Lactic acid bacteria amplification culture method, sour wort production method, beer production method and obtained beer

Abstract

The invention discloses a lactic acid bacteria amplification culture method, a sour wort production method, a beer production method and the obtained beer, the lactic acid bacteria amplification culture method comprises the following steps: adding saccharified wort into a culture flask, inoculating lactic acid bacteria to obtain a primary culture solution with the pH value of less than 4.0; s2, saccharified wort is taken and added into a Karl tank, the primary culture solution is added, and a secondary culture solution with the pH smaller than 4.0 is obtained; s3, taking saccharified wort, adding water for dilution, adding the diluted wort into a first-stage culture tank, and adding a second-stage culture solution to obtain a third-stage culture solution with the pH value of less than 4.0; s4, taking saccharified wort, adding water for dilution, adding the diluted wort into a second-stage culture tank, and adding the third-stage culture solution to obtain a fourth-stage culture solution with the pH value of less than 4.0; and S5, taking the saccharified wort, adding water for dilution, adding the diluted wort into a third-stage culture tank, and adding a fourth-stage culture solution to obtain a fermentation solution with the pH value of less than 4.0. The sour wort obtained by the invention is used for adjusting the pH value in beer brewing, and does not bring green and astringent taste to beer.

Description

Technical Field

[0001] The present invention relates to the technical field of food production, and specifically relates to a method for the enlarged cultivation of lactic acid bacteria. The fermentation broth obtained by using this method is used for the production of acid wort, and the acid wort produced is used for the production of beer and the obtained beer. Background Art

[0002] Beer is one of the oldest alcoholic beverages of mankind and is the third most consumed beverage in the world after water and tea. The ethanol content in beer is low, which can promote blood circulation and has medicinal effects such as strengthening the heart, stomach, diuresis, and analgesia. At the same time, beer contains rich nutritional components such as protein, carbohydrates, vitamins, and minerals, and has a good taste, which is deeply loved by consumers.

[0003] The brewing water of beer contains more bicarbonate ions, carbonate ions, and hydroxide ions. Moreover, when the quality of the malt used is poor and the content of acidic salts is too low, it is difficult to make the malt mash reach the optimal pH value. At this time, the method of adding acid is often used for improvement. In China, food-grade phosphoric acid and lactic acid are mainly used to adjust the pH value. However, too much phosphorus will cause premature aging of yeast; lactic acid is a medium weak acid. Lactic acid can make the wine body plump and will not make the pH value drop too low. However, using too much domestic lactic acid will bring astringent taste to beer; although imported lactic acid has a better taste, its price is expensive.

[0004] This application aims to obtain a pH regulator containing lactic acid to solve the above technical problems. Summary of the Invention

[0005] In view of the above-mentioned defects of the prior art, the present invention provides a method for the enlarged cultivation of lactic acid bacteria. The lactic acid obtained by this method will not bring astringent taste to beer; for this reason, the present invention also provides a method for the production of acid wort; in addition, the present invention also provides a method for the production of beer containing the above acid wort and the beer produced by using this method.

[0006] In the first aspect of the present invention, a method for the enlarged cultivation of lactic acid bacteria is provided, including the following steps:

[0007] S1. Take the saccharified wort and add it to a culture flask, cool it to 40 - 48 °C, inoculate lactic acid bacteria into the culture flask to obtain a primary culture solution with pH < 4.0, and the sugar content of the wort is 12 - 18 °P;

[0008] S2. First enlarged cultivation:

[0009] Take the saccharified wort and add it to a Carlsberg flask, cool it to 40 - 48 °C, add the primary culture solution to obtain a secondary culture solution with pH < 4.0, and the volume ratio of the Carlsberg flask to the culture flask is (20 - 250):1;

[0010] S3. Second-stage expansion culture:

[0011] Take the saccharified wort, dilute it with water and add it to the first-stage culture tank, cool it to 40-48 °C, add the second-stage culture solution to obtain a third-stage culture solution with pH < 4.0. The volume ratio of the first-stage culture tank to the Carlsberg flask is (8-50):1;

[0012] S4. Third-stage expansion culture:

[0013] Take the saccharified wort, dilute it with water and add it to the second-stage culture tank, cool it to 40-48 °C, add the third-stage culture solution to obtain a fourth-stage culture solution with pH < 4.0. The volume ratio of the second-stage culture tank to the first-stage culture tank is (2-10):1;

[0014] S5. Fourth-stage expansion culture:

[0015] Take the saccharified wort, dilute it with water and add it to the third-stage culture tank, cool it to 40-48 °C, add the fourth-stage culture solution to obtain a fermentation broth with pH < 4.0. The volume ratio of the third-stage culture tank to the second-stage culture tank is (2.5-10):1.

