Tibet low-alcohol highland barley wine and preparation method thereof

Abstract

The invention provides Tibet low-alcohol highland barley wine and a preparation method thereof, and belongs to the technical field of brewing processes. By providing a systematic and controllable preparation method, the stability and repeatability of highland barley wine production can be remarkably improved, and it is ensured that flavor and quality of products in different batches are highly consistent. The method is high in operability and easy to realize standardized production, so that the production efficiency is effectively improved, and the unique flavor characteristics and taste of the traditional highland barley wine are fully reserved. The implementation of the invention provides reliable technical support for modernization upgrading of the traditional highland barley wine industry, is beneficial to promoting the national characteristic product to realize the transformation from family workshop type production to standardized and branded production, and has positive significance for protecting and inheriting Tibetan diet culture and promoting regional economic development.

Description

Technical Field

[0001] This invention relates to the field of brewing technology, and in particular to a low-alcohol Tibetan barley wine and its preparation method. Background Technology

[0002] In traditional fermented alcoholic beverage production, grain-based brewing techniques have a long history, resulting in distinctive wines in various parts of the world. Examples include rice wine and rice wine made from rice, as well as certain regional fermented wines based on grains such as barley. The core of these products' production typically lies in utilizing natural or cultured microbial communities (such as molds, yeasts, and lactic acid bacteria) to saccharify the starch in the grains, thereby fermenting and producing alcohol and a series of flavor compounds.

[0003] However, many traditional brewing techniques rely heavily on generations of experience, involving multiple key control points in the production process, such as the pretreatment of raw materials, the degree of cooking, the control of fermentation temperature and time, and the amount of yeast or fermenting agent used. These steps are mostly adjusted based on the operator's sensory judgment and experience, lacking quantifiable and standardized process standards. This experience-driven production model easily leads to fluctuations in basic physicochemical indicators such as alcohol content, acidity, and sweetness between different batches or even between products from the same producer at different times, making it difficult to guarantee consistency in flavor and taste.

[0004] While the modern food industry has achieved a high degree of standardization and automation in the production of many bulk alcoholic beverages (such as beer and wine), for niche grain-fermented beverages with regional characteristics, unique raw materials, or traditional processes, achieving clear process parameters and stable and controllable production processes without losing their traditional flavor essence remains a common technical bottleneck in industrial upgrading and large-scale development. In particular, there is room for in-depth exploration and technological innovation in dealing with the processing characteristics of special raw materials, utilizing local microbial resources, and balancing traditional processes with modern quality control systems. Summary of the Invention

[0005] The purpose of this invention is to provide a low-alcohol Tibetan barley wine and its preparation method, which solves the problem that existing brewing processes are unable to achieve significant improvement in flavor and quality and stable output.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing low-alcohol barley wine, comprising the following steps: The barley raw materials are screened and cleaned. Soak the washed barley in water; The soaked barley is then steamed or boiled. The cooked barley is then spread out to cool. The cooled barley was mixed with a saccharification and fermentation agent and then fermented. After fermentation, the mash is soaked in water and subjected to solid-liquid separation to obtain the low-alcohol barley wine.

[0007] Preferably, the screening and cleaning process includes: controlling the moisture content of the barley raw material to be no higher than 13% and controlling the proportion of imperfect grains to be no higher than 10%.

[0008] Preferably, the soaking water temperature for the soaking treatment is 50℃~60℃, and the soaking time is 18 hours~30 hours; The pressure of the cooking process is 0.12 MPa to 0.18 MPa, and the cooking time is 1.5 hours to 2.5 hours.

[0009] Preferably, the cooling process involves cooling the barley to 17°C~26°C.

[0010] Preferably, the saccharification and fermentation agent comprises Tibetan local yeast and lactic acid bacteria; The amount of the saccharification and fermentation agent added is 0.02% to 0.05% of the total mass of the highland barley raw material.

[0011] Preferably, the fermentation temperature is 25℃~35℃ and the fermentation time is 44 hours~52 hours.

[0012] Preferably, the water extraction and solid-liquid separation process includes: adding water to the mash at a mass-to-volume ratio of water to barley raw material of 1.5:1 to 2.5:1 mL / g, extracting for 2.5 to 4.5 hours, and then filtering.

