Preparation method of oolong tea based on medium and small leaf raw materials and oolong tea
Through specific preparation methods, the problems of small and medium-sized leaf tea in oolong tea processing were solved, and the production of small and medium-sized leaf oolong tea that meets the oolong tea standards was achieved, the production areas and tea varieties of oolong tea raw materials were expanded, and the quality and taste of the tea were improved.
Patent Information
- Application Number
- CN202510809306.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-17
- Publication Date
- 2025-08-01
AI Technical Summary
Small and medium-sized teas cannot meet the quality standards of oolong tea during processing, resulting in limited application scope. The main problems are thin blade stratum corneum, low mechanical strength of cell walls, difficult to regulate oxidation products, high amino acid loss rate, and high volatility rate of aroma components.
Specific preparation methods are adopted, including picking, withering, greening, finishing, wind selection, moistening and rolling, baking, etc., by controlling the moisture content and temperature of the tea leaves, a composite withering process is formed, and rolling and baking is formed in segments to form a small and medium-sized leaf oolong tea that meets the oolong tea standards.
The processing breakthrough of small and medium-sized oolong tea has been achieved, the raw material production area of oolong tea has been expanded, the variety of tea has been enriched, and the uniformity and taste of product quality has been improved. The tea has a natural floral and honey-flavored taste after brewing.
Smart Images
Figure CN120391535A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of tea processing, and particularly relates to a method for preparing oolong tea based on medium and small leaf tea raw materials and the oolong tea. Background Art
[0002] Oolong tea, also known as qing tea, semi-fermented tea and fully fermented tea, has many varieties. It is a tea variety with distinct Chinese characteristics among several major tea categories in China. It is made through processes such as picking, withering, shaking, stir-frying, rolling, and baking. After tasting oolong tea, the fragrance lingers on the teeth and cheeks, and the aftertaste is sweet and fresh. Its pharmacological effects are prominently manifested in aspects such as decomposing fat, losing weight and keeping fit.
[0003] The basic characteristic aroma components of oolong tea include linalool, linalool oxides, cis-jasmone, jasmolactone, methyl jasmonate, benzyl alcohol, nerolidol, etc. Different oolong teas produce different volatile components due to different tea-making varieties, processing techniques, and fermentation degrees. These volatile components are combined in different proportions and contents, with some playing a leading role and some playing a promoting role, and they are coordinated with each other and perceived by the olfactory organ, forming the unique aromas and fragrance types of different kinds of oolong teas.
[0004] Oolong tea is a tea category with distinct Chinese characteristics and one of the six major tea categories in China. It is generally processed from large leaf tea and soft large leaf raw materials, with great geographical restrictions. It is mainly produced in the three provinces of Fujian, Guangdong and Taiwan, and there is also a small amount of production in provinces such as Hunan. The products mainly include Fujian oolong tea (divided into northern Fujian oolong tea and southern Fujian oolong tea), Guangdong single clump tea and Taiwan oolong tea, etc. For the tea raw materials of medium and small leaves, due to the thin cutin layer of the leaves, low mechanical strength of the cell wall, difficult regulation of oxidation products in the withering process, high loss rate of amino acids, high volatilization rate of aroma components, and the retention rate of finished product tea polyphenols being less than 70% of the traditional process, the medium and small leaf raw materials cannot meet the oolong tea quality standard (GB / T 30357.2-2013) during the processing process, so they are mostly limited to green tea processing. Summary of the Invention
[0005] The purpose of the present invention is to provide a method for preparing oolong tea based on medium and small leaf raw materials and the oolong tea, so as to solve the technical problem that medium and small leaf tea cannot be processed into oolong tea.
[0006] To achieve the above purpose, the present invention is implemented by adopting the following technical solutions: According to one aspect of the present invention, there is provided a method for preparing oolong tea based on medium and small leaf raw materials, including the following steps: Picking: Selecting fresh medium and small leaf tea with a size of 1.3 cm - 2.5 cm and a water content of 80% - 85%; Withering: Placing the tea leaves indoors for withering and dehydration to reduce the water content of the tea leaves to 65% - 75%; Withering: The tea leaves are subjected to a withering process once to make the appearance of the tea leaves meet the first appearance standard, and the water content is reduced to 45%-55%. Fixing: The tea leaves are processed at a temperature of 240℃-265℃ for 20min-25min to make the water content of the tea leaves 25%-35%. Air separation: The tea leaves are blown with cold air at a temperature of 15℃-18℃ to make the water content of the tea leaves 20%-28%. Moisture regain: The water content of the tea leaves is restored to 30%-35%. Rolling: The tea leaves are rolled to make the tea leaves in a state of strip-shaped and tightly locked with a slight bend, and the water content of the tea leaves is 30%-40%. Baking: After the tea leaves are scattered, they are baked at a temperature of 80℃-110℃ to make the water content of the tea leaves drop below 4%.
[0007] The freshly picked tea leaves are fresh leaves with one bud and one leaf or one bud and two leaves and a lot of white hairs; in the dry matter of the fresh tea leaves, the content of tea polyphenols is ≥28%, the content of amino acids is ≥4%, and the content of caffeine is 3%-4%.
[0008] The first appearance standard is: the overall color of the tea leaves is green with a brownish tint, the color of the edges of the tea leaves turns slightly red, and the area of red color change at the leaf edges reaches 35%-40%.
[0009] Furthermore, during air separation, the cold air speed is 3.5-5.5m / s.
[0010] Adopting the above technical solution enables the small and medium leaf species raw materials that originally did not meet the traditional oolong tea processing standards to produce oolong tea that meets the standards, which not only broadens the production areas of oolong tea raw materials, expands the application range of small and medium leaf species tea leaves, but also enriches the existing tea varieties.