[0016] As a preferred embodiment, in step S1, the volume ratio of the wort to the lactic acid bacteria is (97-98):(2-3), and the volume percentage of the wort in the culture bottle is 97%-98%.

[0017] As a preferred embodiment, the addition amount of lactic acid bacteria in step S1 is 2.0×10 7 CFU / mL (add 2.0×10 7 CFU of lactic acid bacteria per milliliter of wort).

[0018] As a preferred embodiment, in step S2, the volume percentage of the wort in the Carlsberg flask is 95%-99%.

[0019] As a preferred embodiment, in step S3, the volume percentage of the wort in the first-stage culture tank is 50%-55%, and the volume percentage of the added water in the first-stage culture tank is 10%-15%.

[0020] As a preferred embodiment, in step S4, the volume percentage of the wort in the second-stage culture tank is 50%-55%, and the volume percentage of the added water in the second-stage culture tank is 10%-15%.

[0021] As a preferred embodiment, in step S5, the volume percentage of the wort in the third-stage culture tank is 50%-55%, and the volume percentage of the added water in the third-stage culture tank is 10%-15%.

[0022] In steps S1, S2, S3, S4, and S5, control the wort pH < 4 so that the wort acidity > 1%, which can be used as a pH regulator in the subsequent beer production process.

[0023] As a preferred embodiment, it further includes the step of sterilizing the culture flask, Carlsberg flask, primary culture tank, secondary culture tank, and tertiary culture tank.

[0024] Among them, the saccharified wort is the wort obtained after the saccharification step of the raw materials for beer production.

[0025] The raw materials for beer production include malt, rice, and corn.

[0026] As a preferred embodiment, the method for preparing the wort is as follows:

[0027] S1. Take malt, rice, and water, and the weight ratio of malt, rice, and water is 22:12:66;

[0028] S2. Crush the malt and rice;

[0029] S3. Add the crushed rice powder and water to the mash kettle, boil to obtain mash;

[0030] S4. Add the crushed malt powder and water to the saccharification kettle, and add calcium sulfate;

[0031] S5. Transfer the mash in the mash kettle to the saccharification kettle, filter to obtain wort with a sugar content of 12 - 18 °P.

[0032] As a preferred embodiment, the boiling time in step S3 is 10 minutes.

[0033] As a preferred embodiment, after adding calcium sulfate in step S4, it further includes the step of resting at 44 °C for 10 minutes.

[0034] As a preferred embodiment, step S5 includes the following:

[0035] S51. Transfer the mash in the mash kettle to the saccharification kettle;

[0036] S52. Raise the temperature to 66 °C, hold for 20 min, then raise the temperature to 74 °C to obtain wort mash;

[0037] S53. Filter the wort mash to obtain wort with a sugar content of 12 - 18 °P.

[0038] As a preferred embodiment, the culture temperature in steps S1 - S5 is 46 °C.

[0039] As a preferred embodiment, at the end of each step, the system pH is controlled at 3.6.

[0040] The second aspect of the present invention provides a method for producing sour wort, comprising the following steps:

[0041] S1. Take the saccharified wort and the fermentation broth obtained by the above-mentioned lactic acid bacteria enlarged culture method, and add them into a culture tank. The volume ratio of the wort to the fermentation broth is (3.5 - 4.5):(0.5 - 1.5);

[0042] S2. Ferment at 40 - 48 °C to obtain sour wort with a pH of 3 - 4.

[0043] As a preferred embodiment, the sugar content of the saccharified wort is 12 - 18 °P.

[0044] As a more preferred embodiment, the fermentation temperature of the saccharified wort is 46 °C, and the sugar content of the saccharified wort is 14 °P.

[0045] The third aspect of the present invention provides a method for producing beer, comprising the following steps:

[0046] S1. Add the saccharified wort into a boiling pot, add hops during the boiling process, and add the above-mentioned sour wort before the start of boiling. The addition amount of the sour wort accounts for 1.0% - 1.5% of the total volume of the wort, and the addition amount of the hops accounts for 0.04% - 0.05% of the total volume of the wort. The system pH is 5.2 - 5.3;

[0047] S2. Filter and ferment to obtain beer.

[0048] As a preferred embodiment, add the above-mentioned sour wort 5 minutes before the start of boiling.

