Preparation method of flavor-optimized cold-extracted coffee

Abstract

The invention discloses a preparation method of flavor-optimized cold-extracted coffee, and relates to the technical field of coffee beverage processing. In order to solve the problems of lack of flavor oriented optimization, extensive process control and poor product flavor stability in existing cold extraction coffee, the invention provides a cold extraction coffee preparation path based on raw material characteristic regulation and extraction process collaborative optimization. According to the method, key parameters such as raw coffee bean pretreatment, baking degree, grinding particle size, water-powder ratio, extraction time and the like are comprehensively considered, and characteristic expression of low bitterness, rich flavor level and lasting aftertaste of the cold-extracted coffee is realized through experimental optimization. The prepared cold-extracted coffee product better conforms to flavor preference of target consumer groups, has higher flavor stability and repeatability, and is suitable for development and application of instant coffee and special coffee products.

Description

Technical Field

[0001] This invention relates to the field of coffee beverage processing technology, specifically to a method for preparing flavor-optimized cold brew coffee. Background Technology

[0002] Cold brew coffee is a type of coffee beverage made by extracting ground coffee powder with room temperature or cold water over a long period of time. In recent years, it has rapidly gained popularity globally, especially among younger consumers, due to the growing demand for healthier, less stimulating, and more flavorful drinks. Compared to hot brew coffee, cold brew coffee is characterized by lower acidity, less bitterness, a smoother and more mellow taste, and a more stable flavor. It is considered a more suitable and promising beverage for summer, and has broad application prospects in ready-to-drink coffee, specialty coffee, and functional beverages.

[0003] Currently, common methods for preparing cold brew coffee include: full immersion, drip cold brew, ultrasonic-assisted extraction, and high-pressure extraction. While each method has its advantages, they all have varying degrees of technical limitations in practical applications. Room temperature immersion is simple to operate, but it relies on natural diffusion, resulting in low extraction efficiency and a tendency for flavor deviations due to uncontrollable parameters, leading to a bland and unstable flavor profile. Drip cold brew, ultrasonic-assisted extraction, and high-pressure cold brew all suffer from complex or costly equipment, and the stability of flavor during operation is also difficult to guarantee.

[0004] During the preparation process, the flavor profile of cold brew coffee is influenced by a variety of factors, including coffee variety, roasting level, grind size, water-to-coffee ratio, extraction temperature, and equipment structure, resulting in significant differences in flavor expression among the products. Furthermore, these processes often lack targeted development strategies for different coffee types, neglecting diverse consumer needs and the presentation of desired flavors, and lacking a systematic and repeatable technological foundation. The lack of unified standards in raw material processing and powder particle size control also leads to insufficient extraction of flavor compounds and the appearance of off-flavors, further reducing the sensory consistency and industrial adaptability of the product. These problems not only limit the preparation efficiency of cold brew coffee and reduce product stability but also restrict its application in different markets and consumption scenarios. Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention aims to provide a method for preparing flavor-optimized cold brew coffee, achieving efficient and stable preparation of cold brew coffee and effectively solving the problems of lack of flavor-oriented optimization, crude process control, and poor product flavor stability in existing cold brew coffee technologies.

[0006] The technical solution of this invention to solve the above-mentioned technical problems is as follows: A method for preparing flavor-optimized cold brew coffee is provided, comprising the following steps: (1) The coffee beans are sampled, smelled, visually inspected and impurities and defects are determined in sequence to obtain pre-treated coffee beans; When sampling, take a sample of more than 300 g; During olfactory testing, the nose is placed close to the sample, and a deep breath is taken in. The odor is then identified and tested. If there is a foul or unusual odor, the test is rejected. During visual inspection, the sample is spread on a black plate under sunlight or artificial light to check the overall color and uniformity of the coffee beans. When identifying impurities and defects, refer to the defect diagram of green coffee in Appendix C of ISO 10470:2004 for judgment, select defective beans, and ensure that the overall defect rate is ≤10±0.5%; (2) Take 150±10 g of pretreated coffee beans and roast them at 216.85±0.88 ℃ for 300±15 s. After roasting, air cool the coffee beans to room temperature, then seal them in a sealed bag and store them at -20 ℃ for at least 12 h. (3) Grind and sieve the coffee beans, then put them into a filter bag and place it in the filter layer of the extraction cup. Add 10-12 times the weight of water to the coffee beans, and extract with magnetic stirring at 19±1 ℃ for 10 h. Filter to obtain flavor-optimized cold brew coffee.

