Cold-brewed black tea and a method of making the same

Abstract

The present application relates to black tea preparation technical field, disclose a kind of preparation method of cold-brewed black tea, comprising the following steps: step (1): after picking raw material is successively withered, rolling, fermentation, and is initially baked, and the moisture content of raw material after initial baking is 25%~35%;Step (2): after the raw material of initial baking is pressed and shaped, it is scattered, and repeated at least 8 times;Step (3): the raw material treated by step (2) is successively re-baked, screened, and granular product is obtained.The preparation method can destroy the cell wall of tea leaves to the greatest extent by controlling the moisture content of raw material after initial baking, and also can ensure the integrity of tea leaves, the cold-brewed black tea prepared by the preparation method is granular, not only beautiful, but also fast, and the leaf bottom is the flaky structure of tea itself, and the tea dust is less.

Description

Technical Field

[0001] This invention relates to the field of black tea preparation technology, specifically to a cold-brewed black tea and its preparation method. Background Technology

[0002] Black tea is a fully fermented tea, and its processing includes withering, rolling, fermentation, and drying. It gets its name from the red color of its liquor, and its rich flavor and unique aroma make it a favorite among tea lovers.

[0003] The production process of black tea involves several main steps. First, tea farmers harvest suitable tea varieties at the appropriate season, typically selecting tender buds and leaves. After harvesting, the tea leaves are placed in a cool, shaded place to wither, naturally losing some moisture, which prepares them for subsequent rolling and fermentation. Next, the tea leaves are rolled, causing the cells to break and release tea juice; this process aids in subsequent fermentation and color formation. The rolled tea leaves undergo fermentation under specific temperature and humidity conditions, gradually darkening their color and enhancing their aroma. After fermentation, the tea leaves are baked or sun-dried to remove moisture, stopping the fermentation process and preserving the tea's aroma and flavor. Finally, the dried tea leaves are sifted to remove broken leaves, selecting the high-quality leaves for packaging.

[0004] Traditional hot water brewing of tea involves temperatures between 80 and 100 degrees Celsius, pouring in water and steeping for just a few minutes, which brings out the best characteristics of the tea. With the fast pace of modern life, cold-brewed tea has become increasingly popular. The process is relatively simple: just mix tea leaves with cold water and let it steep for a while before drinking.

[0005] However, the steeping speed of cold-brewed tea is more related to the cell walls of the tea leaves. During the steeping process, the degree of cell wall breakage affects the release rate of chemical components in the tea (such as tea polyphenols, caffeine, and amino acids). When the cell walls of the tea leaves are broken, the components in the tea are more easily extracted by water, thus increasing the steeping speed. Generally speaking, the smaller the tea leaves, the faster the steeping speed. This is because broken tea leaves and tea dust can come into more contact with water than whole tea leaves, thereby accelerating the release of tea components. However, these broken tea leaves and tea dust can significantly affect the taste.

[0006] CN111109375A discloses a method for making cold-brewed black tea, including the following steps: Harvesting raw materials: Harvesting fresh leaves and stems, wherein the fresh leaves and stems are the parts 9cm-11cm in length, 1cm to 3cm below the highest bud; Withering: Placing the raw materials in a bellows for dehydration, with a blower blowing air below the bellows and an ultraviolet lamp above, controlling the time to 1 to 2 days; Rolling; Fermentation: Packing the materials into bags and placing them in a fermentation box for fermentation, with the temperature in the fermentation box at 30-50 degrees Celsius and the humidity at 75%-85%, for 1 to 2 days; Drying; Grinding: Grinding the raw materials to 1.15-1.35mm. 2 The raw materials utilize portions unwanted by existing tea-making processes, significantly reducing costs. By controlling fermentation time, temperature, and humidity, the fermentation conversion rate is improved, and the raw materials are pulverized to 1.15-1.35mm. 2 This allows the cold-brewed black tea to release its flavor quickly in a lower temperature brewing environment, resulting in a tea with no bitterness and a good taste.