[0049] Adding the sour wort 5 minutes before the start of boiling allows the sour wort to fully react with the bitter components in the hops, making the bitterness cleaner and improving the bitterness cleanliness better.

[0050] By controlling the system pH to be 5.2 - 5.3 after adding the sour wort, the pH > 4.3 after fermentation, which will not bring an obvious astringent feeling to the system, and what is obtained after fermentation is beer rather than sour beer.

[0051] As a preferred embodiment, yeast is added in step S2, and the yeast inoculation amount is 15MM / mL.

[0052] Among them, the yeast is lager yeast.

[0053] As a preferred embodiment, step S2 includes the following:

[0054] S21. Filter, add yeast for fermentation. The yeast addition amount is 1% - 1.5% of the volume of the wort, the fermentation temperature is 11 - 15 °C, and the fermentation time is 4 - 5 days;

[0055] S22. Cool down the temperature to 10 - 12 °C and recover the yeast;

[0056] S23. Cool down the temperature to 8 - 10 °C and continue fermentation until the content of free diacetyl in the fermentation broth is ≤ 15 ppb and the content of acetaldehyde is ≤ 10 ppb, then obtain the beer.

[0057] In the fourth aspect of the present invention, a beer is provided, which is obtained by the above production method.

[0058] Compared with the prior art, the present invention has the following beneficial effects:

[0059] (1) The method for enlarged cultivation of lactic acid bacteria in the present invention uses wort in beer production as the culture medium, produces a fermentation broth containing lactic acid through enlarged cultivation, and uses this fermentation broth for wort fermentation to obtain acid wort with a pH of 3 - 4. Using the acid wort to adjust the pH value in beer brewing will not bring astringency to the beer.

[0060] (2) By using the production method of acid wort in the present invention, acid wort with a light yellow appearance, clean lactic acid taste, no sour smell, no astringency, and no bitterness can be obtained.

[0061] (3) By using the production method of beer in the present invention, the obtained beer has a green apple taste, no obvious sourness, slight ester aroma, clean bitterness, no aftertaste bitterness, clean body, and quick disappearance.

[0062] (4) By using the production method of beer in the present invention and adjusting the pH value through acid wort, the problems of premature aging of yeast caused by using food-grade phosphoric acid to adjust the pH value and the increased cost caused by domestic lactic acid are overcome.

[0063] (5) By using the production method of beer in the present invention, the fermentation speed and fermentation productivity are significantly improved, and the power consumption of each fermentation tank can be saved by up to 200°.

[0064] The concept, specific structure and technical effects of the present invention will be further described below in conjunction with the drawings to fully understand the purpose, features and effects of the present invention. Brief Description of the Drawings

[0065] Figure 1 is the process flow chart of the method for enlarged cultivation of lactic acid bacteria in the present invention;

[0066] Figure 2 is the equipment diagram of the method for enlarged cultivation of lactic acid bacteria in the present invention. Detailed Embodiments

[0067] In order to make the technical means, creative features, achieved purposes and effects of the invention easy to understand, the present invention will be further described below in conjunction with specific drawings. However, the present invention is not limited to the following implemented cases.

[0068] It should be noted that the structures, proportions, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those familiar with this technology to understand and read, and are not used to limit the conditions for the implementation of the present invention. Therefore, they do not have substantial technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope covered by the technical content disclosed in the present invention.

[0069] Beer brewing involves eight major steps. The first step is raw material preparation, where malt is crushed and the crushed malt is mixed with hot water. The second step is the saccharification process, where the mixture is heated to an appropriate temperature to promote the activity of enzymes, enabling the enzymes to break down starch into sugar, forming sweet wort. The third step is to filter the saccharified liquid. The saccharified liquid is filtered through a filter screen to remove dregs and solid particles, obtaining a clear liquid. The fourth step is the boiling and adding hops step. The saccharified liquid is boiled, and during the boiling process, hops are added. The fifth step is the cooling and fermentation step. The boiled liquid is quickly cooled to the fermentation temperature, yeast is added to the boiled liquid, and it is transferred to a fermentation tank for fermentation. The sixth step is the aging step. The beer is stored in a low-temperature environment to improve its taste and stability. The seventh step is filtration and carbonation. Residual solid particles and suspended matter are removed by filtration, and then carbon dioxide is injected to make the beer have an appropriate carbon dioxide content. The eighth step is filling and packaging.

