the tea leaves from being damaged in any way. Entering the next stable holding period, it is necessary to ensure that the temperature remains stable. Heating is performed for 2 to 5 hours to help fix the beneficial compounds, which can improve the overall aroma and texture characteristics of the product; the heating power is adjusted based on the data of the infrared sensor to maintain uniform heat distribution and precise temperature control; forced ventilation measures are taken at appropriate times and durations to remove the additional steam generated while limiting the occurrence of oxidation to maintain the freshness and unique aroma of the tea leaves from being lost due to increased air contact; stirring blades are used to move back and forth to prevent quality changes caused by heat, and the tea leaves are constantly and gently pushed during the entire manufacturing process to ensure that the fresh leaves at each level are properly heated. At this temperature, the oxidation process can be effectively prevented, and the rapid failure of active enzymes at high temperatures can be avoided, resulting in damage to the flavor of the tea leaves. The relatively slow temperature treatment also helps to better reflect some beneficial chemical changes and preserve the original fresh tea aroma.

[0062] S3. During the yellowing process, the tea leaves that have just been preliminarily processed are placed in a breathable container or a special cloth bag and sealed for at least 8 hours to allow the tea leaves to undergo internal transformation in a storage environment at 45 degrees Celsius and humidity above 60% RH; shielding methods such as using sunshade cloth or other sealing devices to block light, and control the oxygen in and out of the yellowing box; every two to four hours, the exhaust valve needs to be opened to release the saturated hot and humid air in the temperature and humidity control box, which can ensure that the humidity is not too high to cause the tea leaves to ferment out of control and damage its quality, and can also reduce the risk of mold; during the entire yellowing cycle, it is necessary to regularly observe the state of the temperature and humidity control box and make fine adjustments in time to ensure that the tea leaves can continue to be kept under stable temperature and humidity conditions. In this stage, the slightly hot and humid environment is used to induce the mutual changes between amino acid compounds and chlorophyll, etc., to promote the yellowing reaction of the tea leaves, and further produce new aroma precursors.

[0063] S4. The processed tea leaves are initially shaped. In this stage, the technique of switching from light to heavy is used to continuously adjust and shape them into a special shape similar to the outline of a gemstone. In order to make the particles in the tea interact with each other and reduce excessive breakage caused by the operation process, the rolling direction of the machine drum is changed to ensure that the desired effect can be achieved through mutual friction while maintaining the integrity of the raw materials. In the process of processing yellow tea, the pressure value of the air tightness inside the equipment will be continuously reduced to ensure that the flavor substances can be released at the right time without causing the tea leaves themselves to deform, so that the shape is better maintained and the flavor characteristics are more prominent. An additional static period is added to allow the tea leaves that have taken shape to balance their temperature by themselves during this period of time, allowing the residual heat to continue to act on themselves to help form a more intense, layered and durable taste. Vibration technology is used to help remove excess water or juice that does not need to be retained on the tea body after kneading, to prevent excessive liquid from causing unnecessary oxidation or quality deterioration.

[0064] While retaining the advantages of classic yellow tea craftsmanship, it combines elements of contemporary technological innovation to ensure a stable supply of products while further strengthening and displaying the characteristics of yellow tea itself. It has both a unique fragrance and a rich aftertaste, while also increasing the visual beauty of the finished product.

[0065] The yellowing process based on the principle of slightly moist heat includes: slightly moist preheating treatment step, temperature and humidity control step, quality change monitoring step and oxidation state adjustment step.

[0066] In the slightly wet preheating treatment step, when the microenvironment temperature and humidity reach T_min < microenvironment temperature and humidity < T_max, the yellowing process is started, where T_min and T_max are the lower limit value and the upper limit value of the temperature and humidity respectively; the initial temperature and humidity for yellowing are further set; the temperature and humidity increase rate is set according to the preheating time; the temperature is stably maintained within the optimal preheating point range.

[0067] In the temperature and humidity control step, when the monitoring point M reaches the preset threshold, the temperature and humidity settings of the yellowing box are adjusted to reach the target temperature and humidity T_target. When M ≤ T_target, the fine-tuning ratio is changed to the optimal ratio; the temperature is maintained within the fluctuation range of the target temperature ± the allowable floating temperature ΔT, which is the target temperature ± ΔT; the ventilation volume is adjusted to make the internal circulation meet the standard, and the standard is the circulation condition within the range of X cubic meters per minute ± 10%; when it is confirmed that the temperature and humidity reach the target range, the yellowing time record M_time is started.

[0068] In the quality change monitoring step, when the change rate of the quality monitoring threshold exceeds the critical value, the intervention measure is started, and C_th is the critical point of the quality change rate; real-time sampling is carried out for color, aroma, etc., and the change curve is analyzed; if the color deviates from the set range, color fine-tuning is carried out until it returns to the desired range, and the range is S_min to S_max; adjustment measures are carried out according to the change of the aroma concentration to ensure that the aroma texture is not damaged, and the ideal range of the aroma is between Y_min and Y_max.

[0069] In the oxidation state adjustment step, when the measured polyphenol change index is lower than the minimum change amount, the wet hot water vapor is adjusted to activate the catalytic oxidation effect. When MP_level ≤ MP_threshold, the adjustment program is started; the water vapor saturation is adjusted to ensure the stable change of polyphenols, and it is stably maintained within the range of R_min to R_max, where R is the wet saturation ratio; the water distribution is optimized to promote the generation of aroma, and the active level of water molecules after optimization should change within the Q standard ± 10%; the oxidation degree of the entire yellowing stage is monitored and maintained within the target range, that is, O_min ≤ oxidation degree ≤ O_max, and the target value is maintained as O_level.

