Preparation process of dendrobium officinale black tea

Abstract

The invention discloses a dendrobium officinale black tea making process, which comprises the steps of raw material pretreatment, withering, rolling, fermentation, micro drying, full drying, natural annealing and the like, a plant extract can be used in the early stage of fermentation, and purified water is used in the later stage of fermentation. The plant extracting solution is rich in various aroma components and flavor substances, and the aroma and flavor can be effectively transferred into the tea leaves by using the extracting solution in the early stage of fermentation, so that the aroma and taste of the tea leaves are enhanced. Besides, the tea leaves are properly treated before fermentation, such as drying and rolling, so that the absorption capacity of the tea leaves to aroma components can be improved, the formation of some volatile aroma components in the tea leaves can be promoted through low-temperature drying, the aroma of the tea leaves is richer and more lasting, the content of bitter and astringent components in the tea leaves can be reduced, and the taste of the tea leaves is improved. The taste of the tea leaves is softer and more sweet, and meanwhile, the loss of soluble substances in the tea leaves is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of tea making technology, and in particular to a making process of dendrobium officinale black tea. Background Art

[0002] Dendrobium officinale leaves are the leaves of the Dendrobium officinale, which are rich in nutrients and active ingredients such as dendrobium polysaccharides, amino acids, and dendrobium alkaloids. They have the effects of clearing heat, relieving depression, anti-oxidation, nourishing the stomach, protecting the liver, lowering blood sugar and blood pressure. Dendrobium leaves have a wide range of uses. They can be used as both medicine and food. In folk culture, dendrobium leaves can be squeezed into juice, cooked, and dried to make tea. Dendrobium officinale black tea combines the medicinal value of Dendrobium officinale with the tea fragrance of black tea, and has many health benefits.

[0003] In the prior art, the production of Dendrobium officinale black tea mostly uses black tea and Dendrobium officinale stems to produce separately, and then the dry products of the two are mixed and blended in a certain proportion to obtain Dendrobium officinale black tea, or directly uses the leaves on the stems of Dendrobium officinale to make similar tea according to the black tea making process. In the Dendrobium officinale black tea made by this technical means, the nutrients of Dendrobium officinale and black tea cannot be fully integrated, and the complexed product of the two cannot be obtained. Moreover, when rolling, the material clumps seriously, and the complexation of the two contents is incomplete, resulting in less theaflavins and thearubigins in the tea soup, and the health effects of the Dendrobium components and tea components cannot be well exerted.

[0004] Therefore, it is necessary to provide a process for preparing Dendrobium Officinale Black Tea, so as to enhance the aroma and taste of the tea leaves and enable the nutritional components of Dendrobium Officinale and the nutritional components of black tea to be fully integrated with each other. Summary of the invention

[0005] The invention aims to provide a process for making Dendrobium officinale black tea, so as to solve the problems of poor aroma and taste, poor fusion effect of nutrient components, long fermentation time and insufficient mellow aroma in the existing black tea making process.

[0006] In order to solve the above technical problems, the present invention specifically provides the following technical solutions: The present invention provides a process for making Dendrobium officinale black tea, comprising the following steps: S1. Raw material pretreatment: Wash and dry the Dendrobium officinale leaves and mix them with fresh tea leaves in a weight ratio of 3:7, spread them evenly in a thickness of no more than 3 cm, and then leave them at night for 8h-10h; S2. Withering: Spread the tea leaves thinly and air-dry them in the soft sunlight before 10:00 or after 16:00 for about 1-2 hours. The thickness of the thin spread should be 1-3 cm. Turn the leaves over every 15 minutes to obtain the withered A-grade tea leaves. S3, rolling: putting the A-grade tea leaves into the rolling barrel of the rolling machine, and rolling the A-grade tea leaves for at least 30 minutes in the order of light rolling 1-heavy rolling 1-light rolling 2-heavy rolling 2-light rolling 3, until the rolled leaves are partially red or light yellow-green, and then breaking up the blocks and shaking them apart to obtain rolled B-grade tea leaves; S4, fermentation: the tea leaves of grade B are placed in an open container, the top of the container is covered with cotton cloth to cover the tea leaves of grade B, the cotton cloth is soaked with plant extract, and the tea leaves of grade B slowly turn red over 8-12 hours, during which the cotton cloth is re-soaked every 1 hour; S5, light drying: In S4, at the initial fermentation stage of the B tea leaves, the tea leaves are dried at a temperature of 40-60° C. for 1-2 hours and then continued to ferment to obtain the fermented C tea leaves; S6, full drying: 500g of C-grade tea leaves are placed in a baking drying oven, covered with dry cotton cloth, and baked twice, firstly with high heat for a short time of 2-3min, the temperature of which is controlled at 200-250°C, to obtain D-grade tea leaves; the D-grade tea leaves are spread in a ventilated and cool place for 30-60min, and then with low heat for a long time of 2-3h until fully dry, the temperature of which is controlled at 100-150°C, to obtain E-grade tea leaves; S8. Natural annealing: Put product E into a cotton bag while it is still hot, place it in a cool, dark and dry place for at least one month, and then naturally transform and anneal to obtain the finished tea product.

