Preparation method of alkaline craft beer

Abstract

The invention discloses a method for preparing alkaline craft beer, which comprises the following steps of: preparing raw materials, namely selecting barley malt with specific protein and starch contents, accurately crushing, pretreating by using hops with high alpha-acid content, performing reverse osmosis treatment and further purifying purified water, and drying food-grade sodium bicarbonate; the preparation method comprises the following steps: mixing barley malt and water in proportion, saccharifying, and filtering by a plate frame or a candle filter to obtain wort; adding humulus lupulus when wort is boiled, and adding sodium bicarbonate to adjust the pH value to 7.0-7.5 before the wort is boiled; carrying out rotary precipitation and cooling, and then adding activated yeast for fermentation; after fermentation, filtering by a diatomite or membrane filtering device, filling into a cleaned and disinfected container, pasteurizing, and cooling to obtain a finished product. By accurately controlling the raw materials and process parameters, the beer is mellow in taste, unique in flavor and suitable in alkalinity, meets the requirements of some consumers for alkaline drinks, and has certain market competitiveness.

Description

Technical Field

[0001] The invention relates to the technical field of beer brewing, and in particular to a method for preparing alkaline craft beer. Background Art

[0002] As a popular alcoholic beverage, beer is becoming increasingly diverse in variety and flavor. During the brewing process, traditional beer typically focuses on the selection of raw materials such as malt and hops, as well as the control of the fermentation process, to achieve a beer with a specific taste and flavor. However, most traditional beers are acidic, with a pH value typically around 4.0-4.5. For some people with excessive gastric acid secretion and sensitive stomachs, long-term consumption of acidic beer may increase the burden on the stomach and cause discomfort. Furthermore, from a health perspective, alkaline beverages help regulate the body's acid-base balance and have certain health benefits. For some consumers who pursue health and hope to regulate the body's acid-base balance, alkaline beer is more attractive.

[0003] Although there have been some attempts to adjust the pH of beer in the prior art, these efforts often suffer from complex preparation processes and unstable beer taste and quality. Therefore, developing a method for consistently producing alkaline craft beer with good taste and quality is of great practical significance. Summary of the Invention

[0004] The object of the present invention is to provide a method for preparing alkaline craft beer, by precisely controlling the selection of raw materials, preparation process parameters, etc., to prepare craft beer with a mellow taste, unique flavor and appropriate alkalinity.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions.

[0006] A method for preparing alkaline craft beer comprises the following steps:

[0007] Raw materials preparation:

[0008] Select high-quality barley malt with a protein content of 10%-12% and a starch content of 60%-65%, and grind it to a 20-40 mesh sieve; select Cascade hops with an alpha acid content of 5%-7%; use purified water treated with reverse osmosis, with the hardness of the water controlled at 50-100 mg / L as calcium carbonate and the pH adjusted to 6.5-7.0; prepare food-grade sodium bicarbonate with a purity of not less than 99%;

[0009] Saccharification:

[0010] Mix the crushed barley malt and water in a mass ratio of 1:3-1:4 and add it to the saccharification pot; first control the saccharification temperature at 62-65℃ for 30-40 minutes, then increase the temperature to 72-75℃ and maintain it for 10-15 minutes;

[0011] filter:

[0012] The saccharified mash is passed through a plate and frame filter or a candle filter for solid-liquid separation. The filtration speed is controlled so that the volume of the filtered mash per hour is 1 / 8-1 / 6 of the effective volume of the saccharification pot to obtain clarified wort.

[0013] boiled:

[0014] Pump the wort into the boiling kettle, add the prepared hops, and boil for 60-90 minutes; 10-15 minutes before the end of the boil, slowly add sodium bicarbonate while stirring at 50-80 rpm until the pH value of the wort is adjusted to 7.0-7.5;

[0015] Rotary sinking:

[0016] After boiling, quickly pump the wort into the rotary settling tank, control the speed of the rotary settling tank to 8-12 rpm, so that the hot coagulant settles, and the rotary settling time is 20-30 minutes;

[0017] cool down:

[0018] Use a plate heat exchanger to cool the wort to 18-22°C after settling. During the cooling process, control the flow of cooling water to keep the wort cooling rate at 1-2°C per minute.