[0070] During the beer production process, since the brewing water of beer contains more bicarbonate ions, carbonate ions, and hydroxide ions, and when the quality of the malt used is poor and the content of acidic salts is too low, it is difficult to make the malt mash reach the optimal pH value, and additional acid needs to be added for adjustment. Commonly, food-grade phosphoric acid or lactic acid is added. Excessive phosphorus will cause premature aging of yeast, while excessive lactic acid will bring astringency.

[0071] In order to improve the quality of beer and at the same time enhance the fermentation efficiency, the inventors of the present application tried to use the wort inherent in beer production as a culture medium to culture lactic acid bacteria, and use the lactic acid produced by lactic acid bacteria to be recycled in beer production to overcome the astringency brought by traditional lactic acid.

[0072] The present application provides a method for the enlarged cultivation of lactic acid bacteria, including the following steps:

[0073] S1. Take the saccharified wort and add it to a culture bottle, cool it to 40 - 48 °C, inoculate lactic acid bacteria into the culture bottle, the volume ratio of wort to lactic acid bacteria is (97 - 98):(2 - 3), and the addition amount of lactic acid bacteria is 2×10 7CFU / mL, the primary culture medium is cultured until the pH < 4.0, the wort has a sugar content of 12 - 18 °P, and the volume percentage of the saccharified wort in the culture flask is 97% - 98%;

[0074] S2. First stage of scale-up culture:

[0075] Take the saccharified wort and add it to a Carlsberg flask, cool it to 40 - 48 °C, add the primary culture medium to obtain a secondary culture medium with pH < 4.0. The volume percentage of the saccharified wort in the Carlsberg flask is 95% - 99%, and the volume ratio of the Carlsberg flask to the culture flask is (20 - 250):1;

[0076] S3. Second stage of scale-up culture:

[0077] Take the saccharified wort, dilute it with water and add it to a first-stage culture tank, cool it to 40 - 48 °C, add the secondary culture medium to obtain a tertiary culture medium with pH < 4.0. The volume percentage of the saccharified wort in the first-stage culture tank is 50% - 55%, the volume percentage of the added water in the first-stage culture tank is 10% - 15%, and the volume ratio of the first-stage culture tank to the Carlsberg flask is (8 - 50):1;

[0078] S4. Third stage of scale-up culture:

[0079] Take the saccharified wort, dilute it with water and add it to a second-stage culture tank, cool it to 40 - 48 °C, add the tertiary culture medium to obtain a quaternary culture medium with pH < 4.0. The volume percentage of the saccharified wort in the second-stage culture tank is 50% - 55%, the volume percentage of the added water in the second-stage culture tank is 10% - 15%, and the volume ratio of the second-stage culture tank to the first-stage culture tank is (2 - 10):1;

[0080] S5. Fourth stage of scale-up culture:

[0081] Take the saccharified wort, dilute it with water and add it to a third-stage culture tank, cool it to 40 - 48 °C, add the quaternary culture medium to obtain a fermentation broth with pH < 4.0. The volume percentage of the saccharified wort in the third-stage culture tank is 50% - 55%, the volume percentage of the added water in the third-stage culture tank is 10% - 15%, and the volume ratio of the third-stage culture tank to the second-stage culture tank is (2.5 - 10):1.

[0082] The lactic acid bacteria here are purchased from Jinan Jinyuyuan Biotechnology Co., Ltd. After the lactic acid bacteria (including a small amount of culture medium) are taken out from the frozen environment, an activation step is required to meet the requirements of subsequent scale-up culture. Different activation temperatures can affect the duration of the entire activation process. In this application, the lactic acid bacteria taken out from the frozen environment are cultured at different temperatures of 40 - 48 °C, and the obtained results are shown in Table 1.

[0083] Table 1

[0084]

[0085] Since lactic acid bacteria produce lactic acid, the pH of the system decreases. When the pH of the system where lactic acid bacteria are located is around 4.0, it indicates that the lactic acid bacteria are in an activated state. Therefore, pH = 4 or below is used as the sign for the end of the activation stage of lactic acid bacteria. As shown in Table 1, when the environmental temperature is controlled at 44 °C, the lactic acid bacteria can be activated within a relatively short time (24 h). When the temperature is lower or higher than this value, the activation time is relatively long.

[0086] During the process of enlarged cultivation of lactic acid bacteria, the level of the cultivation temperature will affect the activity of lactic acid bacteria. In this application, lactic acid bacteria are added to the saccharified wort, and the time required for the pH of the system to reach below 4 at different temperatures is investigated. The results are shown in Table 2.