[0007] Preferably, in S3, the time of light kneading 1 is 12-15 minutes, and the upper cover of the kneading barrel just touches the tea leaves; the time of heavy kneading 1 is 5-8 minutes, and the upper cover of the kneading barrel is pressed down until it touches the tea leaves and then pressed down by 3-5 cm; the time of light kneading 2 is 3-6 minutes, and the upper cover of the kneading barrel returns to the top of the kneading barrel; the time of heavy kneading 2 is 8-10 minutes, and the upper cover of the kneading barrel is pressed down until it touches the tea leaves and then pressed down by 3-5 cm; the time of light kneading 3 is 2-5 minutes, and the upper cover of the kneading barrel returns to the top of the kneading barrel, and after kneading, the tea blocks are deblocked and shaken to obtain Grade B tea leaves.

[0008] Preferably, in S4, the bottom and top of the container are respectively covered with soaked cotton cloth to wrap the B-grade tea leaves, a pit is left in the middle of the pile of B-grade tea leaves, the bottom layer of cotton cloth can be seen in the pit, and the two layers of cotton cloth are in contact.

[0009] Preferably, in S4, the plant extract is a black tea extract, and the preparation steps of the black tea extract are as follows: (1) Tea leaves crushing: crushing the fresh leaves of black tea tree; (2) Water extraction: Mix the crushed black tea leaves with water in a ratio of 1:10-30, heat to 85-95°C, and reflux for 1.5-2.5 hours to obtain a mixed solution; (3) Centrifugal separation: centrifuge the mixed solution, take the supernatant, and obtain the black tea extract; (4) Fermentation treatment: transfer the black tea extract to the culture medium and add fermentation bacteria; (5) Collecting the fermented product: After fermentation is completed, the fermented product is broken into cells and then centrifuged to obtain the supernatant to obtain the black tea fermented liquid; (6) Filtration and concentration: The black tea fermentation liquid is filtered and then concentrated.

[0010] Preferably, in S4, cotton cloth soaked in plant extract is used within 1-3 hours of the initial fermentation of the B-grade tea leaves, and cotton cloth soaked in pure water is used for subsequent fermentation to obtain fermented C-grade tea leaves.

[0011] Preferably, in S5, when the moisture content of the B-grade tea leaves after drying is reduced to 30% by weighing and measuring, the fermentation is continued to obtain the fermented C-grade tea leaves.

[0012] Preferably, the fresh tea leaves are one or any combination of a single bud, one bud and one leaf, one bud and two leaves, a pair of leaves of equal tenderness, or one bud and multiple leaves.

[0013] Preferably, the length of the Dendrobium officinale leaf blade is between 10-20 cm, and the width is between 1-2 cm.