[0011] Furthermore, before the withering step, there is also a spreading step, and the process conditions of the spreading step include: The tea leaves are spread out in the sun at 28±2℃, the spreading thickness is 5cm-6cm; the spreading time is 5min-8min, and the tea leaves are turned 3-5 times during this period.
[0012] According to an embodiment of the present invention, the process conditions of the withering step include: the tea leaves are spread out to a thickness of 8cm-12cm, the temperature is 20℃-25℃, and the withering time is 50min-70min; or, The technological conditions of the withering step include: spreading the tea leaves to a thickness of 5 cm - 8 cm, covering the surface with a wet cloth, withering time of 6 h - 7 h, during which the tea leaves are cooled with cold air every 45 min - 60 min, the cold air temperature is 18 °C - 20 °C, and the cold air wind speed is 3.5 - 5.5 m / s. The wet cloth is soaked in clean water before use, and when in use, the excess water is wrung out of the wet cloth so that the water absorption of the wet cloth is preferably 40% - 50%.
[0013] Adopting the above technical solution, the tea leaves are successively subjected to sun drying and spreading treatment and indoor withering treatment to form a compound withering process, which helps to form a gradient control of the water content of the tea leaves. During the spreading process, the water content of the tea leaves drops by about 5%, and during the indoor withering step, the water content of the tea leaves drops by about 10%. After the compound withering process, the water content of the tea leaves is 65% - 70%.
[0014] According to an embodiment of the present invention, in the making green step, the following steps are included: If the tea leaves reach the first appearance standard within the first shaking green time, stop making green; If the tea leaves do not reach the first appearance standard within the first shaking green time, make the tea leaves reach the first appearance standard through the spreading - shaking green process or the withering - shaking green process.
[0015] During a shaking green treatment process, the first shaking green time is 30 min, and the rotation speed is controlled at 18 rpm - 20 rpm.
[0016] According to an embodiment of the present invention, the spreading - shaking green process includes the following steps: Take out the tea leaves after the first shaking green and spread them in the sun at 28 ± 2 °C for no more than 30 min; then perform the second shaking green. During the second shaking green treatment process, the shaking green time is 18 min - 22 min, and the rotation speed is controlled at 22 rpm - 24 rpm; spread the tea leaves in the sun at 28 ± 2 °C again for no more than 30 min; according to the condition of the tea leaves, a third shaking green can also be set. During the third shaking green treatment process, the shaking green time is 13 min - 17 min, and the rotation speed is controlled at 26 rpm - 28 rpm. After the spreading - shaking green process, the water content of the tea leaves is reduced to 45% - 55%.
[0017] According to an embodiment of the present invention, the withering - shaking green process includes the following steps: The tea leaves after the first withering are placed indoors for withering, and the withering time is 45 min - 70 min. During this period, the tea leaves are cooled with cold air, the temperature of the cold air is 18°C - 20°C, and the wind speed of the cold air is 3.5 - 5.5 m / s; then the second withering is carried out. During the second withering process, the withering time is 18 min - 23 min, and the rotation speed is controlled at 22 rpm - 24 rpm; then the tea leaves are left standing for 30 min - 40 min, and the temperature is 18°C - 20°C; according to the condition of the tea leaves, a third withering can also be set. During the third withering process, the withering time is 13 min - 17 min, and the rotation speed is controlled at 26 rpm - 28 rpm. After the withering - withering process, the water content of the tea leaves is reduced to 45% - 55%.
[0018] According to an embodiment of the present invention, in the rolling step, manual rolling, machine rolling, or a combination of manual and machine rolling can be adopted.
[0019] In the rolling step, when manual rolling is adopted, the tea leaves are displaced back and forth, left and right, and gently shaken and stirred with a little pressure. The rolling force gradually increases from light to heavy until the juice overflows, and the rolling duration is 25 min - 30 min.
[0020] In the rolling step, when machine rolling is adopted, first, it is gently pressed and rolled for 15 min - 20 min, and then the pressure is increased by 30% for heavy rolling for 5 min - 8 min. Generally, when machine rolling is adopted, the rolling pressure is set at 0.5 MPa - 0.8 MPa, the temperature is 18°C - 20°C, and the humidity is 80% - 85% in the initial light rolling stage; in the subsequent heavy rolling stage, the rolling pressure is set at 1.2 MPa - 1.5 MPa, the temperature is 25°C - 28°C, and the humidity is 65% - 75%.
[0021] In the rolling step, when a combination of manual and machine rolling is adopted, first manual rolling is carried out, and then machine rolling is carried out, and the force during the rolling process gradually increases from light to heavy.
[0022] Adopting the method of segmented rolling and rolling the tea leaves with the force gradually increasing from light to heavy helps the tea leaves to take shape, making the obtained tea leaves in a "tightly locked and slightly curved" strip shape.
[0023] According to an embodiment of the present invention, in the baking step, a segmented baking process is adopted.
[0024] Preferably, the process conditions of the segmented baking are: first, bake at 100 - 110°C for 10 - 15 min; then bake at 85 - 95°C for 40 - 60 min.
[0025] Preferably, the process conditions for stepwise baking are as follows: first bake at 100 - 110°C for 10 - 15 minutes; then bake at 90 - 95°C for 40 - 50 minutes; then bake at 80 - 85°C for 20 - 30 minutes.
[0026] According to another aspect of the present invention, there is provided an oolong tea prepared by using any one of the above oolong tea preparation methods based on medium and small leaf tea varieties as raw materials; In the obtained oolong tea, the moisture content is not higher than 4%, the tea polyphenol content is 15% - 18%, the amino acid content is 2.2% - 2.8%, the caffeine content is 2% - 2.2%, the theaflavin content is 0.8% - 1.6%, and the jasmonolide content is ≥ 0.05%.
[0027] According to an embodiment of the present invention, in the picking step, Xinyang population variety alpine drought tea is selected.