[0019] Fermentation:

[0020] The cooled wort was pumped into the fermentation tank at a rate of 0.8-1.2×10 8 Activated brewer's yeast was added at an inoculum volume of 1000 ml / mL; the fermentation temperature was controlled at 10-15°C, and the temperature fluctuation range was adjusted within ±0.5°C by the temperature control system of the fermenter. The fermentation time was 7-10 days; during the fermentation process, the sugar content and alcohol content of the fermentation liquid were regularly tested, and the fermentation parameters were adjusted according to the test results;

[0021] Filtration and filling:

[0022] After fermentation, the beer is filtered using a diatomaceous earth filter or a membrane filter to remove yeast and other impurities to obtain clarified beer. The filtered beer is then bottled into cleaned and sterilized beer bottles or cans, with the liquid level error controlled within ±2mm during the filling process. The beer is then pasteurized at a temperature of 60-65°C for 20-30 minutes and rapidly cooled to room temperature to obtain the finished alkaline craft beer.

[0023] Furthermore, the degree of pulverization of the barley malt meets the following conditions: among the pulverized barley malt particles, fine powder with a particle size of less than 0.2 mm accounts for 15%-25%, coarse powder with a particle size of 0.2-1.0 mm accounts for 50%-70%, and particles with a particle size greater than 1.0 mm accounts for no more than 15%.

[0024] Furthermore, the Cascade hops are pretreated before use, specifically by placing the hops in a refrigerated environment at a temperature of 4-6° C. and a relative humidity of 60%-70% for 24-48 hours, then taking them out and crushing them in a crusher at a speed of 30-50 rpm into granules with a particle size of 1-3 mm for later use.

[0025] Furthermore, the pure water after reverse osmosis treatment is subjected to the following treatments before being added to the saccharification pot: residual chlorine and organic matter in the water are further removed through an activated carbon filter, and the filtration rate of the activated carbon filter is controlled at 8-12m / h; and then passed through a precision filter with a filtration accuracy of 0.1-0.5μm to remove tiny particulate impurities in the water.

[0026] Furthermore, the food-grade sodium bicarbonate is dried before being added to the boiled wort. The specific method is: placing the sodium bicarbonate in a vacuum drying oven and drying it for 2-4 hours at a temperature of 80-100° C. and a vacuum degree of -0.08-0.1 MPa to make its water content less than 0.5%.

[0027] Beneficial effects of the present invention:

[0028] 1. The present invention ensures the quality and stability of raw materials by precisely controlling the selection and processing of raw materials, such as the degree of crushing of barley malt, pretreatment of hops, further purification of purified water, and drying of sodium bicarbonate, laying the foundation for the preparation of high-quality alkaline craft beer.

[0029] 2. During the preparation process, the process parameters of each link such as saccharification, filtration, boiling, sedimentation, cooling, and fermentation are strictly controlled, so that the various components in the beer can be fully transformed and interact with each other, thus giving the beer a mellow taste and unique flavor.

[0030] 3. By adding food-grade sodium bicarbonate during the boiling process and precisely adjusting the pH value of the wort, we successfully prepared craft beer with suitable alkalinity, which meets the demand of some consumers for alkaline beverages and has certain market competitiveness. DETAILED DESCRIPTION

[0031] The scheme of the present invention is described in more detail and completely below.

[0032] (1) Example 1

[0033] Raw material preparation

[0034] Select high-quality barley malt with a protein content of 11% and a starch content of 62%, and grind it to pass a 30-mesh sieve. Among the ground barley malt particles, the fine powder with a particle size of less than 0.2mm accounts for 20%, the coarse powder with a particle size of 0.2-1.0mm accounts for 60%, and the particles with a particle size greater than 1.0mm account for 8%;

[0035] Cascade hops with an α-acid content of 6% were selected and refrigerated in an environment at a temperature of 5° C. and a relative humidity of 65% for 36 hours. The hops were then removed and crushed in a crusher at a speed of 40 rpm into granules with a particle size of 2 mm for later use.