[0087] Table 2

[0088]

[0089]

[0090] As shown in Table 2, the optimal temperature for lactic acid bacteria during the cultivation stage is 46 °C. At this time, it takes 24 h for the pH to reach below 4. When the cultivation temperature is 44 °C, it takes 36 h for the system pH to reach below 4. It can be seen that when using saccharified wort as the culture medium, a small change in the cultivation temperature will bring a huge difference in the cultivation results.

[0091] In addition, the selection of the culture medium is also crucial. The culture medium is the basis for the growth of lactic acid bacteria. In this application, two kinds of worts are used for cultivation respectively. One is the first-run wort that has not been boiled and has no hops added; the other is the cold wort that has been boiled and has hops added. The cultivation results are shown in Table 3.

[0092] Table 3

[0093]

[0094] As shown in Table 3, hops are added to the cold wort. Since hops may have an inhibitory effect on lactic acid bacteria, it takes a longer time for the pH in the system to reach below 4. Therefore, this application is suitable for using the first-run wort.

[0095] The enlarged cultivation of lactic acid bacteria in this application includes five steps. At the end of each step, the pH range of the system determines the activity of lactic acid bacteria in the next step and affects the enlarged cultivation of lactic acid bacteria in the next step. In this application, the influence of the pH value at the end of each cultivation stage on the next step or the next cultivation stage is investigated. The results are shown in Table 4.

[0096] Table 4

[0097]

[0098]

[0099] As shown in Table 4, when the pH value of the system before transferring to the next-level culture is controlled at 3.8, 4, and 4.2, wort is added to the obtained system for expanded culture. After 28 h, the pH value of the new system returns to below 4 again; however, when the pH value of the upper-level culture system drops below 3.6, adding wort for expanded culture, when the pH value of the next-level culture system returns to below 4 again, the time required is more than 32 h. Therefore, using wort as the culture medium, controlling the pH value of the system is crucial.

[0100] Among them, the above-mentioned culture bottles, carboys, primary culture tanks, secondary culture tanks, and tertiary culture tanks also involve a sterilization step before use.

[0101] Among them, the saccharified wort is the wort obtained after the saccharification step of the raw materials for beer production.

[0102] The preparation method of the above-mentioned saccharified wort is as follows:

[0103] S1. Take malt, rice, and water, and the weight ratio of malt, rice, and water is 22:12:66;

[0104] S2. Crush the malt and rice;

[0105] S3. Add the crushed rice powder and water to the mashing pot, boil for 10 minutes to obtain mash;

[0106] S4. Add the crushed malt powder and water to the saccharification pot, add calcium sulfate, and rest at 44 °C for 10 minutes;

[0107] S5. Transfer the mash in the mashing pot to the saccharification pot, raise the temperature to 66 °C, hold for 20 min, then raise the temperature to 74 °C to obtain wort mash, and filter the wort mash to obtain wort with a sugar degree of 12-18 °P.

[0108] This application also provides a production method of sour wort, including the following steps:

[0109] S1. Take the saccharified wort (with a sugar degree of 12-18 °P) and the fermentation broth obtained by the above-mentioned lactic acid bacteria expanded culture method, add them to the culture tank, and the volume ratio of wort to fermentation broth is (3.5-4.5):(0.5-1.5), preferably 4:1;

[0110] S2. Ferment at 40-48 °C to obtain sour wort with a pH of 3-4.

[0111] The present application also provides a method for producing beer, comprising the following steps:

[0112] S1. Add the saccharified wort into a boiling pot, add hops during the boiling process, and add the above-mentioned sour wort before the end of boiling, wherein the addition amount of the sour wort accounts for 1.0% - 1.5% of the total volume of the wort, the addition amount of hops accounts for 0.04% - 0.05% of the total volume of the wort, and the pH of the system is 5.2 - 5.3;

[0113] S2. Filter and add yeast for fermentation. The inoculation amount of yeast is 15MM / mL (i.e., there are 15 million yeasts per milliliter of wort), the fermentation temperature is 11 - 15 °C, and the fermentation time is 4 - 5 days; cool down to 10 - 12 °C to recover yeast; cool down to 8 - 10 °C and continue fermentation until the content of free diacetyl in the fermented liquid is ≤15 ppb and the content of acetaldehyde is ≤10 ppb to obtain beer.