[0013] Preferably, the cooking process involves stirring once or multiple times; The cooling process is carried out under ventilated conditions.

[0014] Preferably, the fermentation process is carried out under sealed and heat-insulated conditions.

[0015] The present invention also provides a low-alcohol barley wine, which is prepared by the above method.

[0016] The beneficial effects of this invention are: This invention provides a systematic and controllable preparation method that significantly improves the stability and repeatability of highland barley wine production, ensuring a high degree of consistency in flavor and quality across different batches. This method is not only highly operable and easy to standardize, thus effectively improving production efficiency, but also fully preserves the unique flavor characteristics and taste of traditional highland barley wine. The implementation of this invention provides reliable technical support for the modernization and upgrading of the traditional highland barley wine industry, helping to promote the transformation of this ethnic specialty product from family workshop-style production to standardized and branded production. It also has positive significance for protecting and inheriting Tibetan food culture and promoting regional economic development. Attached Figure Description

[0017] Figure 1 This is a diagram showing the distribution of volatile flavor compounds. Detailed Implementation

[0018] This invention provides a method for preparing low-alcohol barley wine. The method, through meticulous pretreatment of raw materials, precise control of key processes, and the application of specific fermentation agents, aims to obtain a product with harmonious flavor and stable quality.

[0019] First, the barley raw material undergoes screening and cleaning. Barley, also known as naked barley, is a major grain crop in high-altitude regions, and its grains are rich in starch, protein, β-glucan, and various trace elements. The screening and cleaning process aims to remove impurities, dust, and substandard grains from the raw material, which is a fundamental step in ensuring the purity and uniformity of the brewing raw material. Specifically, this process includes controlling the moisture content of the barley raw material, preferably not exceeding 13%, and more preferably not exceeding 12%; at the same time, controlling the proportion of imperfect grains (including insect-eaten grains, broken grains, and diseased grains), preferably not exceeding 10%, and more preferably not exceeding 8%. Moisture content and grain integrity directly affect the uniformity and efficiency of subsequent soaking, water absorption, cooking, gelatinization, and fermentation.

[0020] Next, the washed barley is soaked. The purpose of soaking is to allow the barley grains to fully absorb water, softening the tissue and facilitating starch gelatinization during subsequent cooking. The soaking water temperature is a key parameter, preferably 50°C to 60°C, more preferably 52°C to 58°C, for example, about 55°C. Soaking under these warm water conditions promotes water penetration while preventing excessive microbial growth. The soaking time is preferably 18 to 30 hours, more preferably 20 to 28 hours, for example, about 24 hours. This process ensures that the barley reaches a suitable moisture content.

[0021] Next, the soaked barley is steamed. Steaming is a necessary step to gelatinize the barley starch, and the degree of gelatinization directly affects the efficiency of saccharification and fermentation. The steaming process is carried out under a certain pressure, preferably in the range of 0.12 MPa to 0.18 MPa, more preferably 0.13 MPa to 0.17 MPa, for example, about 0.15 MPa. Steaming under this pressure can effectively improve thermal efficiency, allowing the barley to cook thoroughly in a shorter time. The steaming time is preferably 1.5 hours to 2.5 hours, more preferably 1.8 hours to 2.2 hours, for example, about 2 hours. The goal of steaming is to make the barley thoroughly cooked and cracked, achieving a state of good gelatinization but not excessive softness. To ensure uniform heating and avoid localized undercooking or excessive gelatinization, the barley can be stirred once or multiple times during the steaming process.

[0022] After steaming, the barley is cooled by spreading it out. This step aims to rapidly lower the material's temperature to a range suitable for microbial (saccharification and fermentation) activity, preventing damage to the active ingredients in the fermentation agent from high temperatures. The cooling process preferably cools the barley to 17°C to 26°C, more preferably 19°C to 24°C. This temperature range takes into account operability under different ambient temperatures (such as summer and winter), ensuring the consistency and suitability of the inoculation temperature. The cooling process is usually carried out under ventilated conditions to accelerate heat dissipation.