[0007] The above technical solutions only control the selection of raw materials and the time, temperature and humidity of fermentation, but these do not directly affect the cell walls of tea leaves, resulting in a slow brewing speed. Summary of the Invention

[0008] The purpose of this application is to solve the aforementioned problems and provide a method for preparing cold-brewed black tea. This method, by controlling the moisture content of the raw materials after initial drying and combining it with at least eight pressing and shaping processes, can maximally disrupt the cell walls of the tea leaves while ensuring the integrity of the tea leaves. The cold-brewed black tea prepared using this method is granular, which is not only aesthetically pleasing but also results in a fast brewing speed. The tea leaves at the bottom of the cup retain the leaf's original flaky structure with minimal tea dust. Furthermore, this application also provides the cold-brewed black tea prepared using this method.

[0009] To achieve the above objectives, this application provides the following technical solution:

[0010] A method for preparing cold-brewed black tea includes the following steps:

[0011] Step (1): After harvesting, the raw materials are withered, kneaded, fermented and then initially dried. The moisture content of the raw materials after initial drying is 25% to 35%.

[0012] Step (2): Press and shape the pre-dried raw material, then break it up, repeating at least 8 times;

[0013] Step (3): The raw materials obtained in step (2) are dried and sieved in sequence to obtain granular products.

[0014] In step (1), the moisture content of the raw material after initial drying can be 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, or 35%, but is not limited to the listed values. Other unlisted values ​​are acceptable as long as they are within this range.

[0015] In step (2), the number of repetitions can be 8, 9, 10, 11, or 12, but is not limited to the listed values. Any other unlisted values ​​within this range are acceptable. It should also be noted that, under the premise of satisfying the shape requirement, the fewer the number of repetitions, the better.

[0016] Preferably, in step (1), the raw materials are selected tea buds, leaves, buds, and tender stems.

[0017] Preferably, in step (1), the initial drying temperature is 100-105°C and the time is 11-14 min.

[0018] The selected buds, leaves, terminal buds, and tender stems should meet the standards of GB 2762 and GB 2763.

[0019] The initial drying temperature can be 100℃, 101℃, 102℃, 103℃, 104℃, or 105℃, but is not limited to the listed values. Other unlisted values ​​are acceptable as long as they fall within this range.

[0020] The initial drying time can be 11 min, 12 min, 13 min, or 14 min, but it is not limited to the listed values. Any other unlisted values ​​within this range are acceptable.

[0021] It should be noted that changing the initial drying temperature and time is only intended to achieve the desired moisture content more quickly, and has no impact on the subsequent results.

[0022] Preferably, in step (2), the pressing includes a first stage and a second stage. Specifically, step (2) involves: placing the pre-dried raw material into a tea shaping machine and pressing it with a base pressure of 6-8 MPa for 90-100 seconds. After pressing, the resulting blocky raw material is placed into a deblocking machine to break it up. The pressure for each subsequent press is increased by 1-2 MPa, while the time remains the same. This process is repeated at least 7 times, constituting the first stage.

[0023] The second phase involves applying the maximum pressure and time from the first phase, followed by at least one more suppression.

[0024] The first stage can be repeated 7, 8, 9, or 10 times, and the second stage can be repeated 1, 2, or 3 times, but is not limited to the listed values. Other unlisted values ​​are acceptable as long as they fall within this range. Under the premise of achieving the desired result, the fewer repetitions, the better.

[0025] The basic pressure can be 6MPa, 6.5MPa, 7MPa, 7.5MPa, or 8MPa, but is not limited to the listed values. Any other unlisted values ​​within this range are acceptable.

[0026] The pressing time can be 90s, 91s, 92s, 93s, 94s, 95s, 96s, 97s, 98s, 99s, or 100s, but is not limited to the listed values. Any other unlisted values ​​within this range are acceptable.

[0027] When repeating this step, the pressure for each subsequent step should be increased by 1 MPa, 1.2 MPa, 1.4 MPa, 1.6 MPa, 1.8 MPa, or 2 MPa, but is not limited to the listed values. Any other unlisted values ​​within this range are acceptable.

[0028] The tea shaping machine used is: Jiayou 6CKL-90Z.

[0029] Preferably, in step (2), the number of repetitions is 8 to 12 times, and more preferably, the number of repetitions is 8 to 10 times.