[0028] Furthermore, in the picking step, among the selected tea raw materials, in the dry matter of fresh tea leaves, the tea polyphenol content is ≥ 28%, the amino acid content is ≥ 4%, and the caffeine content is 3% - 4%.
[0029] Compared with the prior art, the present invention has at least the following beneficial effects: 1. The present invention realizes a technological breakthrough in processing oolong tea using medium and small leaf tea varieties, enabling raw materials that originally did not meet the traditional oolong tea processing standards to produce oolong tea that meets the standards. This not only broadens the production areas of oolong tea raw materials, expands the application scope of medium and small leaf tea leaves, but also enriches the existing tea varieties.
[0030] 2. The present invention breaks through the limitation that the traditional oolong tea process flow needs to be carried out in sequence and each link is only once. The order of multiple links in the processing technology can be adjusted or some links can be deleted according to the actual situation. In this way, the adaptability of the tea-making process to weather changes and raw material states is improved, which helps to improve the uniformity of product quality.
[0031] 3. The tea obtained by the present invention shows a golden and bright color after brewing, with a certain density of oxygen bubbles visible on the surface, and an obvious oil layer suspended on the surface of the soup. It has a natural floral fragrance in terms of smell and a honey fragrance in terms of taste. Moreover, the color of the soup remains stable after multiple infusions, and the taste changes from honey fragrance to light fragrance.
[0032] 4. The present invention adds a winnowing step in the oolong tea processing technology, which can not only remove incomplete leaves and impurities in the tea, but also use slightly cooler cold air to cool the tea leaves after fixation, thereby reducing the loss of nutrients in the tea leaves and helping to enrich the taste of the obtained tea. BRIEF DESCRIPTION OF THE DRAWINGS
[0033] The accompanying drawings forming a part of this invention are used to provide a further understanding of the invention. The schematic embodiments and descriptions thereof of the invention are used to explain the invention and do not constitute an improper limitation of the invention. In the drawings: Figure 1 It is a photo of the dry tea appearance of the tea oolong tea obtained in Example 1; Figure 2 It is a photo of the appearance of the leaf bottom after brewing the oolong tea obtained in Example 1; Figure 3 It is a comparison photo of the leaf bottom after brewing the oolong tea obtained in Example 1 and the leaf bottom after brewing the Taiwan oolong tea; Figure 4 It is a comparison photo of the tea soup after brewing the oolong tea obtained in Example 1 twice and the tea soup after brewing the Taiwan oolong tea twice. Detailed implementation manners
[0034] The present invention will be described in detail below with reference to the drawings and in combination with embodiments. It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.
[0035] The following detailed descriptions are all exemplary descriptions, aiming to provide further detailed descriptions of the present invention. Unless otherwise specified, all technical terms adopted by the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs. The terms used in the present invention are only for describing specific implementation manners and are not intended to limit the exemplary embodiments according to the present invention.
[0036] Example 1 This example provides a method for preparing oolong tea based on medium and small leaf tea varieties, and the oolong tea obtained by using this method. The population variety of high mountain dry tea in Shihegang, Shihe District, the core production area of Xinyang Maojian is used as the raw material, and the picking time is from mid-April to early May; it includes the following steps: (1) Picking: Picking fresh tea leaves with one bud and one leaf or one bud and two leaves, the picking time is from April 15th to May 10th, and the average daily temperature is 18°C - 22°C; the tea leaf size is 1.3 cm - 1.5 cm, and the water content of the fresh tea leaves is 85% (detection method: GB5009.3 - 2016); in the dry matter of the fresh tea leaves, the content of tea polyphenols is 30% (detection method: GB / T 8313 - 2018), the content of amino acids is 4.5% (detection method: GB / T 8314 - 2013), and the content of caffeine is 3.6% (detection method: HPLC method).
[0037] (2) Spreading: Placing the picked tea leaves in the sun at 28 ± 1°C for spreading, the spreading thickness is 5 cm - 6 cm; the spreading time is 5 minutes, and the tea leaves are manually turned 3 times during this period.
[0038] (3) Withering: The tea leaves after spreading are placed indoors for withering and dehydration. The withering thickness is 8 cm - 12 cm, the temperature is 25°C, and the withering time is 50 min, so that the water content of the tea leaves drops to 68%. (4) Making green: The tea leaves after spreading are subjected to a first shaking treatment. If the first appearance standard is reached within the first shaking time, the process stops. The first shaking time is 30 min, and the first appearance standard is that the overall color of the tea leaves is green with a brownish tint, the color of the tea leaf edges turns slightly red, and the red - changed area at the leaf margins reaches 35% - 40%. If the tea leaves do not reach the first appearance standard within the first shaking time, the tea leaves are made to reach the first appearance standard through the process of spreading - shaking.
[0039] Specifically, in this embodiment, during the first shaking treatment, the rotation speed is controlled at 20 rpm. After the first shaking for 30 min, the temperature of the tea leaves rises by 3°C, but the tea leaves still do not reach the first appearance standard. The tea leaves are taken out and placed in sunlight at 28 ± 1°C for a second spreading, with a spreading time of 30 min. Then, a second shaking is carried out, with a shaking time of 22 min and the rotation speed controlled at 22 rpm. After the second shaking treatment, the temperature of the tea leaves rises by 6°C, and the water content drops to 60%, but the tea leaves still do not reach the first appearance standard. The tea leaves are placed in sunlight at 28 ± 1°C again for spreading, with a spreading time of 20 min. At this time, the water content of the tea leaves drops to 55%, and the appearance reaches the first appearance standard. During the spreading - shaking process, the water loss of the tea leaves is 13%. This step can release the tea polyphenols in the tea leaves and at the same time raise the temperature of the tea leaves.
[0040] Through the alternating process of three - time shaking and spreading, the tea leaves lose water in a gradient manner during this process, which helps to precisely control the oxidation degree and fermentation focus of the tea leaves.