[0007] Furthermore, in step (2), the coffee beans are roasted to the following color: L*=30.35±0.59, a*=14.63±0.23, b*=20.83±0.67.

[0008] Furthermore, in step (3), coffee beans placed at room temperature are ground directly, while coffee beans placed frozen are ground after being warmed to room temperature.

[0009] Furthermore, in step (3), the coffee beans are sieved through 15-mesh and 20-mesh screens to retain 900-1100 μm coffee bean particles.

[0010] Furthermore, in step (3), magnetic stirring is performed at 200±50 r / min.

[0011] Further, in step (3), the extraction cup includes a cup body, an outer thermochromic shell is provided on the outside of the cup body, a detachable cup lid is provided on the top of the thermochromic shell and the cup body, a base is provided on the bottom of the cup body, a motor and a battery are provided inside the base, and a button is provided on the surface of the base; an inner extraction layer is provided inside the cup body, the top of the inner extraction layer is threaded to the inside of the cup lid, a detachable filter layer is provided at the bottom of the cup body, a filter screen and a magnetic stirrer are provided above the filter layer, and the magnetic stirrer is magnetically coupled to the motor; the thermochromic shell is a double-layer structure, the bottom ends of the two shells are closed to form a sealed interlayer, and a thermosensitive color-changing material is provided inside the interlayer.

[0012] Furthermore, the thermochromic outer shell and the extraction inner layer are made of food-grade pure aluminum, and the thermochromic outer shell changes color at a water temperature of 19±1 ℃.

[0013] Furthermore, the height of the filter screen is one-third of the height of the inner extraction layer, and the filter screen size is 160-200 mesh.

[0014] Furthermore, the magnetic stirrer speed is 100-600 r / min.

[0015] The present invention also provides a flavor-optimized cold brew coffee prepared by the above-mentioned method for preparing flavor-optimized cold brew coffee.

[0016] The present invention has the following beneficial effects: 1. The preparation method of this invention, through the synergistic design of the extraction cup and process parameters, and guided by consumer preferences, develops a cold brew coffee product with a specific flavor, improving sensory quality while also considering ease of operation and scalability of application. The resulting flavor-optimized cold brew coffee liquid exhibits higher consumer acceptance and is particularly suitable for high-sensory-requirement scenarios such as premium ready-to-drink coffee, e-commerce retail, and chain convenience stores, possessing significant market competitive advantages and promotional potential.

[0017] 2. During the preparation process, quantitative standards were set for raw material pretreatment, roasting, grinding, and particle size sieving to ensure that the coffee bean defect rate is ≤10%, the roasting color indicators (L*, a*, b*) are consistent, and the particle size is controlled between 900-1100μm, which significantly improves the consistency of raw materials and the stability of subsequent flavor. A coffee-to-water ratio of 1:10-12 was used, and the extraction was carried out with stirring for 10 hours at a controlled temperature of 19±1℃. The cold extraction parameters were scientifically optimized to achieve efficient release and stable extraction of flavor substances.

[0018] 3. This invention solves the problems of low extraction efficiency, poor flavor stability, and lack of targeted personalized products in the traditional cold brew coffee preparation process. Through optimized structural design, this coffee cup integrates multiple functions such as magnetic stirring, temperature-changing outer shell, and extraction filter layer, enabling integrated operation of temperature control, speed control, and filtration, thus improving the controllability and repeatability of the cold brew process.

[0019] 4. This extraction cup is equipped with a magnetic stirrer and a high-precision filter, which can evenly stir coffee powder and water in a low-temperature environment, improving extraction uniformity and reducing errors caused by manual intervention. This helps to release more flavor compounds and optimize the sensory performance of the final coffee liquid. The filter mesh size is controlled between 160-200 mesh, effectively trapping fine powder residue and improving the clarity and taste of the coffee. It is made of food-grade pure aluminum material, which has good thermal stability and safety. At the same time, the temperature-changing shell can help judge changes in ambient temperature and prevent extraction deviations caused by excessively high or low temperatures. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the extraction cup structure; Figure 2 The results of the preference analysis for cold brew coffee samples with different roasting levels; Figure 3 Results of preference analysis for cold-brewed coffee samples with different extraction times; Figure 4 Results of preference analysis for cold brew coffee samples with different coffee-to-water ratios; Figure 5 Results of preference analysis for cold brew coffee samples with different grinding particle sizes; in, Figure 1 In the middle, 1. Cup lid; 2. Base; 3. Temperature-changing outer shell; 4. Extraction inner layer; 5. Filter screen; 6. Magnetic stirrer; 7. Filter layer. Detailed Implementation