[0023] Subsequently, the cooled barley is mixed with a saccharifying and fermenting agent and fermented. The saccharifying and fermenting agent is the core component that initiates and dominates the fermentation process, and its composition directly affects the flavor and physicochemical properties of the product. In this invention, the saccharifying and fermenting agent contains yeast and lactic acid bacteria originating from Tibet. These microorganisms are adapted to the high-altitude environment. During fermentation, the yeast is mainly responsible for converting sugars into alcohol and producing various flavor substances such as alcohols and esters, while the lactic acid bacteria participate in acid production, helping to regulate the pH value of the fermentation system, inhibiting unwanted bacteria, and contributing a unique sour taste and mellow flavor. The amount of the saccharifying and fermenting agent added relative to the total mass of the barley raw material is preferably 0.02% to 0.05%, more preferably 0.025% to 0.04%, for example, about 0.03%. The amount added must be appropriate; too much may lead to excessive acidity or off-flavors, while too little may result in insufficient saccharification and fermentation.

[0024] The fermentation process is carried out at a specific temperature and time. The fermentation temperature is preferably controlled between 25°C and 35°C, more preferably between 27°C and 33°C, for example, about 28-30°C. The fermentation duration is preferably 44 to 52 hours, more preferably 46 to 50 hours, for example, about 48 hours. This combination of temperature and time range is beneficial to the orderly metabolism of the specific microbial community and the coordinated generation of flavor compounds. The fermentation process is preferably carried out under sealed and insulated conditions to maintain a stable microenvironment, prevent contamination by other microorganisms, and reduce the loss of flavor compounds through volatilization.

[0025] After fermentation, the resulting mash is subjected to water extraction and solid-liquid separation to extract the alcohol. In the water extraction process, the mass-to-volume ratio of water to barley raw material (water:raw material) is preferably 1.5:1 to 2.5:1 mL / g, more preferably 1.8:1 to 2.2:1 mL / g, for example, about 2:1 mL / g. The extraction time is preferably 2.5 to 4.5 hours, more preferably 3.0 to 4.0 hours, for example, about 3-4 hours. After extraction, a clear or slightly turbid alcohol is obtained through conventional solid-liquid separation methods such as filtration and pressing, thus obtaining the low-alcohol barley wine. The extraction water used is preferably purified water or water that meets drinking water standards to avoid introducing impurities or off-flavors.

[0026] This invention also provides a low-alcohol barley wine, which is prepared by the method described under any one or more of the above-mentioned preferred conditions. Through the systematic and parameter-controllable preparation method, the resulting product retains the typical style of traditional barley wine while exhibiting harmonious flavor and stable quality.

[0027] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0028] Materials used in the examples: Barley (unhulled), Tibetan yeast (from Qushui County, Lhasa, containing local Tibetan yeast and lactic acid bacteria), and purified water.

[0029] Example 1 Selection and cleaning of highland barley High-quality, plump highland barley grains are selected and repeatedly rinsed with clean water to remove damaged grains, insect-damaged grains, impurities, and dust. In accordance with national standards and relevant industry specifications, the following indicators are strictly controlled when selecting highland barley raw materials: moisture content should be controlled to be less than or equal to 13% (tested by drying method or rapid moisture analyzer); bulk density should not be less than 710 g / L (measured by bulk density meter); the proportion of imperfect grains should be ≤6%~10% according to different grades (manual screening or image recognition detection); pesticide residues must meet the GB2763-2021 standard (GC-MS or LC-MS detection); heavy metal content must meet the limits of GB 2762-2017 (e.g., lead ≤0.2 mg / kg, cadmium ≤0.1 mg / kg, detected by AAS or ICP-MS); impurity content must be ≤1%; and the barley must maintain normal color and odor, without any moldy, sour, or other abnormalities.

[0030] Barley soaking and steaming Soak the washed barley in 55℃ warm water for 24 hours. This allows the barley to fully absorb water, ensuring it cooks thoroughly and gelatinizes well during steaming. After soaking, place the barley in a stainless steel steamer for 2 hours at an optimal pressure of 0.15MPa, ensuring the barley is cooked through and cracks but not overly soft. Stir once during steaming to ensure even heating.

[0031] Cool Spread the steamed barley on a clean tray or cloth to cool. Ensure good ventilation during the cooling process so that the barley cools down to the appropriate temperature for adding koji as quickly as possible. Fermentation should be carried out at 18±1℃ in summer and 21~25℃ in winter.