[0036] Using pure water treated with reverse osmosis, the water hardness is controlled at 75mg / L (calculated as calcium carbonate) and the pH value is adjusted to 6.8. The water is further filtered through an activated carbon filter with a filtration rate of 10m / h to remove residual chlorine and organic matter. The water is then filtered through a precision filter with a filtration accuracy of 0.3μm.

[0037] Prepare food-grade sodium bicarbonate with a purity of 99.5%, place the sodium bicarbonate in a vacuum drying oven, and dry it for 3 hours at a temperature of 90° C. and a vacuum degree of -0.09 MPa to reduce its water content to less than 0.5%.

[0038] saccharification

[0039] Mix the crushed barley malt and water in a mass ratio of 1:3.5 and add it to the saccharification pot; control the saccharification temperature within the range of 63°C and maintain it for 35 minutes; then raise the temperature to 73°C and maintain it for 12 minutes.

[0040] filter

[0041] The saccharification mash is passed through a plate and frame filter for solid-liquid separation, and the filtration speed is controlled so that the volume of filtered mash per hour is 1 / 7 of the effective volume of the saccharification pot to obtain clarified wort.

[0042] boiled

[0043] Pump the wort into the boiling pot, add the prepared hops, and boil for 75 minutes; 12 minutes before the end of the boil, slowly add sodium bicarbonate while stirring at a stirring speed of 65 rpm until the pH value of the wort is adjusted to 7.2.

[0044] Rotary Sinking

[0045] After boiling, the wort was quickly pumped into the rotary settling tank, the speed of the rotary settling tank was controlled at 10 rpm, and the settling time was 25 minutes.

[0046] cool down

[0047] The wort after settling was cooled to 20°C using a plate heat exchanger. The flow of cooling water was controlled during the cooling process to keep the cooling rate of the wort at 1.5°C per minute.

[0048] Fermentation

[0049] The cooled wort was pumped into the fermentation tank at a rate of 1.0×10 8 Activated brewer's yeast was added at an inoculum rate of 1000 ng / mL; the fermentation temperature was controlled at 12°C, and the temperature fluctuation range was precisely adjusted within ±0.5°C through the temperature control system of the fermenter. The fermentation time was 8 days; during the fermentation process, the sugar content and alcohol content of the fermentation liquid were regularly tested, and the fermentation parameters were adjusted according to the test results.

[0050] Filtration and filling

[0051] After fermentation, the beer is filtered using a diatomaceous earth filter to obtain clarified beer; the filtered beer is filled into cleaned and sterilized beer bottles, and the beer liquid level error is controlled within ±2mm during the filling process; it is pasteurized at a temperature of 62°C for 25 minutes and then quickly cooled to room temperature to obtain the finished alkaline craft beer.

[0052] (II) Example 2

[0053] Raw material preparation

[0054] Select high-quality barley malt with a protein content of 10% and a starch content of 60%, and grind it to pass through a 20-mesh sieve. Among the ground barley malt particles, the fine powder with a particle size of less than 0.2mm accounts for 15%, the coarse powder with a particle size of 0.2-1.0mm accounts for 70%, and the particles with a particle size greater than 1.0mm account for 12%;

[0055] Cascade hops with an α-acid content of 5% were selected and refrigerated at a temperature of 4° C. and a relative humidity of 60% for 24 hours. The hops were then removed and crushed in a crusher at a speed of 30 rpm into granules with a particle size of 1 mm for later use.

[0056] Using pure water treated with reverse osmosis, the water hardness is controlled at 50mg / L (calculated as calcium carbonate) and the pH value is adjusted to 6.5. The water is further filtered through an activated carbon filter with a filtration rate of 8m / h to remove residual chlorine and organic matter. The water is then filtered through a precision filter with a filtration accuracy of 0.1μm.