[0114] Example 1

[0115] A method for enlarged cultivation of lactic acid bacteria, as Figure 1 、 2 , comprising the following steps:

[0116] S1. Sterilize a 250 mL culture bottle using an autoclave, take 100 mL of sterilized saccharified wort after sterilization (at this time, the wort is the first-run wort, not the weak wort generated during the cleaning process, and the sugar degree of the wort is 14 °P) and add it into the sterilized culture bottle, cool it to 46 °C, then inoculate 1 mL of lactic acid bacteria (purchased from Jinan Jinyuyuan Biotechnology Co., Ltd.) into the culture bottle, and the dosage of lactic acid bacteria corresponding to each mL of wort is 2×10 7 CFU, and culture at 46 °C for 1 - 2 days to obtain a primary culture solution with pH < 4.0.

[0117] Step S1 belongs to the laboratory stage, and the whole operation is carried out in a laboratory with a cleanliness level of Class C or above. The operation tools and culture media used are sterilized by an autoclave, and the sterilization conditions are 121.3 °C for 30 min, and the operation is carried out in a laminar flow hood.

[0118] S2. Take the saccharified wort (the addition amount is 9.8 L) and add it into a 10 L Carlsberg tank, sterilize the Carlsberg tank using an autoclave, cool it to 46 °C, add the primary culture solution obtained in Step S1 (add all the primary culture solution), and culture at 46 °C for 1 - 2 days to obtain a secondary culture solution with pH < 4.0.

[0119] S3. Clean and steam sterilize the 3HL primary culture tank. Take the saccharified wort (take 1.5HL of wort and dilute it with 31L of water) and add it to the primary culture tank. Cool it to 46°C, add the secondary culture solution obtained in step S2 (add all of the secondary culture solution), and culture it at 46°C for 1 - 2 days to obtain a tertiary culture solution with pH < 4.0.

[0120] S4. Clean and steam sterilize the 15HL secondary culture tank. Take the saccharified wort (7.7HL) and add it to the secondary culture tank and dilute it with water (the amount of added water is 2.3HL). Cool it to 46°C, add the tertiary culture solution obtained in step S3 (add all of the tertiary culture solution), and culture it at 46°C for 1 - 2 days to obtain a quaternary culture solution with pH < 4.0.

[0121] S5. Clean and steam sterilize the 100HL tertiary culture tank. Take the saccharified wort (the amount used is 55HL) and add it to the tertiary culture tank and dilute it with water (the amount of added water is 13HL). Cool it to 40 - 48°C, add the quaternary culture solution obtained in step S4 (add all of the quaternary culture solution), and culture it at 46°C for 1 - 2 days to obtain a fermentation broth with pH < 4.0.

[0122] By establishing an aseptic operation method, the purity and singularity of the strain can be ensured, and the taste of lactic acid can be ensured to be unified; the four - stage expansion culture process ensures the growth of lactic acid bacteria in a stable environment and reduces the generation of by - products.

[0123] Among them, the saccharified wort above is prepared by the following method:

[0124] S01. Take 12000 kg of Planet malt, 6500 kg of rice, 30 kg of Hercules hops, and 35000 kg of water.

[0125] S02. Crush the malt and rice. After the malt is crushed by a hammer mill, it enters the malt powder temporary storage bin for standby.

[0126] S03. Add the crushed rice powder and water to the mash kettle, boil for 10 minutes to obtain a mash.

[0127] S04. Mix the crushed malt powder and water through a malt slurry mixer and add them to the mash kettle, add calcium sulfate (accounting for 0.06% of the mash), and rest at 44°C for 10 minutes.

[0128] S05. Transfer the mash in the mash kettle to the mash kettle, raise the temperature to 66°C, hold for 20 min, then raise the temperature to 74°C to obtain a wort mash. Filter the wort mash through a filter press or a filter trough to obtain 18°P wort.

[0129] Example 2

[0130] A method for producing sour wort, comprising the following steps:

[0131] S1. Take the saccharified wort prepared in Example 1 and the fermentation broth obtained by the above-mentioned lactic acid bacteria enlarged culture method, add them into a culture tank, and the volume ratio of the wort to the fermentation broth is 4:1;

[0132] S2. Ferment at 40-48 °C to obtain sour wort with a pH of 3-4.

[0133] Example 3

[0134] A method for producing beer, comprising the following steps:

[0135] S1. Add the saccharified wort prepared in Example 1 into a boiling pot, and boil at 100 °C for 60-70 min. 5 min before the start of boiling, add the sour wort prepared in Example 2. During the boiling process, when the wort temperature reaches 98.1 °C, add hops (0.04% of the wort volume), and add the sour wort at a ratio of 1.0% of the wort volume. Adjust the pH of the wort in the boiling pot to 5.25 after adjustment.