[0032] Add amount of koji When the barley has cooled to a suitable temperature, sprinkle in the yeast starter and stir thoroughly to ensure the yeast and barley are fully mixed. The amount of yeast starter added is 0.03% of the weight of the raw materials. Adding too much yeast starter will result in excessively high acidity in the wine, while adding too little will reduce the saccharification power of the mold, decrease the fermentation effect, and affect the flavor of the barley wine.

[0033] Fermentation After adding the Tibetan yeast, place the barley into a fermentation container, insert a thermometer, seal it, and cover it with a cotton quilt for insulated fermentation. The starch in the barley begins to gradually convert into sugars under the action of enzymes in the yeast. During fermentation, the temperature should be between 25-35℃, and the fermentation time is 48 hours. The fermentation process should be checked regularly to observe whether the temperature is normal and whether the barley has an alcoholic aroma.

[0034] Soak in water Add purified water at a water-to-grain ratio of 2:1 (ml:kg) to the fermented mash and soak the mash for 3-4 hours. Avoid using water containing impurities, off-odors, or excessive microorganisms, otherwise it will affect the quality and taste of the highland barley wine.

[0035] Filtering and extracting wine Prepare a clean, well-sealed container of suitable volume to receive the filtered barley wine. Slowly pour the soaked mash (with water, etc.) into the filtering device. Control the flow rate during pouring to avoid insufficient filtration and impurities entering the wine.

[0036] Comparative Example 1 The only difference from Example 1 is that the amount of yeast added is replaced with 0.1% of the weight of the raw materials. Fermentation is carried out at a constant temperature of 28°C for 24 hours, and then naturally cooled to the ambient temperature (about 20°C) to continue fermentation for a total of 120 hours (5 days).

[0037] Comparative Example 2 The only difference from Example 1 is that the yeast is replaced with a conventional commercially available product: light-aroma daqu (the main strains of which are Aspergillus oryzae and yeast), and the amount added is 0.05% of the weight of the raw materials.

[0038] Experimental Example Based on the process in Example 1, the following experiments were conducted: Extraction of volatile flavor compounds: Sample pretreatment: Take a certain volume of 800 mL of traditional highland barley wine sample into a 2500 mL round-bottom flask.

[0039] Instrument Assembly and Parameter Settings: Securely mount the flask containing the mixed sample onto the rotary evaporator and connect the corresponding receiving flask. Turn on the condensation circulation system, set the water bath temperature to 90℃, and set the rotation speed to a medium intensity of 120 rpm to ensure that the sample forms a uniform liquid film inside the flask, increasing the evaporation area.

[0040] For the distillation extraction process, start the rotating apparatus and, once it is running smoothly, slowly apply a vacuum, gradually reducing the system pressure to a suitable range (e.g., 300-400 mbar). Closely observe the distillation process; you will see volatile components and solvent condense in the condenser and drip into the receiving flask. Continue distilling until the distillation rate decreases significantly, indicating that most of the solvent has evaporated. Slowly release the vacuum and turn off the rotating apparatus and heating.

[0041] Post-processing and concentration of the extract: Carefully remove the receiving bottle and transfer the collected extract to a stoppered centrifuge tube. Store at 5°C in the dark for analysis.

[0042] Flavor compound analysis Based on the analysis results of gas chromatography-mass spectrometry (GC-MS), a total of 151 volatile compounds were identified in five distilled samples, covering multiple categories such as alcohols, aldehydes, ketones, acids, esters, alkenes, alkanes, heterocyclic compounds and aromatic hydrocarbons, as shown in Table 1.

[0043] Table 1. Identification results of flavor substances in traditional highland barley wine

[0044] Alcohols were among the most abundant and abundant volatile components in this sample, with 38 identified. Ethanol (serial number 2) had the highest content among all distilled samples, reaching 265.826 mg / mL in distillation 5, imparting a pronounced alcoholic and pungent taste. Other important alcohols, such as n-propanol, isobutanol, n-hexanol, and n-octanol, all possessed fruity, sweet, or citrus aromas, playing a crucial role in the overall sweetness and fruitiness of the flavor. Furthermore, some alcohols with distinctive flavors, such as linalool (floral and citrus), menthol (mint), and geraniol (rose), although not detected in some samples, were present in significant amounts in specific distillation batches, demonstrating the significant impact of the distillation process on flavor composition.