[0057] Prepare food-grade sodium bicarbonate with a purity of 99%, place the sodium bicarbonate in a vacuum drying oven, and dry it for 2 hours at a temperature of 80° C. and a vacuum degree of -0.08 MPa to reduce its water content to less than 0.5%.

[0058] saccharification

[0059] Mix the crushed barley malt and water in a mass ratio of 1:3 and add it to the saccharification pot; control the saccharification temperature within the range of 62°C and maintain it for 30 minutes; then raise the temperature to 72°C and maintain it for 10 minutes.

[0060] filter

[0061] The saccharified mash is passed through a candle filter for solid-liquid separation, and the filtration speed is controlled so that the volume of filtered mash per hour is 1 / 8 of the effective volume of the saccharification pot to obtain clarified wort.

[0062] boiled

[0063] Pump the wort into the boiling pot, add the prepared hops, and boil for 60 minutes; 10 minutes before the end of boiling, slowly add sodium bicarbonate while stirring at a stirring speed of 50 rpm until the pH value of the wort is adjusted to 7.0.

[0064] Rotary Sinking

[0065] After boiling, the wort was quickly pumped into the rotary settling tank, and the speed of the rotary settling tank was controlled to 8 rpm and the settling time was 20 minutes.

[0066] cool down

[0067] The wort after settling is cooled to 18°C using a plate heat exchanger. The flow of cooling water is controlled during the cooling process to keep the cooling rate of the wort at 1°C per minute.

[0068] Fermentation

[0069] The cooled wort was pumped into the fermentation tank at a rate of 0.8×10 8 Activated brewer's yeast was added at an inoculum rate of 100 ml / mL; the fermentation temperature was controlled at 10°C, and the temperature fluctuation range was accurately adjusted within ±0.5°C through the temperature control system of the fermenter. The fermentation time was 7 days; during the fermentation process, the sugar content and alcohol content of the fermentation liquid were regularly tested, and the fermentation parameters were adjusted according to the test results.

[0070] Filtration and filling

[0071] After fermentation, the beer is filtered using a membrane filtration device to obtain clarified beer; the filtered beer is filled into cleaned and sterilized cans, and the beer liquid level error is controlled within ±2mm during the filling process; after pasteurization, the sterilization temperature is 60℃ and the sterilization time is 20 minutes. After sterilization, it is quickly cooled to room temperature to obtain the finished alkaline craft beer.

[0072] (III) Example 3

[0073] Raw material preparation

[0074] Select high-quality barley malt with a protein content of 12% and a starch content of 65%, and grind it to pass a 40-mesh sieve. Among the ground barley malt particles, the fine powder with a particle size of less than 0.2mm accounts for 25%, the coarse powder with a particle size of 0.2-1.0mm accounts for 50%, and the particles with a particle size greater than 1.0mm account for 15%;

[0075] Cascade hops with an α-acid content of 7% were selected and refrigerated in an environment at a temperature of 6° C. and a relative humidity of 70% for 48 hours. The hops were then removed and crushed in a crusher at a speed of 50 rpm into granules with a particle size of 3 mm for later use.

[0076] Using pure water treated with reverse osmosis, the water hardness is controlled at 100 mg / L (calculated as calcium carbonate) and the pH value is adjusted to 7.0. The water is further filtered through an activated carbon filter with a filtration rate of 12 m / h to remove residual chlorine and organic matter. The water is then filtered through a precision filter with a filtration accuracy of 0.5 μm.

[0077] Prepare food-grade sodium bicarbonate with a purity of 99.8%, place the sodium bicarbonate in a vacuum drying oven, and dry it for 4 hours at a temperature of 100° C. and a vacuum degree of -0.1 MPa to reduce its water content to less than 0.5%.

[0078] saccharification

[0079] Mix the crushed barley malt and water in a mass ratio of 1:4 and add it to the saccharification pot; control the saccharification temperature within the range of 65°C and maintain it for 40 minutes; then raise the temperature to 75°C and maintain it for 15 minutes.