[0070] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing gemstone yellow tea, characterized in that: It includes the following steps: S1. Pretreat the fresh tea leaves through a withering process under specific temperature control; S2. Fix the active ingredients in the fresh tea leaves by using low-temperature and long-time pan-firing; S3. Carry out yellowing based on the principle of micro-thermo-humid action to promote the formation of aroma substances while preventing excessive oxidation to ensure a unique taste; S4. Use fine rolling to form a gem-like tea shape and further stimulate the exudation of inclusions to enhance the taste complexity.

2. The method for making gem-type yellow tea according to claim 1, characterized in that: The specific steps of step S1 are as follows: Control the temperature in the withering room between 18 and 22 degrees Celsius; Evenly spread the fresh leaves into a thickness of 2 to 3 centimeters; Use a circulating air device to keep the withering environment slightly humid; The continuous withering duration is not less than 6 hours but not more than 12 hours; Record and adjust the temperature and humidity changes during the withering process through a monitor to ensure stable controllability.

3. The method for making gem type yellow tea according to claim 1, characterized in that: The specific steps of step S2 are as follows: In the initial heating stage, the temperature is slowly raised to 60 to 70 degrees Celsius to reduce mechanical damage; Maintain this temperature range steadily for 2 to 5 hours to promote the locking of beneficial substances; Automatically adjust the heater power by means of infrared induction to ensure the evenness of pan-firing; Ventilate regularly to discharge excess steam and reduce the chance of oxidation; Use a stirring fan blade to turn the fresh leaves to avoid quality deterioration due to overheating.

4. The method for making gem-type yellow tea according to claim 1, characterized in that: The specific steps of step S3 are as follows: Use a temperature and humidity control box to create a small environment with a temperature of 45 degrees Celsius and a humidity of more than 60% RH for yellowing storage; Retain in this environment for at least 8 hours to ensure sufficient formation of aroma substances; Prevent direct sunlight and use a sunshade cloth or a closed box to reduce external oxygen exchange; Open the micro-ventilation holes regularly to discharge excess moisture and prevent mold growth; Timely monitor the temperature and humidity conditions and adjust the moisture content in the yellowing box to an appropriate level to ensure consistent quality.

5. The method for making gem type yellow tea according to claim 1, characterized in that: The specific steps of step S4 are as follows: First, apply light pressure and then heavy pressure to gradually shape until the shape is close to the gem contour; Adjust the rotation direction of the roller to make the friction between tea particles more effective and reduce the risk of fragmentation; Gradually reduce the pressure inside the rolling and kneading equipment so that the internal substances are naturally released without affecting the appearance; Increase the static step and use the heat of the tea leaves themselves to help the flavor develop more layered and lasting; Remove the residual excess juice inside and outside the kneaded mass through a timed vibrator to prevent over-fermentation from affecting the final drinking effect.

6. The method for making gem type yellow tea according to claim 1, characterized in that: In step S3, the yellowing based on the principle of micro-thermo-humid action is specifically as follows: Micro-wet preheating treatment step; Temperature and humidity control step; Quality change monitoring step; Oxidation state adjustment step.

7. The method for making gem type yellow tea according to claim 6, characterized in that: In the micro-wet preheating treatment step, when the micro-environment temperature and humidity reach T_min < micro-environment temperature and humidity < T_max, start the yellowing process, where T_min and T_max are the lower limit value and upper limit value of temperature and humidity respectively; Further set the initial temperature and humidity for yellowing; Set the temperature and humidity increase rate according to the preheating time; The temperature is stably maintained within the optimal preheating point range.

8. The method for making gem type yellow tea according to claim 6, characterized in that: In the temperature and humidity control step, when the monitoring point M reaches the preset threshold, adjust the temperature and humidity settings of the yellowing box to reach the target temperature and humidity T_target, and when M ≤ T_target, change the fine-tuning ratio to the optimal ratio; Maintain the temperature within the target temperature ± allowable floating temperature ΔT fluctuation range as the target temperature ± ΔT; Adjust the ventilation volume so that the internal circulation meets the standard flow conditions within the range of X cubic meters / minute ±10%; When the temperature and humidity reach the target range, start recording the yellowing time M_time.

9. The method for making gem type yellow tea according to claim 6, characterized in that: In the quality change monitoring step, intervention measures are initiated when the quality monitoring threshold change rate exceeds a critical value, and C_th is the critical point of the quality change rate; Take real-time samples of color, aroma, etc. and analyze the change curve; If the color deviates from the set range, fine-tune the color until it returns to the expected range, which is S_min to S_max; Adjustments are made according to changes in aroma concentration to ensure that the aroma texture is not destroyed. The ideal range of aroma is between Y_min and Y_max.

10. The method for making gem type yellow tea according to claim 6, characterized in that: In the oxidation state adjustment step, when the measured polyphenol change index is lower than the minimum change amount, the wet hot water vapor is adjusted to activate the catalytic oxidation, and when MP_level≤MP_threshold, the adjustment procedure is started; Adjust the water vapor saturation to ensure that the polyphenols change smoothly and remain stable in the range of R_min to R_max, where R is the moisture saturation ratio; Optimize water distribution to promote aroma generation. After optimization, the activity level of water molecules should vary within the Q standard by ±10%; Monitor the degree of oxidation during the entire yellowing stage and keep it within the target range, i.e., O_min ≤ degree of oxidation ≤ O_max, and maintain the target value at O_level.