[0030] Preferably, in step (3), the re-drying temperature is 105-110℃ and the time is 13-16 min, and the moisture content of the raw material after re-drying does not exceed 6%.

[0031] The re-drying temperature can be 105℃, 106℃, 107℃, 108℃, 109℃, or 110℃, but is not limited to the listed values. Other unlisted values ​​are acceptable as long as they are within this range.

[0032] The re-drying time can be 13 min, 14 min, 15 min, or 16 min, but it is not limited to the listed values. Any other unlisted values ​​within this range are acceptable.

[0033] It should be noted that the purpose of changing the temperature and time of the re-drying is simply to achieve the required moisture content more quickly.

[0034] Preferably, both the initial drying in step (1) and the re-drying in step (3) are carried out using a chain dryer.

[0035] Preferably, in step (3), the mesh size of the sieve used for sieving is 40 to 50 mesh. 40 mesh, 45 mesh, and 50 mesh can be used, but are not limited to the listed values; any other unlisted value within this range is acceptable.

[0036] Meanwhile, the present invention also provides a cold-brewed black tea, which is prepared by the above preparation method, and the cold-brewed black tea is in granular form.

[0037] Compared with the prior art, the beneficial effects of this application are:

[0038] This application controls the moisture content of the raw materials after initial drying and combines it with at least 8 pressing and shaping processes to maximize the destruction of the cell walls of the tea leaves while ensuring the integrity of the tea leaves. The cold-brewed black tea prepared using this method is granular, which is not only aesthetically pleasing but also allows for rapid brewing. The tea leaves at the bottom have the original leaf structure with minimal tea dust. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the granular product prepared according to Example 1 of the present invention. Detailed Implementation

[0040] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0041] In the following embodiments, unless otherwise specified, the selected tea variety is Yinghong No. 9.

[0042] Example 1

[0043] A method for preparing cold-brewed black tea includes the following steps:

[0044] Step (1): Select tea buds, leaves, buds, and tender stems as raw materials. After picking, the raw materials are withered, rolled, fermented, and then initially dried. The moisture content of the raw materials after initial drying is 30%.

[0045] Step (2): Place the pre-dried raw material into the tea shaping machine, press it for the first time with a base pressure of 7MPa and a pressing time of 90s. After pressing, put the resulting blocky raw material into the deblocking machine to break it up. The pressure for each subsequent press is increased by 2MPa, while the time remains the same. Repeat this process 7 times for the first stage.

[0046] The second phase begins with the same amount of pressure and time as the first phase, followed by another round of suppression.

[0047] Step (3): The raw material obtained in step (2) is dried again until the moisture content is 5%; after sieving with a 40-mesh sieve, granular products are obtained.

[0048] Example 2

[0049] A method for preparing cold-brewed black tea includes the following steps:

[0050] Step (1): Select tea buds, leaves, buds, and tender stems as raw materials. After picking, the raw materials are withered, rolled, fermented, and then initially dried. The moisture content of the raw materials after initial drying is 25%.

[0051] Step (2): Place the pre-dried raw material into the tea shaping machine, press it for the first time with a base pressure of 8MPa and a pressing time of 100s. After pressing, put the resulting blocky raw material into the deblocking machine to break it up. The pressure for each subsequent press is increased by 1MPa, while the time remains the same. Repeat this process 7 times for the first stage.

[0052] The second phase begins with the same amount of pressure and time as the first phase, followed by another round of suppression.

[0053] Step (3): The raw material obtained in step (2) is dried again until the moisture content is 5%; after sieving with a 40-mesh sieve, granular products are obtained.

[0054] Example 3

[0055] A method for preparing cold-brewed black tea includes the following steps:

[0056] Step (1): Select tea buds, leaves, buds, and tender stems as raw materials. After picking, the raw materials are withered, rolled, fermented, and then initially dried. The moisture content of the raw materials after initial drying is 35%.

[0057] Step (2): Place the pre-dried raw material into the tea shaping machine, press it for the first time with a base pressure of 6MPa and a pressing time of 95s. After pressing, put the resulting blocky raw material into the deblocking machine to break it up. The pressure for each subsequent press is increased by 1.5MPa, while the time remains the same. Repeat this process 7 times for the first stage.