[0136] S2. Transfer the acidified wort to a whirlpool settling tank and perform a 10-min whirlpool settling rest; after the rest, cool the wort, control the temperature at 9-11 °C, introduce sterile air, control the oxygen content in the wort at 9-12 ppb, and add yeast (here the yeast is lager yeast), and the addition amount of yeast per milliliter of wort is 15MM.

[0137] S3. After adding yeast, perform fermentation, control the fermentation temperature at 11-15 °C, ferment for 4-5 days, cool down to 10-12 °C, and recover the yeast.

[0138] S4. After yeast recovery, lower the temperature to 8-10 °C for fermentation. When the contents of free diacetyl and acetaldehyde in the fermentation broth are reduced to 15 ppb and 10 ppb respectively, cool down to 0 °C for storage. Obtain clear beer through centrifugal filtration, and finally perform bottling to obtain beer.

[0139] Example 4

[0140] Different from Example 3, the pH of the wort in the boiling pot obtained after adjustment with sour wort in step S1 is 5.0.

[0141] Example 5

[0142] Referring to the method of Example 2, control the fermentation temperature and the sugar content of the wort, so that the fermentation temperature varies within the range of 40-48 °C, and the sugar content of the saccharified wort varies within the range of 12-18 °P, and compare the quality of the produced sour wort.

[0143] The quality assessment of sour wort is mainly measured by physical and chemical indicators and sensory tasting. The physical and chemical indicators of sour wort obtained under different conditions are pH < 4.0, all of which are qualified. For sour wort with better quality, appearance: light yellow; smell: clean lactic acid smell, without sour and stinky smell; taste: gentle sour taste, without astringency and bitterness. The sensory tasting is scored by the members of the key tasting panel (a total of 40 people), and the average value is taken finally. The score is from 1 to 10 points, with 1 point being the worst and 10 points being the best. The evaluation results are shown in Table 5.

[0144] Table 5

[0145]

[0146] As can be seen from Table 1, when the fermentation temperature of sour wort is controlled at 46 °C and the wort extract is controlled at 14 °P, the best sensory evaluation results of sour wort are obtained. Therefore, the fermentation temperature of sour wort can be controlled at 46 °C, and the wort extract after saccharification can be controlled at 14 °P.

[0147] The sour wort obtained at a fermentation temperature of 46 °C and a wort extract of 14 °P is stored in an environment of 10 °C for 1 - 7 days, and the pH change and sensory evaluation scores at different days are compared. The results are shown in Table 6.

[0148] Table 6

[0149]

[0150] As can be seen from Table 6, during the storage process, the pH change of sour wort is not significant, but after the 6th day, the sensory evaluation score will decrease significantly. Therefore, it is more appropriate to keep the best use time of sour wort within one week.

[0151] Comparative Example 1

[0152] A method for producing beer includes the following steps:

[0153] S1. Add the saccharified wort into a boiling pot and boil it at 100 °C for 60 - 70 min. During the boiling process, when the wort temperature reaches 98.1 °C, add hops (0.04% of the volume of the saccharified wort). At this time, the pH of the wort in the boiling pot is 5.5.

[0154] S2. Transfer the wort to a whirlpool clarifier and carry out a 10 - minute whirlpool sedimentation rest; after the rest, the wort is cooled, and the temperature is controlled at 9 - 11 °C. Sterile air is introduced, and the oxygen content in the wort is controlled at 9 - 12 ppb. Add yeast (here the yeast is lager yeast), and the yeast addition amount is 1% of the volume of the saccharified wort;

[0155] S3. After adding yeast, conduct fermentation. Control the fermentation temperature at 11 - 15 °C for 4 - 5 days, then cool down to 10 - 12 °C and recover the yeast.

[0156] S4. After yeast recovery, lower the temperature to 8 - 10 °C for fermentation. When the contents of free diacetyl and acetaldehyde in the fermentation broth are reduced to 15 ppb and 10 ppb respectively, cool down to 0 °C for storage. Obtain clear beer through centrifugal filtration, and finally conduct bottling to obtain a kind of beer.

[0157] The difference between Comparative Example 1 and Example 3 and Example 4 is that no acid wort was added in Comparative Example 1, and the index comparison of the obtained beer is shown in Table 7.