[0080] filter

[0081] The saccharification mash is passed through a plate and frame filter for solid-liquid separation, and the filtration speed is controlled so that the volume of filtered mash per hour is 1 / 6 of the effective volume of the saccharification pot to obtain clarified wort.

[0082] boiled

[0083] Pump the wort into the boiling pot, add the prepared hops, and boil for 90 minutes; 15 minutes before the end of the boil, slowly add sodium bicarbonate while stirring at 80 rpm until the pH value of the wort is adjusted to 7.5.

[0084] Rotary Sinking

[0085] After boiling, the wort was quickly pumped into the rotary settling tank, and the speed of the rotary settling tank was controlled at 12 rpm and the settling time was 30 minutes.

[0086] cool down

[0087] The wort after settling was cooled to 22°C using a plate heat exchanger. The flow of cooling water was controlled during the cooling process to keep the cooling rate of the wort at 2°C per minute.

[0088] Fermentation

[0089] The cooled wort was pumped into the fermentation tank at a rate of 1.2×10 8 Activated brewer's yeast was added at an inoculum rate of 1000 ng / mL; the fermentation temperature was controlled at 15°C, and the temperature fluctuation range was precisely adjusted within ±0.5°C through the temperature control system of the fermenter. The fermentation time was 10 days; during the fermentation process, the sugar content and alcohol content of the fermentation liquid were regularly tested, and the fermentation parameters were adjusted according to the test results.

[0090] Filtration and filling

[0091] After fermentation, the beer is filtered using a diatomaceous earth filter to obtain clarified beer; the filtered beer is filled into cleaned and sterilized beer bottles, and the beer liquid level error is controlled within ±2mm during the filling process; it is pasteurized at a temperature of 65°C for 30 minutes and then quickly cooled to room temperature to obtain the finished alkaline craft beer.

[0092] Comparative Example

[0093] Traditional weakly acidic craft beer preparation method

[0094] 1. Raw material preparation

[0095] Barley malt: Select ordinary barley malt with a protein content of 8%-9% and a starch content of 55%-60%, and grind it until it passes through a 10-15 mesh sieve. The particle size after grinding is uneven, and there is no specific requirement for the particle size distribution;

[0096] Hops: Ordinary hops with an α-acid content of 3%-4% were used directly without pretreatment.

[0097] Water: Ordinary tap water was used, which was only treated by simple sand filtration. The water hardness was 120-150 mg / L (calculated as calcium carbonate) and the pH value was between 5.5-6.0. No precise adjustment was performed.

[0098] Yeast: Conventional beer yeast was used without activation treatment and was directly inoculated.

[0099] 2. Preparation steps

[0100] saccharification

[0101] Mix the crushed barley malt and water in a mass ratio of 1:2-1:2.5 and add it to the saccharification pot; control the saccharification temperature within the range of 58-60°C, maintain it for 20-25 minutes, then raise the temperature to 68-70°C and maintain it for 8-10 minutes.

[0102] filter

[0103] The saccharified mash is passed through a simple filter to separate the solid and liquid, and the filtration speed is not strictly controlled to obtain wort.

[0104] boiled

[0105] Pump the wort into the boil, add hops, and boil for 40-50 minutes without pH adjustment during the boil.

[0106] Rotary Sinking

[0107] After boiling, pump the wort into the rotary settling tank, control the speed of the rotary settling tank to 5-7 rpm, and the rotary settling time is 15-20 minutes.

[0108] cool down

[0109] Use natural cooling or simple heat exchange equipment to cool the wort to 25-28℃, and the cooling rate is not strictly controlled.

[0110] Fermentation

[0111] The cooled wort was pumped into the fermentation tank at a rate of 0.5-0.7×10 8 Brewer's yeast was added at an inoculum rate of 1000 cells / mL; the fermentation temperature was controlled at 16-18° C., the fermentation time was 5-7 days, and precise temperature control was not performed during the fermentation process.