[0041] (5) Fixing: The tea leaves after making green are subjected to high - temperature frying treatment at 265°C for 20 min, so that the water content of the tea leaves is reduced to 35%. Adopting high - temperature short - time fixing helps to balance the inactivation of enzyme activity and the retention of nutrients in the tea leaves, enriching the taste of the obtained tea leaves.
[0042] (6) Air - sorting: Cold air with a wind speed of 5.5 m / s and a temperature of 15°C is used to blow the tea leaves, blowing out the incomplete leaves and impurities, and using the cold air to cool the tea leaves so that the water content of the tea leaves is 20%.
[0043] (7) Conditioning: The tea leaves after air - sorting are placed in a moist cotton bag for conditioning for 2 h, so that the water content of the tea leaves is restored to 30%. The cotton bag is fully soaked in clean water before use, and when in use, the excess water is wrung out from the cotton bag. The water absorption of the cotton bag is 40%.
[0044] (8) Rolling: A method of combining manual and machine rolling is adopted to make the juice in the tea leaves overflow.
[0045] Specifically, the tea leaves still placed in a moist cotton bag after rewetting, together with the cotton bag, are gently kneaded by hand, causing the tea leaves to shift in all directions, and slightly pressed, shaken, and turned. The kneading intensity gradually increases from light to heavy until juice overflows. The specific kneading method and intensity can be adjusted according to the experience of the tea maker. The kneading duration is 20 minutes. Then, the tea leaves are transferred to a machine. First, set the kneading pressure to 0.6 MPa, the temperature to 20 °C, and the humidity to 80%, and perform light pressure and light kneading for 20 minutes. Then, set the kneading pressure to 1.2 MPa, the temperature to 25 °C, the humidity to 70%, and the time to 15 minutes, so that the water content of the tea leaves is 40%. After kneading, the tea leaves reach a state where they can be slightly held in a fist when held in the palm, and can be loosened when flattened, with a tightly locked and slightly curved shape. This step reduces the fermentation degree by about 15 - 20%.
[0046] (9) Baking: After the tea leaves are scattered, they are evenly spread to a thickness of 3 cm - 4 cm, placed in a baking oven, and baked in segments until the water content of the dried tea is reduced to 2% to obtain dried oolong tea. Specifically, the process conditions for segmental baking are: first bake at 100 °C for 10 minutes, and then bake at 90 °C for 60 minutes.
[0047] The dried tea leaves obtained by the above method are tightly knotted and slightly curved, with white hairs visible. Among them, the water content is ≤3%, the tea polyphenol content is 18%, the amino acid content is 2.2%, the caffeine content is 2.0%, the theaflavin content is 0.8% (detection method: HPLC method), the nerolidol content is 0.7% (detection method: GC - MS method), the linalool oxide content is 0.2% (detection method: GB 29979—2013), and the jasmonolide content is 0.06% (detection method: GC - MS method). In the dried tea of traditional oolong tea, the water content does not exceed 5%, the tea polyphenol content is 10% - 18%, the amino acid content is 1% - 2%, the caffeine content is 2% - 3%, the nerolidol content is 0.1% - 0.3%, the linalool oxide content is 0.05% - 0.2%, and the jasmonolide content is 0.01% - 0.05%. It can be seen that the tea leaves obtained by the method of this embodiment meet the evaluation standards of oolong tea.
[0048] Moreover, the tea soup brewed from the dried oolong tea obtained by the method of this embodiment can present various floral and fruity honey - like aromas. The taste is sweet, fresh, and refreshing, the soup color is golden and bright (chromaticity value Y = 85 - 90, X = 0.35 - 0.38), and the bottom leaves are overall brownish - yellow, red, and green, with no obvious distinction in the color of the leaf edges. The appearance of the dried tea of the oolong tea obtained in this embodiment is shown in Figure 1 ; the appearance of the bottom leaves after brewing is shown in Figure 2 ; the comparison diagram of the bottom leaves after brewing of the oolong tea obtained in this embodiment and the bottom leaves after brewing of Taiwan oolong tea is shown in Figure 3, the tea obtained in this embodiment is on the left side of the figure, and the Taiwan oolong tea is on the right side; for the comparison chart of the tea soup after brewing the oolong tea obtained in this embodiment twice and the Taiwan oolong tea after brewing twice, see Figure 4 , the tea obtained in this embodiment is on the left side of the figure, and the Taiwan oolong tea is on the right side. The duration of the floral honey fragrance after brewing the oolong tea obtained in this embodiment is ≥5 infusions, and the content of jasmonolide in the tea soup detected by the GC-MS method is ≥0.03% after 5 infusions.
[0049] Example 2 This embodiment provides a method for preparing oolong tea based on medium and small leaf tea varieties, using the population variety high mountain drought tea in Shihegang, Shihe District, the core production area of Xinyang Maojian. The differences from Example 1 are as follows: During the picking process in step (1), the water content of the fresh tea leaves is 84%; among the dry matter of the fresh tea leaves, the content of tea polyphenols is 28%, the content of amino acids is 5%, and the content of caffeine is 3.4%.
[0050] During the withering process in step (2), the withering time is 8 min, and the tea leaves are turned 5 times during this period.
[0051] During the withering process in step (3), the temperature is 20 °C and the withering time is 70 min; the water content of the tea leaves is reduced to 65%.
[0052] During the green-making process in step (4), during a single rocking treatment process, the rotation speed is controlled at 18 rpm. After a single rocking for 30 min, the temperature of the tea leaves rises by 4 °C, but the tea leaves still do not reach the first appearance standard. The tea leaves are taken out and placed in the sun at 28 ± 1 °C for a second withering, and the withering time is 25 min; then a second rocking is carried out, the rocking time is 18 min, and the rotation speed is controlled at 24 rpm. After the second rocking treatment, the temperature of the tea leaves rises by 6 °C, and the water content is reduced to 60%, but the tea leaves still do not reach the first appearance standard. The tea leaves are placed in the sun at 28 ± 1 °C for withering again, and the withering time is 30 min; at this time, the appearance of the tea leaves still does not reach the first appearance standard, and then a third rocking is carried out, the rocking time is 15 min, and the rotation speed is controlled at 26 rpm. After the third rocking treatment, the temperature of the tea leaves rises by 8 °C, and the water content is reduced to 45%. This step can release the tea polyphenols in the tea leaves and at the same time raise the temperature of the tea leaves.