[0014] Preferably, the molar concentration of the black tea extract is 5% to 15%.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. The process for making Dendrobium officinale black tea provided by the present invention is to improve the overall quality of tea leaves while maintaining the fermentation humidity during the fermentation process, and to use plant extracts in the early stage of tea fermentation, and to use purified water in the later stage. The plant extracts are rich in a variety of aroma components and flavor substances. The use of these extracts in the early stage of fermentation can effectively transfer these aromas and flavors to tea leaves, thereby enhancing the aroma and taste of tea leaves. The enzymes and microorganisms in these extracts can effectively promote chemical reactions in tea leaves, improve the quality and taste of tea leaves, and use these extracts in the early stage of fermentation to accelerate the fermentation process and enable tea leaves to reach the desired fermentation degree faster. Using purified water in the later stage of fermentation can reduce the interference of plant extracts with the final aroma of tea leaves. Purified water will not make additional contributions or interference to the aroma of tea leaves, making the aroma of tea leaves more pure and natural. By using plant extracts in the early stage of fermentation and using purified water in the later stage, the fermentation process and aroma characteristics of tea leaves can be better controlled, thereby improving the overall quality of tea leaves. In particular, when the aroma of grade B tea is not good, the aroma of grade C tea can be adjusted by increasing the concentration of the plant extract in which the cotton cloth is immersed. Thus, by using cotton cloth with different concentrations of plant extract, the aroma of grade B tea with uneven aroma concentration can be adjusted to a certain extent, thereby producing grade C tea with uniform aroma.

[0016] 2. The production process of Dendrobium officinale black tea provided by the present invention is slightly dried during the fermentation process, that is, low-temperature drying. Low-temperature drying can effectively inhibit the activity of enzymes in tea leaves, reduce the further transformation of chemical components in tea leaves, and thus maintain the original flavor and color of tea leaves. In addition, proper treatment of tea leaves before fermentation, such as drying, rolling, etc., can improve the absorption capacity of tea leaves to aroma components. Low-temperature drying can promote the formation of certain volatile aroma components in tea leaves, making the aroma of tea leaves more intense and lasting, and can also reduce the content of bitter and astringent components in tea leaves, making the taste of tea leaves softer and sweeter. At the same time, it reduces the loss of soluble substances in tea leaves, improves the resistance of tea leaves to brewing, and allows tea leaves to be brewed multiple times while still maintaining a good taste and aroma. Low-temperature drying can also reduce the decomposition of chlorophyll in tea leaves, keep the green color of tea leaves, and make the appearance of tea leaves more beautiful. It can reduce the breakage of tea leaves during processing and maintain the integrity and beauty of tea leaves. DETAILED DESCRIPTION

[0017] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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.

[0018] The present invention provides a process for making Dendrobium officinale black tea, comprising the following embodiments: Example

[0019] This embodiment includes the following steps: S1. Raw material pretreatment: Wash and dry the Dendrobium officinale leaves and mix them with fresh tea leaves in a weight ratio of 3:7, spread them evenly in a thickness of no more than 3 cm, and then leave them at night for 8h-10h; S2. Withering: Spread the tea leaves thinly and air-dry them in the soft sunlight before 10:00 or after 16:00 for about 1-2 hours. The thickness of the thin spread should be 1-3 cm. Turn the leaves over every 15 minutes to obtain the withered A-grade tea leaves. S3, rolling: putting the A-grade tea leaves into the rolling barrel of the rolling machine, and rolling the A-grade tea leaves for at least 30 minutes in the order of light rolling 1-heavy rolling 1-light rolling 2-heavy rolling 2-light rolling 3, until the rolled leaves are partially red or light yellow-green, and then breaking up the blocks and shaking them apart to obtain rolled B-grade tea leaves; S4, fermentation: the tea leaves of grade B are placed in an open container, the top of the container is covered with cotton cloth to cover the tea leaves of grade B, the cotton cloth is soaked with plant extract, and the tea leaves of grade B slowly turn red over 8-12 hours, during which the cotton cloth is re-soaked every 1 hour; S5, light drying: In S4, at the initial fermentation stage of the B tea leaves, the tea leaves are dried at a temperature of 40-60° C. for 1-2 hours and then continued to ferment to obtain the fermented C tea leaves; S6, full drying: 500g of C-grade tea leaves are placed in a baking drying oven, covered with dry cotton cloth, and baked twice, firstly with high heat for a short time of 2-3min, the temperature of which is controlled at 200-250°C, to obtain D-grade tea leaves; the D-grade tea leaves are spread in a ventilated and cool place for 30-60min, and then with low heat for a long time of 2-3h until fully dry, the temperature of which is controlled at 100-150°C, to obtain E-grade tea leaves; S8. Natural annealing: Put product E into a cotton bag while it is still hot, place it in a cool, dark and dry place for at least one month, and then naturally transform and anneal to obtain the finished tea product.