[0112] Filtration and filling

[0113] After fermentation, the beer is filtered using simple filtering equipment to remove some impurities; the filtered beer is bottled into containers that have not been strictly cleaned and sterilized, and is not pasteurized or the pasteurization temperature and time are not strictly controlled.

[0114] 1. Sensory evaluation

[0115] 1. Sensory evaluation panel

[0116] A sensory evaluation panel of 20 people (10 men and 10 women) was selected. All panel members had experience in beer tasting, no history of oral diseases or allergies, and could accurately distinguish the flavor, taste and other characteristics of beer.

[0117] 2. Sensory Evaluation Form

[0118]

[0119] Evaluation method: Pour each sample into a transparent beer glass of the same size, number them and randomly present them to the evaluation team members. The team members independently evaluate according to the indicators in the table and give corresponding scores.

[0120] 3. Example of sensory evaluation results

[0121]

[0122] 2. Main physical and chemical index tests

[0123] 1. Test items

[0124] Alcohol content (% vol), original wort concentration (°P), pH value, total acidity (as lactic acid, g / L), carbon dioxide content (g / L) 2. Table of main physical and chemical indexes of the liquors of the examples and comparative examples

[0125]

[0126]

[0127] 3. Test Method

[0128] Alcohol content: measured by distillation method combined with alcohol meter;

[0129] Original wort concentration: measured using the density bottle method;

[0130] pH value: measured directly with a pH meter;

[0131] Total acid: determined by acid-base titration;

[0132] Carbon dioxide content: measured by the pressure reducer method.

[0133] 3. Bitterness (BU) Determination

[0134] 1. Determination method

[0135] The bittering substances (BU) in beer were determined by the iso-α-acid method. After the beer sample was appropriately diluted, an iso-α-acid standard solution was added. The absorbance was measured by a spectrophotometer, and the bittering substance content was calculated according to the standard curve.

[0136] 2. Bitterness (BU) determination table

[0137] Sample number Bitterness (BU) Example 1 25 Example 2 22 Example 3 28 Comparative Example 18

[0138] IV. Conclusion

[0139] 1. Sensory evaluation conclusion

[0140] From the sensory evaluation results, it can be seen that Examples 1, 2, and 3 are superior to the comparative example in appearance, aroma, taste, and overall flavor. Example 1 has the highest comprehensive score, indicating that it performs best in terms of color, clarity, aroma coordination, taste balance, and overall flavor uniqueness, and is more in line with the preferences of the evaluation panel members.

[0141] 2. Conclusions of physical and chemical indicators

[0142] The physical and chemical indicators of Examples 1, 2, and 3, such as alcohol content, original wort concentration, pH value, total acid and carbon dioxide content, are all within a reasonable range, and the pH values are all in the alkaline range (7.0-7.5), meeting the requirements of alkaline craft beer. The pH value of the comparative example is lower and weakly acidic, and other physical and chemical indicators are not as ideal as those of the examples.

[0143] 3. Conclusion on bitterness

[0144] The bittering substances in Examples 1, 2, and 3 have moderate contents of 25BU, 22BU, and 28BU, respectively, which can impart moderate bitterness to the beer and coordinate with other flavor components of the beer. The bittering substance content in the comparative example is relatively low, only 18BU, resulting in a thin taste and an uncoordinated flavor in the beer.

[0145] In summary, the preparation method of alkaline craft beer provided by the present invention (Examples 1, 2, and 3) successfully prepared craft beer with a mellow taste, unique flavor, and appropriate alkalinity by precisely controlling the selection of raw materials and preparation process parameters. It is superior to the control example in terms of sensory evaluation and physical and chemical indicators, and has significant advantages and market competitiveness.