[0053] During the fixing process in step (5), the tea leaves after green-making are subjected to high-temperature frying treatment at a temperature of 245 °C for 25 min to reduce the water content of the tea leaves to 25%.
[0054] During the winnowing process in step (6), cold air with a wind speed of 4.5 m / s and a temperature of 18 °C is used to blow the tea leaves, blowing out the incomplete leaves and impurities, and using the cold air to cool the tea leaves so that the water content of the tea leaves is 26%.
[0055] In the step (7) of rehydration, the tea leaves after winnowing are placed in a damp cotton bag for rehydration for 3 hours to restore the water content of the tea leaves to 35%. The cotton bag is fully soaked in clean water before use. When in use, the excess water in the cotton bag is wrung out, and the water absorption of the cotton bag is 50%.
[0056] In the step (8) of rolling, mechanical rolling is adopted. The tea leaves are transferred into the machine. First, the rolling pressure is set at 0.8 MPa, the temperature is 18 °C, and the humidity is 85%, and light pressure and light rolling are carried out for 15 minutes. Then, the rolling pressure is set at 1.5 MPa, the temperature is 28 °C, the humidity is 75%, and the time is 10 minutes, so that the water content of the tea leaves is 30%. After rolling, the tea leaves reach the state where they can be slightly held together in a ball by gently clenching the palm, can be loosened when flattened, and the strip shape is tightly locked and slightly curved.
[0057] In the step (9) of baking, the segmented baking is divided into three sections: initial baking, medium baking, and fine baking. The specific process conditions are as follows: Initial baking: Bake at 110 °C for 10 minutes. In this process, the water content of the tea leaves drops from 30% to 15%. Medium baking: Bake at 90 °C for 50 minutes. In this process, the water content of the tea leaves drops from 15% to 8%. Fine baking: Bake at 80 °C for 30 minutes. In this process, the water content of the tea leaves drops from 8% to 2.8%.
[0058] Other steps and conditions are the same.
[0059] The water content of the dry tea obtained by the method of this embodiment is 2.8%, the tea polyphenol content is 17.2%, the amino acid content is 2.4%, the caffeine content is 2.1%, the theaflavin content is 1.1%, the nerolidol content is 1%, the linalool oxide content is 0.15%, and the jasminolide content is 0.05%, meeting the evaluation standards of oolong tea.
[0060] Example 3 This embodiment provides a method for preparing oolong tea based on medium and small leaf tea varieties. Using the population variety of high mountain dry tea in Shihegang, Shihe District, the core production area of Xinyang Maojian as raw materials, the differences from Example 1 are as follows: In the step (1) of picking, the water content of the fresh tea leaves is 85%; in the dry matter of the fresh tea leaves, the tea polyphenol content is 29%, the amino acid content is 5%, and the caffeine content is 3.8%.
[0061] In the step (2) of spreading, the spreading time is 6 minutes, and the tea leaves are turned 4 times during this period.
[0062] In the step (3) of withering, the temperature is 22 °C, and the withering time is 60 minutes; the water content of the tea leaves is reduced to 65%.
[0063] During the withering process in step (4), during the first withering treatment, the rotation speed is controlled at 19 rpm. After the first withering for 30 minutes, the temperature of the tea leaves rises by 3 °C, but the tea leaves still do not reach the first appearance standard. The tea leaves are taken out and placed in sunlight at 28 ± 1 °C for the second spreading, with a spreading time of 20 minutes; then, the second withering is carried out, with a withering time of 20 minutes and the rotation speed controlled at 23 rpm. After the second withering treatment, the temperature of the tea leaves rises by 7 °C and the moisture content drops to 62%, but the tea leaves still do not reach the first appearance standard. The tea leaves are placed in sunlight at 28 ± 1 °C for spreading again, with a spreading time of 25 minutes; at this time, the appearance of the tea leaves still does not reach the first appearance standard, and then the third withering is carried out, with a withering time of 15 minutes and the rotation speed controlled at 28 rpm. After the third withering treatment, the temperature of the tea leaves rises by 10 °C and the moisture content drops to 50%. This step can release the tea polyphenols in the tea leaves and at the same time raise the temperature of the tea leaves.
[0064] During the fixation process in step (5), the withered tea leaves are subjected to high-temperature frying treatment at a temperature of 250 °C for 22 minutes to reduce the moisture content of the tea leaves to 30%.
[0065] During the winnowing process in step (6), cold air with a wind speed of 4.5 m / s and a temperature of 16 °C is used to blow the tea leaves, blowing out the incomplete leaves and impurities, and using the cold air to cool the tea leaves so that the moisture content of the tea leaves is 24%.
[0066] During the softening process in step (7), the winnowed tea leaves are placed in a damp cotton bag for softening for 2.5 hours to restore the moisture content of the tea leaves to 32%. The cotton bag is fully soaked in clean water before use, and when in use, the excess water is wrung out from the cotton bag. The water absorption of the cotton bag is 45%.
[0067] During the rolling process in step (8), mechanical rolling is adopted. The tea leaves are transferred to the machine. First, the rolling pressure is set at 0.6 MPa, the temperature is 18 °C, and the humidity is 85%, and light pressure and light rolling are carried out for 15 minutes; then, the rolling pressure is set at 1.2 MPa, the temperature is 28 °C, and the humidity is 75%, for 10 minutes, so that the moisture content of the tea leaves is 30%. After rolling, the tea leaves reach the state where they can be slightly held together in the palm of the hand, can be loosened when flattened, and the strip is tightly locked and slightly curved.