[0020] In the present embodiment, raw material should select high-quality Dendrobium officinale leaf, which is in the shape of an elongated strip, with smooth edges, thick leaves, bright green color, glossy surface, free from pests and diseases and mechanical damage, and the leaf size is moderate, and the length is generally between 10-20 centimetres, and the width is between 1-2 centimetres. High-quality Dendrobium officinale leaf is usually plucked in May-June of each year, and now the leaf growth is vigorous, and the effective component content is higher. High-quality Dendrobium officinale leaf is cleaned, dried and then standby, and then evenly and thinly spread on a round flat, placed one night. The second day, thinly spread on a bamboo mat under the soft sunlight before 10 o'clock or after 16 o'clock for about 1-2 hours, and flipped once every quarter of an hour, the action is gentle, to the atrophy of leaf shape, the leaf quality is soft, the stem vein loses water and atrophies, and the tortuosity is not easy to break brittle, and the leaf color turns to dark green, and the surface gloss disappears, and the grassy smell of fresh leaves subsides, revealing the unique fragrance of withered leaves. Tea leaves are subsequently kneaded, and the process can use a kneading machine, and it can also be carried out manually. When operating manually: take 2 taels of withered leaf ball on a bamboo mat, use your waist to drive your upper body, push forward with force, stack it back in front of your body and push again, and keep pushing in a continuous cycle. The manual rolling process generally adopts the principle of light-heavy-light, until the rolled leaves are partially red or light yellow-green, hold the rolled leaves tightly with your hands, and the tea juice overflows. After letting go, the leaf ball does not fall apart and is a little sticky, which is moderate. Then use a purely hand-woven bamboo frame, place the rolled tea leaves in the frame for tea fermentation, cover them with soaked cotton cloth, use charcoal to cook plant extract in a stove to continuously increase temperature and humidity, and the tea leaves slowly turn red after 8-12 hours. During this period, the cotton cloth must be kept moist at all times. The drying process of tea after fermentation can be done in a baking drying box or by covering a bamboo baking cage with dry cotton cloth. Only 1 jin of fermented leaves can be placed in each cage and dried with charcoal fire in two times. First, use high fire for short baking. When the dry leaves are pinched by hand, they should feel slightly prickly, but the leaves are still soft and can be folded without breaking. When you hold the tea leaves tightly, they will loosen and have a mellow aroma. Then use low fire for long baking to enhance the aroma and bake until they are fully dry. After they are fully dry, you can rub them with your hands to form powder with obvious fragrance. Finally, take the raw tea in cotton bags while it is still hot and place them in a cool, dark and dry place. It needs to be placed for more than one month for natural transformation and annealing.

[0021] In this embodiment, in the fermentation process of S4, in order to improve the overall quality of tea while maintaining the fermentation humidity, the tea is provided with fermentation humidity by covering the tea with cotton cloth soaked with plant extract. Preferably, plant extract can be used in the early stage of tea fermentation, and purified water is used in the later stage. Plant extracts are rich in a variety of aroma components and flavor substances. Using these extracts in the early stage of fermentation can effectively transfer these aromas and flavors to tea, thereby enhancing the aroma and taste of tea. The enzymes and microorganisms in these extracts can effectively promote chemical reactions in tea, improve the quality and taste of tea, and use these extracts in the early stage of fermentation to accelerate the fermentation process and enable tea to reach the desired fermentation degree faster. Using purified water in the later stage of fermentation can reduce the interference of plant extracts on the final aroma of tea. Purified water will not make additional contributions or interference to the aroma of tea, making the aroma of tea more pure and natural. By using plant extracts in the early stage of fermentation and using purified water in the later stage, the fermentation process and aroma characteristics of tea can be better controlled, thereby improving the overall quality of tea. In particular, when the sensory aroma of grade B tea is not mellow enough, the aroma of grade C tea can be adjusted by increasing the concentration of the plant extract in which the cotton cloth is immersed. Thus, by using cotton cloth with different concentrations of plant extract, the aroma of grade B tea with uneven aroma concentration can be adjusted to a certain extent, thereby producing mellow, rich and uniform grade C tea.