[0045] Eight aldehyde compounds were identified, among which nonanal, benzaldehyde, and phenylacetaldehyde were detected in multiple samples, contributing to the fatty, almond, and floral aromas. Neroli and citral (numbers 43 and 44) ​​have strong lemon and citrus aromas. Although they were only detected in certain batches, their high flavor intensity plays an important role in enhancing the overall flavor.

[0046] Seven ketone compounds were identified, with 2-octanone (cheesy aroma) and acetophenone (floral and fruity aroma) being the main ones. D-carvone (serial number 50) was detected only in distillation 3, imparting minty and citrus flavors to the sample, demonstrating the uniqueness of this batch in terms of ketone flavor.

[0047] Seven acidic compounds were identified, primarily acetic acid, isobutyric acid, nonanoic acid, and decanoic acid, contributing to the sour, cheese, and fatty flavors. These acids significantly influence the body and complexity of the wine. Twenty ester compounds were identified, key components for fruity and floral aromas. Ethyl phenylethyl (honey and floral aromas), γ-nonanolide (coconut and cream aromas), and ethyl palmitate (fatty and fruity aromas) were detected in multiple samples, indicating significant stability of ester flavors. Olefins were the most numerous (61 in total), contributing a complex and diverse range of flavors, primarily including citrus, pine, resinous, and fatty notes. D-limonene, β-myrcene, and cedrene were present in high concentrations in many samples, especially in distillation batch 3, where the variety and content of olefins were significantly higher than in other batches, indicating a richer terpene flavor profile in this batch. Alkanes were fewer in number (6 in total), contributing relatively less flavor, primarily exhibiting fatty and grassy notes.

[0048] 2-Pentylfuran (beany flavor) was detected in trace amounts in multiple samples, possibly originating from raw materials or the fermentation process. Aromatic hydrocarbons such as 4-ethyl-2-methoxyphenol (smoky flavor) and 2,4-di-tert-butylphenol (smoky flavor) were present in higher concentrations in some samples, especially the latter in distillation 3, which reached 43.367 mg / mL, significantly enhancing the smoky and herbal flavor of the sample.

[0049] This experiment systematically analyzed the volatile components in five distilled samples using GC-MS technology, identifying a total of 151 compounds covering a variety of flavor characteristics. Figure 1 This section describes the distribution of volatile flavor compounds. Fruity and floral aromas are the most prominent flavor categories, with the citrus and floral subcategories containing the richest number of compounds, including key contributors such as D-limonene, linalool, and farnesol, which together form the product's fresh and pleasant main aroma base. Vegetarian notes (encompassing woody, grassy, ​​and resinous aromas) are another important dimension, with terpenes such as caryophyllene and alfalfaene providing a complex background of herbal and earthy notes. While fatty and creamy aromas have fewer compounds, their long-chain fatty acids and esters (such as decanoic acid and ethyl palmitate) play a crucial role in supporting the overall richness and persistence of the flavor. Overall, this flavor spectrum is centered on terpenes and esters, exhibiting complex layers and a balanced distribution of various flavor attributes, collectively shaping its unique and harmonious sensory characteristics.

[0050] Sensory evaluation experiments were conducted on the products from Example 1, Comparative Example 1, and Comparative Example 2: Ten sensory evaluators (5 men and 5 women, aged 25-50) were selected and trained. All had experience in wine tasting and were familiar with and had received training in basic flavor descriptions for highland barley wine. They were prohibited from eating spicy or irritating foods one hour before the evaluation.

[0051] Sample preparation The low-alcohol barley wines prepared in Example 1, Comparative Example 1, and Comparative Example 2 were all refrigerated and stored for 12 hours under the same conditions (4°C).

[0052] The three samples were randomly numbered A, B, and C, and blindly tested by the evaluators.

[0053] Using a standard tasting glass, pour approximately 30 mL of wine sample into each glass and let it stand at room temperature for 10 minutes to equilibrate. Provide purified water and unsalted crackers for rinsing your mouth.

[0054] Evaluation process: The evaluation consists of two independent stages: Descriptive analysis allows tasters to freely describe the appearance, aroma, taste, and flavor characteristics of each sample, and to record any unpleasant sensory attributes.

[0055] Quantitative scoring: Evaluators score each sample's various indicators according to the scoring criteria in Table 2 below (1-9 points, the higher the score, the better the quality).