[0158] Table 7

[0159]

[0160] As shown in Table 7, compared with Example 3, in Example 4, because the pH of the fermented wort is lower than 5.2, the finally obtained beer has a slight astringent taste. In Comparative Example 1, because no acid wort was added during the beer production process, it is difficult for the malt mash to reach the optimal pH value, and the prepared beer has a bitter and lingering taste in the mouth. Therefore, controlling the pH of the fermented wort is crucial.

[0161] The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations according to the concept of the present invention without creative work. Therefore, all technical solutions that can be obtained by those skilled in the art in the technical field based on the concept of the present invention through logical analysis, reasoning or limited experiments on the basis of the prior art should be within the protection scope determined by the claims.

Claims

1. A method for the enlarged cultivation of lactic acid bacteria, characterized in that, It includes the following steps: S1. Take the saccharified wort and add it to a culture flask, cool it to 40 - 48 °C, inoculate lactic acid bacteria into the culture flask to obtain a primary culture solution with pH < 4.0, and the sugar content of the wort is 12 - 18 °P; S2. First stage of enlarged culture: Take the saccharified wort and add it to a Carlsberg flask, cool it to 40 - 48 °C, add the primary culture solution to obtain a secondary culture solution with pH < 4.0, and the volume ratio of the Carlsberg flask to the culture flask is (20 - 250):1; S3. Second stage of enlarged culture: Take the saccharified wort, dilute it with water and add it to a first - stage culture tank, cool it to 40 - 48 °C, add the secondary culture solution to obtain a tertiary culture solution with pH < 4.0, and the volume ratio of the first - stage culture tank to the Carlsberg flask is (8 - 50):1; S4. Third stage of enlarged culture: Take the saccharified wort, dilute it with water and add it to a second - stage culture tank, cool it to 40 - 48 °C, add the tertiary culture solution to obtain a quaternary culture solution with pH < 4.0, and the volume ratio of the second - stage culture tank to the first - stage culture tank is (2 - 10):1; S5. Fourth stage of enlarged culture: Take the saccharified wort, dilute it with water and add it to a third - stage culture tank, cool it to 40 - 48 °C, add the quaternary culture solution to obtain a fermentation broth with pH < 4.0, and the volume ratio of the third - stage culture tank to the second - stage culture tank is (2.5 - 10):

1.

2. The method for enlarged cultivation of lactic acid bacteria according to claim 1, wherein It also includes the step of sterilizing the culture flask, Carlsberg flask, first - stage culture tank, second - stage culture tank, and third - stage culture tank.

3. The method for the enlarged cultivation of lactic acid bacteria according to claim 1, characterized in that, The saccharified wort is the wort obtained after the saccharification step of the raw materials for beer production.

4. The method for enlarged cultivation of lactic acid bacteria according to claim 1, wherein The culture temperature in steps S1 - S5 is 46 °C.

5. The method for large-scale cultivation of lactic acid bacteria according to claim 1, characterized in that, The pH after culturing in each step is controlled at 3.

6.

6. A method for producing acid wort, characterized in that, It includes the following steps: S1. Take the saccharified wort and the fermentation broth obtained by the lactic acid bacteria enlarged culture method according to any one of claims 1 - 5, add them to a culture tank, and the volume ratio of the wort to the fermentation broth is (3.5 - 4.5):(0.5 - 1.5); S2. Ferment at 40 - 48 °C to obtain acid wort with pH 3 - 4.

7. A method for producing beer, characterized in that, It includes the following steps: S1. Add the saccharified wort to a boiling pot, add hops during the boiling process, and add the acid wort according to any one of claims 5 - 6 before the end of boiling. The addition amount of the acid wort accounts for 1.0% - 1.5% of the total volume of the wort, the addition amount of hops accounts for 0.04% - 0.05% of the total volume of the wort, and the pH of the system is 5.2 - 5.3; S2. Filter and ferment to obtain beer.

8. The production method of beer according to claim 7, characterized in that, In step S2, yeast is added, and the yeast inoculation amount is 15MM / ml.

9. The production method of beer according to claim 7, characterized in that, Step S2 includes the following: S21. Filter, add yeast for fermentation, the yeast addition amount is 1% - 1.5% of the volume of the wort, the fermentation temperature is 11 - 15 °C, and the fermentation time is 4 - 5 days; S22. Cool down to 10 - 12 °C to recover yeast; S23. Cool down to 8 - 10 °C and continue fermentation until the content of free diacetyl in the fermentation broth ≤ 15 ppb and the content of acetaldehyde ≤ 10 ppb to obtain beer.

10. A beer, characterized in that, It is obtained by using the production method according to any one of claims 7 - 9.

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