[0021] The principles and features of this invention are described below. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer should be followed. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0022] Example 1 A flavor-optimized cold brew coffee, the preparation method of which includes the following steps: (1) The coffee beans are sampled, smelled, visually inspected and impurities and defects are determined in sequence to obtain pre-treated coffee beans; When sampling, take a sample of more than 300 g; During olfactory testing, the nose is placed close to the sample, and a deep breath is taken in. The odor is then identified and tested. If there is a foul or unusual odor, the test is rejected. During visual inspection, the sample is spread on a black plate under sunlight or artificial light to check the overall color and uniformity of the coffee beans. When identifying impurities and defects, refer to the defect diagram of green coffee in Appendix C of ISO 10470:2004 for judgment, select defective beans, and ensure that the overall defect rate is ≤10±0.5%; (2) Take 150±10 g of pretreated coffee beans and roast them at 216.85±0.88 ℃ for 300±15 s until the coffee bean color is: L*=30.35±0.59, a*=14.63±0.23, b*=20.83±0.67. After roasting, air cool the coffee beans to room temperature, then seal them in a sealed bag and store them at -20 ℃ for at least 12 h. (3) Grind and sieve the coffee beans, then put them into a filter bag and place it in the filter layer of the extraction cup. Add 10-12 times the weight of water to the coffee beans, and extract with magnetic stirring for 10 h at 19±1 ℃ and 200±50 r / min. Filter to obtain flavor-optimized cold brew coffee. During grinding, coffee beans stored at room temperature are ground directly, while frozen coffee beans are ground after being brought to room temperature. During sieving, the beans are passed through 15-mesh and 20-mesh sieves, retaining 900-1100 μm coffee bean particles. The extraction cup includes a cup body with a thermochromic outer shell 3. A lid 1 and a base 2 are mounted on the cup body. An inner extraction layer 4 is located inside the cup body, containing a filter 5 and a magnetic stirrer 6. The filter 5 is located below the magnetic stirrer 6, and a filter layer 7 is located below the magnetic stirrer 6. The thermochromic outer shell 3 and the inner extraction layer 4 are made of food-grade pure aluminum, and the thermochromic outer shell 3 changes color at a water temperature of 19±1 ℃. The height of the filter 5 is one-third the height of the inner extraction layer 4, and the filter 5 has a mesh size of 160-200. When using, place the filter bag containing coffee into the filter layer 7, assemble all parts of the extraction cup, and make sure the lid 1 is completely closed. Start the magnetic stirrer 6 to stir. After extraction is complete, remove the filter bag and pour out the coffee liquid.

[0023] Example 2 Green coffee beans were taken from the same batch to ensure experimental consistency. Before use, the green beans were stored at -20±1℃ to prevent moisture fluctuations and oxidation. The coffee roasting process was carried out in a ZAHPA-0805 intelligent coffee roaster, using a programmed temperature control system to set five roast levels: Light (R1), Light-medium (R2), Medium (R3), Medium-dark (R4), and Dark (R5). The corresponding parameters for each roast level are shown in Table 1. After roasting, the coffee beans were rapidly cooled to room temperature using air cooling, then sealed in airtight bags and stored at -20℃ for at least 12 hours to stabilize their flavor components. They were then allowed to warm to room temperature before grinding. All baked samples were uniformly ground to 700-900 μm, with a powder-to-water ratio of 1:10 and an extraction time of 8 h. Extraction was performed in the extraction vessel described in Example 1. Sensory evaluation was conducted by at least 10 experienced evaluators, with the evaluation time being less than or equal to 0.5 h. The list of sensory evaluation attributes is shown in Table 2, and the results are shown in Table 3. This result uses a scoring system of 1 and 0 as an example, but is not limited to this scoring format. 1 indicates that the attribute can be observed, and 0 indicates that the attribute cannot be observed. The sensory evaluation results are shown below. Figure 2 .

[0024] From Table 3 and Figure 2It can be seen that, in the two different scoring methods, the bitterness of cold brew coffee increases, the sweetness and aftertaste weakens as the roasting degree increases, and the liking of cold brew coffee decreases. Among them, the light roast sample (R1) has the highest liking.

[0025] Table 1. Parameters of coffee samples under different roasting programs

[0026] Note: Different letters in the same row indicate significant differences. p <0.05).

[0027] Table 2. List of Sensory Evaluation Attributes for Cold Brew Coffee

[0028] Table 3. Frequency of descriptive terms for cold brew coffee at different roasting levels.

[0029] Note: Bold p The value indicates significance ( p <0.05).