[0022] In this embodiment, the fermentation process of S4 is slightly dried in S5, i.e., low-temperature drying. Low-temperature drying can effectively inhibit the activity of enzymes in tea leaves, reduce the further transformation of chemical components in tea leaves, and thus maintain the original flavor and color of tea leaves. Moreover, proper treatment of tea leaves before fermentation, such as drying, rolling, etc., can improve the absorption capacity of tea leaves to aroma components. Low-temperature drying can promote the formation of certain volatile aroma components in tea leaves, making the aroma of tea leaves more intense and lasting, and can also reduce the content of bitter and astringent components in tea leaves, making the taste of tea leaves softer and sweeter. At the same time, it reduces the loss of soluble substances in tea leaves, improves the resistance of tea leaves to brewing, and allows tea leaves to be brewed multiple times while still maintaining good taste and aroma. Low-temperature drying can also reduce the decomposition of chlorophyll in tea leaves, keep the green color of tea leaves, and make the appearance of tea leaves more beautiful. It can reduce the breakage of tea leaves during processing and maintain the integrity and beauty of tea leaves.

[0023] More specifically, in S4, the container can be preferably a bamboo basket, and the bottom and top of the bamboo basket are covered with soaked cotton cloth to wrap the B-grade tea leaves, and water or plant extract is boiled in a charcoal stove for continuous humidification. A pit is left in the middle of the B-grade tea leaves, and the bottom cotton cloth can be seen in the pit, and the two layers of cotton cloth are in contact. The bottom cotton cloth can prevent liquid vapor from directly contacting the tea leaves, so that the tea leaves can be evenly moistened, and the upper and lower layers of cotton cloth are in contact, and the wetness of the two layers of cotton cloth can be uniform through capillary action, thereby improving the uniformity of tea leaves moistening.

[0024] More specifically, in S4, the plant extract is a black tea extract, and the preparation steps of the black tea extract are as follows: (1) Tea leaves crushing: crushing the fresh leaves of black tea tree; (2) Water extraction: Mix the crushed black tea leaves with water in a ratio of 1:10-30, heat to 85-95°C, and reflux for 1.5-2.5 hours to obtain a mixed solution; (3) Centrifugal separation: centrifuge the mixed solution, take the supernatant, and obtain the black tea extract; (4) Fermentation treatment: transfer the black tea extract to the culture medium and add fermentation bacteria; (5) Collecting the fermented product: After fermentation is completed, the fermented product is broken into cells and then centrifuged to obtain the supernatant to obtain the black tea fermented liquid; (6) Filtration and concentration: The black tea fermentation liquid is filtered and then concentrated.

[0025] The black tea extract contains rich polyphenols and enzymes, such as polyphenol oxidase and peroxidase, which can promote the fermentation process of tea leaves, accelerate the fermentation process in the early stage of tea fermentation, and make the tea leaves reach the ideal fermentation degree faster. Preferably, the molar concentration of the black tea extract is 5% to 15%.

[0026] More specifically, in S5, when the moisture content of the dried tea leaves of type B is reduced to 30% by weighing, the fermentation is continued. Proper treatment of the tea leaves before fermentation, such as drying and rolling, can reduce the moisture content of the tea leaves and improve the tea leaves' ability to absorb aroma components.

[0027] More specifically, the fresh tea leaves are one or any combination of a single bud, one bud and one leaf, one bud and two leaves, pairs of leaves of equal tenderness, or one bud and multiple leaves.

[0028] More specifically, in S3, the time for light kneading 1 is 12-15 minutes, and the upper cover of the kneading barrel just touches the tea leaves; the time for heavy kneading 1 is 5-8 minutes, and the upper cover of the kneading barrel is pressed down until it touches the tea leaves and then pressed down 3-5 cm; the time for light kneading 2 is 3-6 minutes, and the upper cover of the kneading barrel returns to the top of the kneading barrel; the time for heavy kneading 2 is 8-10 minutes, and the upper cover of the kneading barrel is pressed down until it touches the tea leaves and then pressed down 3-5 cm; the time for light kneading 3 is 2-5 minutes, and the upper cover of the kneading barrel returns to the top of the kneading barrel, and after kneading, the blocks are deblocked and shaken to obtain B-grade tea leaves.