[0058] The second phase begins with the same amount of pressure and time as the first phase, followed by another round of suppression.

[0059] Step (3): The raw material obtained in step (2) is dried again until the moisture content is 5%; after sieving with a 40-mesh sieve, granular products are obtained.

[0060] Example 4

[0061] It is basically the same as Example 1, except that in step (2), the first stage is repeated 8 times and the second stage is not performed.

[0062] Example 5

[0063] It is basically the same as Example 1, except that in step (2), the first stage is repeated 9 times and the second stage is not performed.

[0064] Example 6

[0065] It is basically the same as Example 1, except that in step (2), the minimum pressure of the first stage is used, the pressing time is 90s, and it is repeated 8 times.

[0066] Example 7

[0067] It is basically the same as Example 1, except that in step (2), the maximum pressure of the first stage is used, the pressing time is 90s, and it is repeated 8 times.

[0068] Comparative Example 1

[0069] It is basically the same as Example 1, except that in step (1), the moisture content of the raw material after initial drying is 20%.

[0070] Comparative Example 2

[0071] It is basically the same as Example 1, except that in step (1), the moisture content of the raw material after initial drying is 40%.

[0072] Comparative Example 3

[0073] It is basically the same as Example 1, except that in step (2), the first stage is repeated 6 times.

[0074] Comparative Example 4

[0075] It is basically the same as Example 1, except that in step (2), the second stage is not performed.

[0076] The testing method used is as follows:

[0077] 1. Routine testing;

[0078] This test was conducted using our company's enterprise standard, with the standard batch number Q / YJZY 0002S-2023;

[0079] The testing items are sensory requirements and physicochemical indicators; refer to Tables 3 and 4.

[0080] All embodiments of the present invention conform to enterprise standards.

[0081] 2. Appearance and sensory evaluation

[0082] The products prepared by Examples 1-7 and Comparative Examples 1-4 were first evaluated by appearance, and the results are shown in Table 1. Then, 3g of the products prepared by Examples 1-7 and Comparative Examples 1-4 and conventional black tea were taken and steeped in 150g of water at room temperature for 10 minutes. The color of the tea liquor, aroma, taste and tea leaves were recorded every 5 minutes for a total of 2 times. Sensory evaluation was then carried out, and the results are shown in Table 2.

[0083] Among them, our company's regular black tea is Yinghong No. 9 Classic Red Tea, which is currently on sale.

[0084] Table 1 Results of Appearance Approval

[0085]

[0086]

[0087] Table 2 Sensory evaluation results

[0088]

[0089]

[0090] Table 3 Sensory Requirements

[0091]

[0092] Table 4 Physicochemical Indicators

[0093]

[0094]

[0095] Results analysis:

[0096] 1. Based on the appearance evaluation results of Examples 1-3 and Comparative Examples 1 and 2, it can be seen that when the moisture content after initial drying exceeds the range of 25%-35%, whether it is below or above this range, the appearance is significantly different from that of Examples 1-3. Comparative Example 1 used a moisture content below this range, and although the tea produced was similar to that of Examples 1-3, the excessively low moisture content resulted in reduced physical flexibility of the tea, making it difficult to shape. Moreover, the excessively low moisture content indicates that insufficient water in the tea leaves will make the cell walls of the tea leaves fragile, causing the tea leaves to be easily broken during the pressing process, forming small fragments. Therefore, Comparative Example 1 did not reach Grade 1.

[0097] Comparative Example 2 used a moisture content higher than this range. However, the higher moisture content resulted in better physical flexibility of the tea leaves, making it difficult to form a stable shape. Moreover, the excessive moisture in the tea leaves caused two problems: first, too much water would flow out of the equipment during the pressing process; second, the excessive moisture would increase the toughness and elasticity of the cell walls, making it difficult for the cell walls to be damaged during the pressing process. Therefore, Comparative Example 2 could only reach the second grade.

[0098] 2. As can be seen from the appearance review results of Examples 1 and 4-7, Example 4 used a progressively increasing pressing method of 8 times; while Example 5 used a progressively increasing pressing method of 9 times. The results of both are the same as those of Example 1. Therefore, under the premise of ideal results, the fewer the number of pressing times, the better. This can reduce the pressing time and energy consumption. At the same time, if the last pressing can be completed by holding pressure, there is no need to use the pressurization method, which is also a consideration for energy consumption. Therefore, although Examples 4 and 5 can produce first-class products, considering the time and energy consumption, Example 1 is still the best example.