[0146] 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 and improvements made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A method for preparing alkaline craft beer, characterized in that: The following steps are involved: Raw materials preparation: Select high-quality barley malt with a protein content of 10%-12% and a starch content of 60%-65%, and grind it to a 20-40 mesh sieve; select Cascade hops with an alpha acid content of 5%-7%; use purified water treated with reverse osmosis, with the hardness of the water controlled at 50-100 mg / L as calcium carbonate and the pH adjusted to 6.5-7.0; prepare food-grade sodium bicarbonate with a purity of not less than 99%; Saccharification: Mix the crushed barley malt and water in a mass ratio of 1:3-1:4 and add it to the saccharification pot; first control the saccharification temperature at 62-65℃ for 30-40 minutes, then increase the temperature to 72-75℃ and maintain it for 10-15 minutes; filter: The saccharified mash is passed through a plate and frame filter or a candle filter for solid-liquid separation. The filtration speed is controlled so that the volume of the filtered mash per hour is 1 / 8-1 / 6 of the effective volume of the saccharification pot to obtain clarified wort. boiled: Pump the wort into the boiling kettle, add the prepared hops, and boil for 60-90 minutes; 10-15 minutes before the end of the boil, slowly add sodium bicarbonate while stirring at 50-80 rpm until the pH value of the wort is adjusted to 7.0-7.5; Rotary sinking: After boiling, quickly pump the wort into the rotary settling tank, control the speed of the rotary settling tank to 8-12 rpm, so that the hot coagulant settles, and the rotary settling time is 20-30 minutes; cool down: Use a plate heat exchanger to cool the wort to 18-22°C after settling. During the cooling process, control the flow of cooling water to keep the wort cooling rate at 1-2°C per minute. Fermentation: The cooled wort was pumped into the fermentation tank at a rate of 0.8-1.2×10 8 Activated brewer's yeast was added at an inoculum volume of 1000 ml / mL; the fermentation temperature was controlled at 10-15°C, and the temperature fluctuation range was adjusted within ±0.5°C by the temperature control system of the fermenter. The fermentation time was 7-10 days; during the fermentation process, the sugar content and alcohol content of the fermentation liquid were regularly tested, and the fermentation parameters were adjusted according to the test results; Filtration and filling: After fermentation, the beer is filtered using a diatomaceous earth filter or a membrane filter to remove yeast and other impurities to obtain clarified beer. The filtered beer is then bottled into cleaned and sterilized beer bottles or cans, with the liquid level error controlled within ±2mm during the filling process. The beer is then pasteurized at a temperature of 60-65°C for 20-30 minutes and rapidly cooled to room temperature to obtain the finished alkaline craft beer.

2. The method for preparing alkaline craft beer according to claim 1, wherein: The degree of crushing of the barley malt meets the following conditions: among the crushed barley malt particles, the fine powder with a particle size of less than 0.2 mm accounts for 15%-25%, the coarse powder with a particle size of 0.2-1.0 mm accounts for 50%-70%, and the particles with a particle size greater than 1.0 mm account for no more than 15%.

3. The method for preparing alkaline craft beer according to claim 1, wherein: The Cascade hops are pretreated before use. The specific steps are: placing the hops in an environment with a temperature of 4-6°C and a relative humidity of 60%-70% for refrigeration for 24-48 hours, then taking them out and crushing them into particles with a particle size of 1-3 mm in a crusher at a rotation speed of 30-50 revolutions per minute for later use.

4. The method for preparing alkaline craft beer according to claim 1, wherein: The purified water after reverse osmosis treatment is subjected to the following treatments before being added to the saccharification pot: the residual chlorine and organic matter in the water are further removed by an activated carbon filter, and the filtration rate of the activated carbon filter is controlled at 8-12m / h; and then the water is passed through a precision filter with a filtration accuracy of 0.1-0.5μm to remove tiny particulate impurities in the water.

5. The method for preparing alkaline craft beer according to claim 1, wherein: The food-grade sodium bicarbonate is dried before being added to the boiled wort. The specific method is as follows: the sodium bicarbonate is placed in a vacuum drying oven and dried for 2-4 hours under the conditions of a temperature of 80-100° C. and a vacuum degree of -0.08-0.1 MPa, so that its water content is less than 0.5%.

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