[0029] In this embodiment, by using black tea extract and adding a micro-drying step, the fermentation time of the tea leaves is controlled to about 10 hours, and the sensory aroma of the fermented tea leaves is mellow and strong, which improves the overall quality of the tea leaves.

[0030] Comparative Example 1: S1. Raw material pretreatment: Wash and dry the Dendrobium officinale leaves and mix them with fresh tea leaves in a weight ratio of 3:7, spread them evenly in a thickness of no more than 3 cm, and then leave them at night for 8h-10h; S2. Withering: Spread the tea leaves thinly and air-dry them in the soft sunlight before 10:00 or after 16:00 for about 1-2 hours. The thickness of the thin spread should be 1-3 cm. Turn the leaves over every 15 minutes to obtain the withered A-grade tea leaves. S3, rolling: putting the A-grade tea leaves into the rolling barrel of the rolling machine, and rolling the A-grade tea leaves for at least 30 minutes in the order of light rolling 1-heavy rolling 1-light rolling 2-heavy rolling 2-light rolling 3, until the rolled leaves are partially red or light yellow-green, and then breaking up the blocks and shaking them apart to obtain rolled B-grade tea leaves; S4, fermentation: the tea leaves of grade B are placed in an open container, the top of the container is covered with cotton cloth to cover the tea leaves of grade B, the cotton cloth is soaked with pure water, and the tea leaves of grade B slowly turn red over 8-12 hours, during which the cotton cloth is re-soaked every 1 hour; S5, light drying: In S4, at the initial fermentation stage of the B tea leaves, the tea leaves are dried at a temperature of 40-60° C. for 1-2 hours and then continued to ferment to obtain the fermented C tea leaves; S6, full drying: 500g of C-grade tea leaves are placed in a baking drying oven, covered with dry cotton cloth, and baked twice, firstly with high heat for a short time of 2-3min, the temperature of which is controlled at 200-250°C, to obtain D-grade tea leaves; the D-grade tea leaves are spread in a ventilated and cool place for 30-60min, and then with low heat for a long time of 2-3h until fully dry, the temperature of which is controlled at 100-150°C, to obtain E-grade tea leaves; S7. Natural annealing: Put product E into a cotton bag while it is still hot, place it in a cool, dark and dry place for at least one month, and then naturally transform and anneal to obtain the finished tea product.

[0031] The difference between Comparative Example 1 and Example 1 is that no plant extract is used in S4.

[0032] The comparison results are: the fermentation time was extended to more than 12h, and the sensory aroma was average.

[0033] Comparative Example 2: S1. Raw material pretreatment: Wash and dry the Dendrobium officinale leaves and mix them with fresh tea leaves in a weight ratio of 3:7, spread them evenly in a thickness of no more than 3 cm, and then leave them at night for 8h-10h; S2. Withering: Spread the tea leaves thinly and air-dry them in the soft sunlight before 10:00 or after 16:00 for about 1-2 hours. The thickness of the thin spread should be 1-3 cm. Turn the leaves over every 15 minutes to obtain the withered A-grade tea leaves. S3, rolling: putting the A-grade tea leaves into the rolling barrel of the rolling machine, and rolling the A-grade tea leaves for at least 30 minutes in the order of light rolling 1-heavy rolling 1-light rolling 2-heavy rolling 2-light rolling 3, until the rolled leaves are partially red or light yellow-green, and then breaking up the blocks and shaking them apart to obtain rolled B-grade tea leaves; S4, fermentation: the tea leaves of grade B are placed in an open container, the top of the container is covered with cotton cloth to cover the tea leaves of grade B, the cotton cloth is soaked with pure water or plant extract, and the tea leaves of grade B slowly turn red over 8-12 hours, during which the cotton cloth is re-soaked every 1 hour; S6, full drying: 500g of C-grade tea leaves are placed in a baking drying oven, covered with dry cotton cloth, and baked twice, firstly with high heat for a short time of 2-3min, the temperature of which is controlled at 200-250°C, to obtain D-grade tea leaves; the D-grade tea leaves are spread in a ventilated and cool place for 30-60min, and then with low heat for a long time of 2-3h until fully dry, the temperature of which is controlled at 100-150°C, to obtain E-grade tea leaves; S7. Natural annealing: Put product E into a cotton bag while it is still hot, place it in a cool, dark and dry place for at least one month, and then naturally transform and anneal to obtain the finished tea product.