[0099] In Example 6, except for the first pressure, the pressures were all lower than those in Example 1, but Example 6 could only produce a third-grade product. Example 7 used a higher pressure, which resulted in a tightly flattened strip shape, indicating that excessive pressure can cause flattening.

[0100] 3. As can be seen from the appearance evaluation results of Example 1, Comparative Example 3 and Comparative Example 4, the number of pressing times used in Comparative Example 3 and Comparative Example 4 was less than 8 times. However, in the first stage, the pressing was carried out in an increasing manner. However, the insufficient number of pressing times resulted in the tea leaves not being fully pressed into shape and the cell walls in the tea leaves not being fully destroyed. As a result, the results of Comparative Example 3 and Comparative Example 4 could only reach the third grade.

[0101] 4. As can be seen from the sensory evaluation results of Examples 1-7 and Comparative Examples 1-4, the cell walls in the tea leaves cannot be fully broken down. The integrity of the tea leaf cell walls affects the release of effective components (such as tea polyphenols, amino acids, and caffeine) in the tea leaves. If the cell walls are not fully broken down, the effective components in the tea leaves cannot be fully dissolved, resulting in a weak tea soup flavor, as shown in the results of Examples 6, Comparative Examples 2, 3, and 4. From the results of the conventional black tea in Examples 1-3, it can be seen that the cold-brewed black tea prepared by the preparation method of the present invention has a significantly faster brewing speed, very ideal sensory evaluation results, and also very ideal appearance evaluation results.

[0102] In summary, this invention demonstrates through experiments that when the moisture content of the raw materials after initial drying is within the range of 25% to 35%, and the pressing is performed eight times with progressively increasing pressure in the final pressing cycle, the cell walls of the tea leaves can be broken down to the greatest extent, resulting in a product that... Figure 1It is a granular cold-brewed black tea that is plump, tightly rolled, dark brown, covered with fine hairs, uniform in appearance, and has a fast brewing speed and a bright red and soft leaf base.

[0103] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for preparing cold-brewed black tea, characterized in that, Includes the following steps: Step (1): After harvesting, the raw materials are withered, kneaded, fermented, and then initially dried. The moisture content of the raw materials after initial drying is 25%~35%. Step (2): Press and shape the pre-dried raw material, then break it up, repeating at least 8 times; Step (3): The raw materials obtained in step (2) are successively dried and sieved to obtain granular products; In step (2), the pressing includes a first stage and a second stage. Specifically, step (2) involves: placing the pre-dried raw material into a tea shaping machine and pressing it with a base pressure of 6-8 MPa for 90-100 seconds. After pressing, the resulting blocky raw material is placed into a deblocking machine to break it up. The pressure for each subsequent press is increased by 1-2 MPa from the previous press, while the time remains the same. This process is repeated 7 times, which constitutes the first stage. The second phase begins with the same amount of pressure and time as the first phase, followed by another round of suppression.

2. The method for preparing cold-brewed black tea according to claim 1, characterized in that, In step (1), the raw materials are selected tea buds, leaves, buds, and tender stems.

3. The method for preparing cold-brewed black tea according to claim 1, characterized in that, In step (1), the initial drying temperature is 100~105℃ and the time is 11~14min.

4. The method for preparing cold-brewed black tea according to claim 1, characterized in that, In step (3), the re-drying temperature is 105~110℃ and the time is 13~16min. The moisture content of the raw material after re-drying does not exceed 6%.

5. The method for preparing cold-brewed black tea according to claim 1, characterized in that, Both the initial drying in step (1) and the re-drying in step (3) are performed using a chain dryer.

6. The method for preparing cold-brewed black tea according to claim 1, characterized in that, In step (3), the mesh size of the sieve used for sieving is 40-50 mesh.

7. A cold-brewed black tea, characterized in that, The cold-brewed black tea is prepared by any one of the preparation methods described in claims 1 to 6.

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