[0068] During the baking process in step (9), the segmented baking is divided into three stages: initial baking, medium baking, and fine baking. The specific process conditions are as follows: Initial baking: Bake at 100 °C for 15 minutes. During this process, the moisture content of the tea leaves drops from 30% to 17%; Medium baking: Bake at 95 °C for 45 minutes. During this process, the moisture content of the tea leaves drops from 17% to 7%; Precise roasting: Roast at 85°C for 20 minutes. During this process, the water content of the tea leaves drops from 7% to 3%.
[0069] All other steps and conditions are the same.
[0070] The water content of the dry tea leaves obtained by the method of this example is 3%, the tea polyphenol content is 17.5%, the amino acid content is 2.5%, the caffeine content is 2.0%, the theaflavin content is 1.5%, the nerolidol content is 0.8%, the linalool oxide content is 0.18%, and the jasmin lactone content is 0.06%, meeting the evaluation standards of oolong tea.
[0071] Example 4 This example provides a method for preparing oolong tea based on medium and small leaf tea varieties. Using the group variety high mountain dry tea in Shihegang, Shihe District, the core production area of Xinyang Maojian, as raw materials, it includes the following steps: (1) Picking: Pick fresh tea leaves with one bud and one leaf or one bud and two leaves. The picking date is from late May to mid-June, and the picking time is in the afternoon, with an average daily temperature of 25°C - 28°C; the tea leaf size is 1.5 cm - 2.5 cm, and the water content of the fresh tea leaves is 84%; in the dry matter of the fresh tea leaves, the tea polyphenol content is 25%, the amino acid content is 5.5%, and the caffeine content is 3.6%.
[0072] (2) Withering: Place the tea leaves indoors and spread them to a thickness of 5 cm - 8 cm, cover the surface with a wet cloth, wither for 6 hours, and during this period, cool the tea leaves with cold air for 15 minutes every 1 hour. The cold air wind speed is 3.5 m / s, and the temperature is 20°C. After withering, the water content of the tea leaves is 75%. The wet cloth is soaked in clean water before use, and when in use, wring out the excess water from the wet cloth so that the water absorption of the wet cloth is preferably 40% - 50%.
[0073] (3) Making green: Perform a shaking green treatment on the withered tea leaves for 20 minutes to reduce the water content of the tea leaves to 65%. After the tea leaf temperature rises by 3°C - 5°C, check the tea leaf state. If the tea leaves meet the first appearance standard, stop shaking green. If the tea leaves do not meet the first appearance standard, pass through the withering - shaking green process to make the tea leaves meet the first appearance standard.
[0074] Specifically, in this embodiment, after the first withering and rolling, the tea leaves do not reach the first appearance standard. The tea leaves are placed indoors for withering for 45 minutes. During this period, cold air is used to cool the tea leaves to release the green gas. The moisture content of the tea leaves is reduced to about 58%. The cold air speed is 3.5 m / s and the temperature is 20°C. Then, the tea leaves after the second withering are subjected to the second withering and rolling for 18 minutes to make the moisture content of the tea leaves 50%. At this time, the color of the tea leaves deepens and shows a mixed color of green, brown, and red. Then, the tea leaves after the second withering and rolling are taken out and left standing for 40 minutes. At this time, the moisture content of the tea leaves is 45%, there is no green gas, there is a floral fragrance, and it meets the first appearance standard.
[0075] (4) Fixing: The tea leaves after the making process are stir-fried at a high temperature of 240°C for 25 minutes to reduce the moisture content of the tea leaves to 30%.
[0076] (5) Air separation: Cold air with a speed of 3.5 m / s and a temperature of 18°C is used to blow the tea leaves to blow out the incomplete leaves and impurities, and the cold air is used to cool the tea leaves to make the moisture content of the tea leaves 28%.
[0077] (6) Moisture regain: The tea leaves after air separation are placed in a damp cotton bag for moisture regain for 3 hours to restore the moisture content of the tea leaves to 35%. The cotton bag is fully soaked in clean water before use. When in use, the excess water in the cotton bag is wrung out, and the water absorption of the cotton bag is 50%.
[0078] (7) Rolling: In the way of manual rolling, the tea leaves still placed in the damp cotton bag after moisture regain are gently rolled by hand together with the cotton bag to make the tea leaves change positions in all directions, and slightly pressed and shaken and dialed. The rolling strength gradually increases from light to heavy until the juice overflows. The rolling duration is 30 minutes.
[0079] (8) After the tea leaves are scattered, they are evenly spread to a thickness of 3 cm - 4 cm and put into a baking box. Baking is carried out in a constant temperature manner to obtain oolong tea dry tea. The technological conditions for baking are: the temperature is 100°C, and it is dried in two times. The baking time for both times is 10 minutes. The moisture content of the obtained dry tea is 3%.
[0080] The moisture content of the tea dry tea obtained by the above method is 3%, the tea polyphenol content is 15%, the amino acid content is 2.8%, the caffeine content is 2.2%, the theaflavin content is 1.5%, the nerolidol content is 1%, the linalool oxide content is 0.08%, and the jasmonolide content is 0.05%; it meets the evaluation standards of oolong tea. The tea soup brewed from the oolong tea dry tea obtained by the method of this embodiment can present various fragrance types such as honey fragrance and fruit honey fragrance, the taste is sweet, fresh and refreshing, the soup color is golden and bright, the bottom of the leaves is overall brown, yellow, red and green, and there is no obvious distinction in the color of the leaf edges.