[0030] Example 3 Green coffee bean samples were taken from the same batch to ensure experimental consistency. Before use, the green beans were stored at −20±1℃ to prevent moisture fluctuations and oxidation. The coffee bean roasting process was carried out in a ZAHPA-0805 intelligent coffee roaster, with the roasting level set to light-medium roast (R2) using a programmed temperature control method; specific parameters are shown in Table 1. After roasting, the coffee beans were rapidly cooled to room temperature by air cooling and then sealed in airtight bags, stored at -20℃ for at least 12 hours to stabilize their flavor components.

[0031] Before grinding, the samples were removed and allowed to warm to room temperature. All baked samples were uniformly ground to 700-900 μm with a powder-to-water ratio of 1:10. Five extraction times were set (2, 4, 6, 8, and 10 h). Extraction was performed in the extraction vessel used in Example 1. Sensory evaluation was conducted by at least 10 experienced evaluators, ensuring the evaluation time was less than or equal to 0.5 h. The sensory evaluation results are shown below. Figure 3 The sensory evaluation results are shown in Table 4. This result uses a score of 1 and 0 as an example, but is not limited to this scoring form. 1 means that the attribute can be observed and 0 means that the attribute cannot be observed. The five extraction time treatment groups are denoted as T1-T5, and the corresponding times are T1 (2 h), T2 (4 h), T3 (6 h), T4 (8 h) and T5 (10 h) respectively.

[0032] From Table 4 and Figure 3It can be seen that, for samples with different extraction times, under two different scoring methods, the caramel flavor and aftertaste of cold brew coffee increased with the increase of extraction time, and the preference for cold brew coffee first decreased and then increased, with the 10-hour extraction (T5) having the highest preference.

[0033] Table 4. Frequency of descriptive terms for cold brew coffee at different extraction times.

[0034] Note: Bold p The value indicates significance ( p <0.05).

[0035] Example 4 Green coffee bean samples were taken from the same batch to ensure experimental consistency. Before use, the green beans were stored at −20±1℃ to prevent moisture fluctuations and oxidation. The coffee bean roasting process was carried out in a ZAHPA-0805 intelligent coffee roaster, with the roasting level set to light-medium roast (R2) using a programmed temperature control method; specific parameters are shown in Table 1. After roasting, the coffee beans were rapidly cooled to room temperature by air cooling and then sealed in airtight bags, stored at -20℃ for at least 12 hours to stabilize their flavor components.

[0036] Before grinding, the samples were removed and allowed to warm to room temperature. All baked samples were uniformly ground to 700-900 μm, and the extraction time was 8 h. Five powder-to-water ratios were set (1:12, 1:10, 1:8, 1:6, 1:4), and the samples were placed in the extraction vessel of Example 1 for extraction. Sensory evaluation was conducted by no fewer than 10 experienced evaluators, and the evaluation time must be less than or equal to 0.5 h. The sensory evaluation results are shown below. Figure 4 The sensory evaluation results are shown in Table 6. This result uses a score of 1 and 0 as an example, but is not limited to this scoring format. 1 means that the attribute can be observed and 0 means that the attribute cannot be observed. The different powder-to-water ratio treatment groups are denoted as W1-W5, which are W1 (1:12), W2 (1:10), W3 (1:8), W4 (1:6) and W5 (1:4) respectively.

[0037] From Table 5 and Figure 4 It can be seen that, for samples with different coffee-to-water ratios, in the two different scoring methods, as the coffee-to-water ratio increases, the bitterness of cold brew coffee increases and the liking decreases, with the 1:12 coffee-to-water ratio (W1) having the highest liking.

[0038] Table 5. Frequency of descriptive terms for cold brew coffee with different coffee-to-water ratios.

[0039] Note: Bold p The value indicates significance ( p <0.05).

[0040] Example 5 Green coffee bean samples were taken from the same batch to ensure experimental consistency. Before use, the green beans were stored at −20±1℃ to prevent moisture fluctuations and oxidation. The coffee bean roasting process was carried out in a ZAHPA-0805 intelligent coffee roaster, with the roasting level set to light-medium roast (R2) using a programmed temperature control method; specific parameters are shown in Table 1. After roasting, the coffee beans were rapidly cooled to room temperature by air cooling and then sealed in airtight bags, stored at -20℃ for at least 12 hours to stabilize their flavor components.