[0034] The difference between Comparative Example 2 and Example 1 is that step S5 is missing, that is, micro-drying is not performed in the initial fermentation stage of S4.

[0035] The comparison results are: the fermentation time remains unchanged, between 8-12h, and the sensory aroma is not mellow enough.

[0036] Comparative Example 3: S1. Raw material pretreatment: Wash and dry the Dendrobium officinale leaves and mix them with fresh tea leaves in a weight ratio of 3:7, spread them evenly in a thickness of no more than 3 cm, and then leave them at night for 8h-10h; S2. Withering: Spread the tea leaves thinly and air-dry them in the soft sunlight before 10:00 or after 16:00 for about 1-2 hours. The thickness of the thin spread should be 1-3 cm. Turn the leaves over every 15 minutes to obtain the withered A-grade tea leaves. S3, rolling: putting the A-grade tea leaves into the rolling barrel of the rolling machine, and rolling the A-grade tea leaves for at least 30 minutes in the order of light rolling 1-heavy rolling 1-light rolling 2-heavy rolling 2-light rolling 3, until the rolled leaves are partially red or light yellow-green, and then breaking up the blocks and shaking them apart to obtain rolled B-grade tea leaves; S4, fermentation: the tea leaves of grade B are placed in an open container, the top of the container is covered with cotton cloth to cover the tea leaves of grade B, the cotton cloth is soaked with pure water, and the tea leaves of grade B slowly turn red over 8-12 hours, during which the cotton cloth is re-soaked every 1 hour; S6, full drying: 500g of C-grade tea leaves are placed in a baking drying oven, covered with dry cotton cloth, and baked twice, firstly with high heat for a short time of 2-3min, the temperature of which is controlled at 200-250°C, to obtain D-grade tea leaves; the D-grade tea leaves are spread in a ventilated and cool place for 30-60min, and then with low heat for a long time of 2-3h until fully dry, the temperature of which is controlled at 100-150°C, to obtain E-grade tea leaves; S7. Natural annealing: Put product E into a cotton bag while it is still hot, place it in a cool, dark and dry place for at least one month, and then naturally transform and anneal to obtain the finished tea product.

[0037] The difference between Comparative Example 3 and Example 1 is that no plant extract is used in S4 and step S5 is missing, that is, no micro-drying is performed in the initial fermentation stage of S4.

[0038] The comparison results are: the fermentation time was prolonged, exceeding 12h, and the sensory aroma was not mellow enough.

[0039] The above embodiments are only exemplary embodiments of the present application and are not intended to limit the present application. The protection scope of the present application is defined by the claims. Those skilled in the art may make various modifications or equivalent substitutions to the present application within the essence and protection scope of the present application, and such modifications or equivalent substitutions shall also be deemed to fall within the protection scope of the present application.

Claims

1. A process for producing Dendrobium officinale black tea, characterized in that: The following steps are involved: S1. Raw material pretreatment: Wash and dry the Dendrobium officinale leaves and mix them with fresh tea leaves in a weight ratio of 3:7, spread them evenly in a thickness of no more than 3 cm, and then leave them at night for 8h-10h; S2. Withering: Spread the tea leaves thinly and air-dry them in the soft sunlight before 10:00 or after 16:00 for about 1-2 hours. The thickness of the thin spread should be 1-3 cm. Turn the leaves over every 15 minutes to obtain the withered A-grade tea leaves. S3, rolling: putting the A-grade tea leaves into the rolling barrel of the rolling machine, and rolling the A-grade tea leaves for at least 30 minutes in the order of light rolling 1-heavy rolling 1-light rolling 2-heavy rolling 2-light rolling 3, until the rolled leaves are partially red or light yellow-green, and then breaking up the blocks and shaking them apart to obtain rolled B-grade tea leaves; S4, fermentation: the tea leaves of grade B are placed in an open container, the top of the container is covered with cotton cloth to cover the tea leaves of grade B, the cotton cloth is soaked with pure water or plant extract, and the tea leaves of grade B slowly turn red over 8-12 hours, during which the cotton cloth is re-soaked every 1 hour; S5, light drying: In S4, at the initial fermentation stage of the B tea leaves, the tea leaves are dried at a temperature of 40-60° C. for 1-2 hours and then continued to ferment to obtain the fermented C tea leaves; S6, full drying: 500g of C-grade tea leaves are placed in a baking drying oven, covered with dry cotton cloth, and baked twice, firstly with high heat for a short time of 2-3min, the temperature of which is controlled at 200-250°C, to obtain D-grade tea leaves; the D-grade tea leaves are spread in a ventilated and cool place for 30-60min, and then with low heat for a long time of 2-3h until fully dry, the temperature of which is controlled at 100-150°C, to obtain E-grade tea leaves; S8. Natural annealing: Put product E into a cotton bag while it is still hot, place it in a cool, dark and dry place for at least one month, and then naturally transform and anneal to obtain the finished tea product.