[0081] Example 5 This embodiment provides a method for preparing oolong tea based on small and medium leaf tea varieties. The raw material used is the population variety of high mountain dry tea in Shihegang, Shihe District, the core production area of Xinyang Maojian. The difference from Example 4 is as follows: During the picking process in step (1), the picking date is from September to October, the picking time is in the afternoon, and the average daily temperature is 25°C - 28°C; the water content of the fresh tea leaves is 80%; in the dry matter of the fresh tea leaves, the content of tea polyphenols is 28%, the content of amino acids is 5%, and the content of caffeine is 4%.
[0082] During the withering process in step (2), the withering time is 7 hours. During this period, the tea leaves are cooled for 10 minutes every 45 minutes using cold air. The cold air wind speed is 4 m / s, and the temperature is 18°C. After the withering ends, the water content of the tea leaves is 72%.
[0083] During the making green process in step (3), the withered tea leaves are subjected to a first shaking green treatment for 20 minutes to reduce the water content of the tea leaves to 65%. For the tea leaves that do not meet the first appearance standard, the tea leaves are placed indoors for withering again for 60 minutes. During this period, the tea leaves are cooled using cold air to release the green smell, and the water content of the tea leaves is reduced to about 60%. The cold air wind speed is 4 m / s, and the temperature is 18°C. Then, the tea leaves after the second withering are subjected to a second shaking green for 23 minutes to make the water content of the tea leaves 55%; at this time, the color of the tea leaves deepens, showing a mixed color of green, brown, and red. Then, the tea leaves after the second shaking green are taken out and left to stand for 30 minutes. At this time, the water content of the tea leaves is 50%, there is no green smell, there is a floral fragrance, and it meets the first appearance standard.
[0084] During the fixation process in step (4), the made green tea leaves are subjected to high-temperature frying treatment at a temperature of 240°C for 20 minutes to reduce the water content of the tea leaves to 31%.
[0085] During the winnowing process in step (5), the tea leaves are blown with cold air at a wind speed of 5 m / s and a temperature of 17°C to blow out the incomplete leaves and impurities, and the cold air is used to cool the tea leaves to make the water content of the tea leaves 25%.
[0086] During the rehydration process in step (6), the winnowed tea leaves are placed in a damp cotton bag for rehydration for 2 hours to restore the water content of the tea leaves to 32%. The cotton bag is fully soaked in clean water before use, and when in use, the excess water is wrung out from the cotton bag. The water absorption of the cotton bag is 40%.
[0087] In the rolling process of step (7), mechanical rolling is adopted. Transfer the tea leaves into the machine. First, set the rolling pressure to 0.5 MPa, the temperature to 18 °C, and the humidity to 85%, and perform light pressure and light rolling for 15 minutes. Then, set the rolling pressure to 1.2 MPa, the temperature to 25 °C, the humidity to 70%, and the time to 10 minutes, so that the water content of the tea leaves is 40%. After rolling, the tea leaves reach a state where they can be slightly held in a ball in the palm, can be loosened when flattened, and the strip is tightly locked and slightly curved.
[0088] All other steps and conditions are the same.
[0089] The water content in the dry tea of the tea leaves obtained by the above method is 3%, the tea polyphenol content is 16%, the amino acid content is 2.7%, the caffeine content is 2.1%, the theaflavin content is 1.6%, the nerolidol content is 1.1%, the linalool oxide content is 0.10%, and the jasmin lactone content is 0.05%; it meets the evaluation standards of oolong tea. The tea soup brewed from the dry oolong tea obtained by the method of this example can present various fragrance types such as floral honey fragrance and fruit honey fragrance, the taste is sweet, fresh and refreshing, the soup color is golden and bright, the bottom of the leaves is overall brownish-yellow, red and green, and there is no obvious distinction in the color of the leaf edges.
[0090] Example 6 This example provides a method for preparing oolong tea based on medium and small leaf tea varieties. Using the group variety high mountain dry tea in Shihegang, Shihe District, the core production area of Xinyang Maojian as the raw material, the differences from Example 4 are as follows: In the picking process of step (1), the picking date is from late April to early May, and the picking time is in the afternoon; the water content of the fresh tea leaves is 83%; in the dry matter of the fresh tea leaves, the tea polyphenol content is 30%, the amino acid content is 4%, and the caffeine content is 3.8%.
[0091] In the withering process of step (2), the withering time is 6 hours. During this period, the tea leaves are cooled for 15 minutes every 50 minutes with cold air. The cold air speed is 5.5 m / s and the temperature is 18 °C. After withering, the water content of the tea leaves is 70%.
[0092] In the green-making process of step (3), after the first shaking, the tea leaves do not reach the first appearance standard. Place the tea leaves in indoor withering for 60 minutes. During this period, the tea leaves are cooled with cold air to release the green gas. The water content of the tea leaves drops to about 58%. The cold air speed is 5.5 m / s and the temperature is 18 °C. Then, perform the second shaking on the tea leaves after the second withering for 25 minutes to make the water content of the tea leaves 58%; at this time, the color of the tea leaves deepens and shows a mixed color of green, brown and red. Then, take out the tea leaves after the second shaking and let them stand for 30 minutes. At this time, the water content of the tea leaves is 55%, there is no green gas, there is a floral fragrance, and it meets the first appearance standard.
[0093] In the step (4) of fixing, the tea leaves after withering are stir-fried at a high temperature of 240°C for 20 minutes, so that the water content of the tea leaves is reduced to 35%.
[0094] In the step (5) of winnowing, cold air with a wind speed of 5.5 m / s and a temperature of 17°C is used to blow the tea leaves, blowing out the incomplete leaves and impurities, and using the cold air to cool the tea leaves so that the water content of the tea leaves is 28%.
[0095] In the step (6) of softening, the winnowed tea leaves are placed in a damp cotton bag for softening for 2 hours, so that the water content of the tea leaves is restored to 30%. The cotton bag is fully soaked in clean water before use, and when in use, the excess water in the cotton bag is wrung out. The water absorption of the cotton bag is 40%.