[0041] Before grinding, the samples were removed and allowed to warm to room temperature. The extraction time for all baked samples was uniformly set at 8 hours, with a powder-to-water ratio of 1:10. Five particle sizes (900μm-1100μm, 700μm-900μm, 500μm-700μm, 300μm-500μm, and 100μm-300μm) were placed in the extraction vessel of Example 1 for extraction. Sensory evaluation was conducted by no fewer than 10 experienced evaluators, and the evaluation time must be less than or equal to 0.5 hours. The sensory evaluation results are shown below. Figure 5 The sensory evaluation results are shown in Table 6. This result uses a score of 1 and 0 as an example, but is not limited to this scoring format. 1 means that the attribute can be observed, and 0 means that the attribute cannot be observed. Different particle size groups are denoted as G1-G5, which correspond to G1 (900-1100μm), G2 (700-900μm), G3 (500-700μm), G4 (300-500μm) and G5 (100-300μm), respectively.

[0042] From Table 6 and Figure 5 It can be seen that, for samples with different grinding particle sizes, under two different scoring methods, the fluctuations in the black, smoky, and sour tastes of cold brew coffee increased with the increase in particle size, and the liking fluctuated. Among them, 900-1100μm (G1) had the highest liking.

[0043] Table 6. Frequency of descriptive terms for cold brew coffee with different coffee-to-water ratios.

[0044] Note: Bold p The value indicates significance ( p <0.05).

[0045] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing flavor-optimized cold brew coffee, characterized in that, Includes the following steps: (1) The coffee beans are sampled, smelled, visually inspected and impurities and defects are determined in sequence to obtain pre-treated coffee beans; When sampling, take a sample of more than 300 g; During olfactory testing, the nose is placed close to the sample, and a deep breath is taken in. The odor is then identified and tested. If there is a foul or unusual odor, the test is rejected. During visual inspection, the sample is spread on a black plate under sunlight or artificial light to check the overall color and uniformity of the coffee beans. When identifying impurities and defects, refer to the defect diagram of green coffee in Appendix C of ISO 10470:2004 for judgment, select defective beans, and ensure that the overall defect rate is ≤10±0.5%; (2) Take 150±10 g of pretreated coffee beans and roast them at 216.85±0.88 ℃ for 300±15 s. After roasting, air cool the coffee beans to room temperature, then seal them in a sealed bag and store them at -20 ℃ for at least 12 h. (3) Grind and sieve the coffee beans, then put them into a filter bag and place it in the filter layer of the extraction cup. Add 10-12 times the weight of water to the coffee beans, and extract with magnetic stirring at 19±1 ℃ for 10 h. Filter to obtain flavor-optimized cold brew coffee.

2. The method for preparing flavor-optimized cold brew coffee as described in claim 1, characterized in that, In step (2), the coffee beans are roasted to the following color values: L*=30.35±0.59, a*=14.63±0.23, b*=20.83±0.

67.

3. The method for preparing flavor-optimized cold brew coffee as described in claim 1, characterized in that, In step (3), coffee beans stored at room temperature are ground directly, while frozen coffee beans are ground after being warmed to room temperature.

4. The method for preparing flavor-optimized cold brew coffee as described in claim 1, characterized in that, In step (3), the coffee beans are sieved through 15-mesh and 20-mesh sieves to retain 900-1100 μm coffee bean particles.

5. The method for preparing flavor-optimized cold brew coffee as described in claim 1, characterized in that, In step (3), magnetic stirring is performed at 200±50 r / min.

6. The method for preparing flavor-optimized cold brew coffee as described in claim 1, characterized in that, In step (3), the extraction cup includes a cup body, an outer temperature-sensitive shell, a detachable cup lid, a base, a motor and a battery, and a button. The cup body has an inner extraction layer, the top of which is threaded to the inside of the cup lid. The bottom of the cup body has a detachable filter layer, a filter screen and a magnetic stirrer are installed above the filter layer, and the magnetic stirrer is magnetically coupled to the motor. The thermochromic shell has a double-layer structure, with the bottom ends of the two shells closed to form a sealed interlayer, and a thermochromic material is placed inside the interlayer.

7. The method for preparing flavor-optimized cold brew coffee as described in claim 6, characterized in that, The temperature-sensitive outer shell and the extraction inner layer are made of food-grade pure aluminum, and the temperature-sensitive outer shell changes color at a water temperature of 19±1 ℃.

8. The method for preparing flavor-optimized cold brew coffee as described in claim 6, characterized in that, The height of the filter screen is one-third of the height of the inner extraction layer, and the filter screen size is 160-200 mesh.

9. The method for preparing flavor-optimized cold brew coffee as described in claim 6, characterized in that, The magnetic stirrer rotates at a speed of 100-600 r / min.

10. Flavor-optimized cold brew coffee prepared by the method of any one of claims 1-9.

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