[0056] Table 2 Sensory Evaluation Scoring Criteria

[0057] Note: Final score = weighted sum of scores for each item.

[0058] Sensory evaluation results Summary of descriptive analysis results: Sample A (Example 1): The tasters generally described it as having a "clear color", "a fresh citrus aroma and a light floral fragrance", "a smooth taste, a balance of sweet and sour, a slight sweetness of rice cake and the aroma of barley grains, a refreshing taste and a clean aftertaste".

[0059] Sample B (Comparative Example 1): Most tasters pointed out that its "aroma is slightly dull and has a more obvious sour taste", "the sour taste is more pungent after the first bite, which masks other flavors", and "there is a slight bitterness in the end, and the taste is not well-balanced".

[0060] Sample C (Comparative Example 2): The evaluations were quite diverse, but the negative descriptions were concentrated, such as "It has an unfamiliar smell, similar to certain cooked food or herbs, which is not the feeling of traditional highland barley wine", "The aroma and taste are somewhat separated, the taste is a bit 'strange' and not very acceptable", and "It lacks the expected freshness".

[0061] The quantitative scoring results are shown in Table 3 below: Table 3 Quantitative scoring results (mean score ± standard deviation)

[0062] The results showed that the sample provided in Example 1 of this invention achieved the highest scores in aroma, taste and flavor, and overall acceptability, with a significantly higher total score. Its sensory characteristics were characterized by a pure and harmonious aroma, a balanced and refreshing taste, and a typical and pleasant flavor, verifying the effectiveness of the combination of process parameters (specific amount of added yeast, fermentation temperature and time) in shaping and stabilizing the ideal sensory quality of highland barley wine.

[0063] As demonstrated by the above embodiments, this invention provides a method for preparing low-alcohol barley wine with clearly defined process parameters and a controllable production process, resulting in a product with excellent flavor. This method enables the stable reproduction of the core brewing steps of barley wine, exhibiting particularly good repeatability in the control of key process points. The barley wine product obtained using this method has basic physicochemical indicators within a controllable range, and modern analytical methods can detect a rich and diverse composition of volatile flavor compounds, which collectively constitute the typical flavor characteristics of the product. Different batches of the product show consistency in the main flavor framework. The method of this invention lays a practical foundation for the systematic study of the relationship between process and quality, and for achieving the stable and standardized production of barley wine.

[0064] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing low-alcohol barley wine, characterized in that, Includes the following steps: The barley raw materials are screened and cleaned. Soak the washed barley in water; The soaked barley is then steamed or boiled. The cooked barley is then spread out to cool. The cooled barley was mixed with a saccharification and fermentation agent and then fermented. After fermentation, the mash is soaked in water and subjected to solid-liquid separation to obtain the low-alcohol barley wine.

2. The method according to claim 1, characterized in that, The screening and cleaning process includes: controlling the moisture content of the barley raw material to be no higher than 13% and controlling the proportion of imperfect grains to be no higher than 10%.

3. The method according to claim 1, characterized in that, The soaking water temperature for the soaking treatment is 50℃~60℃, and the soaking time is 18 hours~30 hours; The pressure of the cooking process is 0.12 MPa to 0.18 MPa, and the cooking time is 1.5 hours to 2.5 hours.

4. The method according to claim 1, characterized in that, The cooling process involves cooling the barley to 17°C~26°C.

5. The method according to claim 1, characterized in that, The saccharification and fermentation agent contains local Tibetan yeast and lactic acid bacteria; The amount of the saccharification and fermentation agent added is 0.02% to 0.05% of the total mass of the highland barley raw material.

6. The method according to claim 5, characterized in that, The fermentation process is carried out at a temperature of 25℃ to 35℃ for a duration of 44 to 52 hours.

7. The method according to claim 1, characterized in that, The water extraction and solid-liquid separation process includes: adding water to the mash at a mass-to-volume ratio of water to barley raw material of 1.5:1 to 2.5:1 mL / g, extracting for 2.5 to 4.5 hours, and then filtering.

8. The method according to claim 1, characterized in that, The cooking process involves stirring once or multiple times. The cooling process is carried out under ventilated conditions.

9. The method according to claim 1, characterized in that, The fermentation process is carried out under sealed and heat-insulated conditions.

10. A low-alcohol barley wine, prepared by the method according to any one of claims 1 to 9.

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