[0096] In the step (7) of rolling, mechanical rolling is adopted. The tea leaves are transferred into the machine. First, the rolling pressure is set to 0.6 MPa, the temperature is 18°C, and the humidity is 85%, and light pressure and light rolling are carried out for 15 minutes; then, the rolling pressure is set to 1.2 MPa, the temperature is 25°C, and the humidity is 72%, for 10 minutes, so that the water content of the tea leaves is 40%. After rolling, the tea leaves reach a state where they can be slightly held in a ball in the palm, can be loosened when flattened, and the strip shape is tightly locked and slightly curved.
[0097] Other steps and conditions are the same.
[0098] The water content of the dry tea of the tea leaves obtained by the above method is 3%, the tea polyphenol content is 16%, the amino acid content is 2.3%, the caffeine content is 2.2%, the theaflavin content is 1.2%, the nerolidol content is 0.8%, the linalool oxide content is 0.08%, and the jasmonolide content is 0.05%; it meets the evaluation standards of oolong tea. The tea soup brewed from the dry oolong tea obtained by the method of this embodiment can present various fragrance types such as floral honey fragrance and fruit honey fragrance, the taste is sweet, fresh and refreshing, the soup color is golden and bright, and the bottom of the leaves is overall brownish-yellow, red and green, and there is no obvious distinction in the color of the leaf edges.
[0099] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications or equivalent replacements can still be made to the specific embodiments of the present invention, and any modifications or equivalent replacements without departing from the spirit and scope of the present invention shall be covered by the protection scope of the claims of the present invention.
Claims
1. A method for preparing oolong tea based on raw materials of medium and small leaf tea varieties, characterized in that, It includes the following steps: Picking: Screening fresh tea leaves of medium and small leaf varieties with a size of 1.3 cm - 2.5 cm and a water content of 80% - 85%; Withering: Placing the tea leaves indoors for withering and dehydration to reduce the water content of the tea leaves to 65% - 75%; Green-making: Conducting a single shaking process on the tea leaves to make the appearance of the tea leaves meet the first appearance standard; Fixing: Treating the tea leaves at a temperature of 240°C - 265°C for 20 min - 25 min; Air separation: Blowing cold air with a temperature of 15°C - 18°C on the tea leaves to reduce the water content of the tea leaves to 20% - 28%; Moisture recovery: Restoring the water content of the tea leaves to 30% - 35%; Rolling: Rolling the tea leaves to make the tea leaves in a state of strip-shaped and tightly locked with a slight bend, and the water content of the tea leaves is 30% - 40%; Baking: After the tea leaves are scattered, baking them at a temperature of e80°C - 110°C to reduce the water content of the tea leaves to less than 4%; 2. The method for preparing oolong tea based on medium and small leaf variety raw materials according to claim 1, characterized in that, Before the withering step, it further includes a spreading step, and the process conditions of the spreading step include: Placing the tea leaves in the sun at 28 ± 2°C for spreading, with a spreading thickness of 5 cm - 6 cm; the spreading time is 5 min - 8 min.
3. The method for preparing oolong tea based on medium and small leaf variety raw materials according to claim 1, characterized in that, The process conditions of the withering step include: spreading the tea leaves to a thickness of 8 cm - 12 cm, at a temperature of 20°C - 25°C, and the withering time is 50 min - 70 min; or, The process conditions of the withering step include: spreading the tea leaves to a thickness of 5 cm - 8 cm, covering the surface with a wet cloth, and the withering time is 6 h - 7 h. During this period, the tea leaves are cooled with cold air every 45 min - 60 min, the cold air temperature is 18°C - 20°C, and the cold air wind speed is 3.5 - 5.5 m / s.
4. The method for preparing oolong tea based on medium and small leaf variety raw materials according to claim 1, characterized in that, In the green-making step, it includes the following steps: If the tea leaves reach the first appearance standard within the first shaking time, stop green-making; If the tea leaves do not reach the first appearance standard within the first shaking time, make the tea leaves reach the first appearance standard through the spreading - shaking process or the withering - shaking process; The first shaking time is 30 min.
5. The method for preparing oolong tea based on medium and small leaf variety raw materials according to claim 4, characterized in that, The spreading - shaking process includes the following steps: Taking out the tea leaves and placing them in the sun for spreading, with the spreading time not exceeding 30 min; then conducting a second shaking, with the shaking time of 18 min - 23 min; placing the tea leaves in the sun at 28 ± 2°C for spreading again; after the spreading - shaking process, the water content of the tea leaves drops to 45% - 55%.
6. The method for preparing oolong tea based on medium and small leaf variety raw materials according to claim 4, characterized in that, The withering - shaking process includes the following steps: Place the tea leaves indoors for withering for 45 min - 70 min. During this period, cool the tea leaves with cold air. The temperature of the cold air is 18°C - 20°C, and the wind speed of the cold air is 3.5 - 5.5 m / s. Then, perform shaking again to reduce the water content of the tea leaves to 45% - 55%. Next, let the tea leaves stand for 30 min - 40 min.
7. The method for preparing oolong tea based on medium and small leaf tea varieties according to claim 1, characterized in that In the rolling step, manual rolling, machine rolling, or a combination of manual and machine rolling can be used.
8. An oolong tea, characterized in that, Prepared by using the method for preparing oolong tea based on medium and small leaf tea varieties according to any one of claims 1 - 7; In the oolong tea, the water content is not higher than 4%, the tea polyphenol content is 15% - 18%, the amino acid content is 2.2% - 2.8%, the caffeine content is 2% - 2.2%, and the theaflavin content is 0.8% - 1.6%.
9. The oolong tea according to claim 8, characterized in that In the picking step, in the dry matter of the fresh tea leaves, the tea polyphenol content ≥ 28%, the amino acid content ≥ 4%, and the caffeine content is 3% - 4%.
10. The oolong tea according to claim 8, characterized in that In the picking step, select the Xinyang population variety of alpine dry tea.