2. The process for making Dendrobium officinale black tea according to claim 1, characterized in that: In S3, the time of light kneading 1 is 12-15 minutes, and the upper cover of the kneading barrel just touches the tea leaves; the time of heavy kneading 1 is 5-8 minutes, and the upper cover of the kneading barrel is pressed down until it touches the tea leaves and then pressed down 3-5 cm; the time of light kneading 2 is 3-6 minutes, and the upper cover of the kneading barrel returns to the top of the kneading barrel; the time of heavy kneading 2 is 8-10 minutes, and the upper cover of the kneading barrel is pressed down until it touches the tea leaves and then pressed down 3-5 cm; the time of light kneading 3 is 2-5 minutes, and the upper cover of the kneading barrel returns to the top of the kneading barrel, and after kneading, the tea blocks are deblocked and shaken to obtain B grade tea leaves.

3. The process for making Dendrobium officinale black tea according to claim 2, characterized in that: In S4, the bottom and top of the container are respectively covered with soaked cotton cloth to wrap the B-grade tea leaves, and a pit is left in the middle of the pile of the B-grade tea leaves, through which the bottom layer of cotton cloth can be seen, and the two layers of cotton cloth are in contact.

4. The process for making Dendrobium officinale black tea according to claim 3, characterized in that: In S4, the plant extract is a black tea extract, and the preparation steps of the black tea extract are as follows: (1) Tea leaves crushing: crushing the fresh leaves of black tea tree; (2) Water extraction: Mix the crushed black tea leaves with water in a ratio of 1:10-30, heat to 85-95°C, and reflux for 1.5-2.5 hours to obtain a mixed solution; (3) Centrifugal separation: centrifuge the mixed solution, take the supernatant, and obtain the black tea extract; (4) Fermentation treatment: transfer the black tea extract to the culture medium and add fermentation bacteria; (5) Collecting the fermented product: After fermentation is completed, the fermented product is broken into cells and then centrifuged to obtain the supernatant to obtain the black tea fermented liquid; (6) Filtration and concentration: The black tea fermentation liquid is filtered and then concentrated.

5. The process for making Dendrobium officinale black tea according to claim 4, characterized in that: In S4, cotton cloth soaked in plant extract is used within 1-3 hours of the initial fermentation of the B-grade tea leaves, and cotton cloth soaked in pure water is used for subsequent fermentation to obtain fermented C-grade tea leaves.

6. The process for making Dendrobium officinale black tea according to claim 5, characterized in that: In S5, when the moisture content of the B-grade tea leaves after drying is reduced to 30% by weighing and measuring, the fermentation is continued to obtain the fermented C-grade tea leaves.

7. The process for making Dendrobium officinale black tea according to claim 6, characterized in that: The fresh tea leaves are one or any combination of a single bud, one bud and one leaf, one bud and two leaves, pairs of leaves of equal tenderness, or one bud and multiple leaves.

8. The process for making Dendrobium officinale black tea according to claim 7, characterized in that: The length of the Dendrobium officinale leaf blade is between 10-20 cm, and the width is between 1-2 cm.

9. The process for making Dendrobium officinale black tea according to claim 8, characterized in that: The molar concentration of the black tea extract is 5% to 15%.