A production process for preparing aged vinegar by using highland barley wine lees

Abstract

The application relates to the field of food brewing, and discloses a brewing composition and process for preparing aged vinegar from highland barley wine lees. The raw materials of the composition include highland barley wine lees, Huangyuan aged vinegar brewing Daqu, bran, rice husk and salt. The production process comprises the following steps: firstly, mixing the wine lees, the Daqu and a first part of the bran, and controlling the conditions to carry out solid anaerobic alcohol fermentation; then, adding the remaining second part of the bran and the rice husk to carry out solid acetic acid fermentation; adding salt at the end of fermentation to seal and mature; and finally, obtaining the finished product through vinegar pouring and sterilization. Through the step-by-step addition of bran and the anaerobic-aerobic two-stage fermentation strategy, the carbon and nitrogen sources required for microbial metabolism are effectively supplemented, the problem of low acid production when directly brewing vinegar from highland barley wine lees is solved, and the utilization rate of raw materials, the physical and chemical indexes and the sensory quality of the finished product are significantly improved.

Description

Technical Field

[0001] This invention relates to the field of food brewing technology, specifically a production process for preparing aged vinegar using barley wine lees. Background Technology

[0002] Barley lees are a solid byproduct of barley wine brewing and distillation. With the expansion of barley wine production, the amount of lees generated is increasing daily. Currently, barley lees are mostly used as inexpensive animal feed or discarded directly, resulting in a waste of biomass resources and placing environmental pressure on the environment. Utilizing lees to brew vinegar is an effective way to achieve high-value utilization of this resource, but technical bottlenecks still exist in actual production.

[0003] After fermentation and distillation, the residual fermentable sugars, starches, and available nitrogen sources in barley lees are significantly reduced. In traditional vinegar-making processes, this characteristic of the raw material is often not addressed with targeted nutritional supplementation and process control. This results in insufficient carbon sources in the fermentation system for yeast to convert into ethanol, a necessary precursor for subsequent acetic acid fermentation. Due to insufficient substrate concentration, the subsequent acetic acid fermentation process often has low conversion efficiency, making it difficult to increase the total acid content of the final product and meet the physicochemical requirements of high-quality aged vinegar.

[0004] Furthermore, existing vinegar-making processes using distiller's grains often employ a relatively crude one-step mixed fermentation method or simple solid-state fermentation, failing to precisely control the flow of oxygen and nutrients according to the metabolic needs of different microbial strains at different stages. This technological deficiency not only affects the utilization rate of raw materials but also leads to a lack of synthesis and accumulation of flavor compounds such as esters during fermentation, resulting in a finished product with a pungent vinegar taste, weak aroma, and rough texture, making it difficult to meet consumers' demand for high-quality brewed vinegar. Summary of the Invention

[0005] The technical problem solved by this invention is that in the existing process of producing vinegar from barley wine lees, the low residual fermentable sugar content in the lees leads to insufficient accumulation of ethanol precursors due to direct fermentation, resulting in low acidity, weak flavor, and low raw material utilization in the finished vinegar.

[0006] To address the above problems, the present invention provides the following technical solution: In a first aspect, the present invention provides a brewing composition for preparing aged vinegar using barley wine lees, employing the following technical solution: A brewing composition for preparing aged vinegar using barley wine lees, the composition being made from the following raw materials in parts by weight: 1000 parts barley wine lees; 18-20 parts Huangyuan aged vinegar brewing starter; 460-500 parts wheat bran; 380-420 parts rice husks; and 14-16 parts salt.

[0007] By adopting the above technical solution, this invention achieves the supplementation of nutrients in highland barley lees and the optimization of the fermentation substrate through raw material ratio: Barley wine lees, as a solid byproduct of distillation, have low starch and available nitrogen content. This invention introduces wheat bran into the formula, providing auxiliary carbon and nitrogen sources. The starch in the bran is hydrolyzed into fermentable sugars by the Daqu enzyme system in the early stages of fermentation, providing a substrate for yeast to produce ethanol; the protein in the bran is degraded into amino acids, providing nitrogen nutrition for the growth and metabolism of acetic acid bacteria, and participating in flavor formation as a precursor to the Maillard reaction.

[0008] The brewing starter culture for Huangyuan aged vinegar provides microbial flora and saccharifying and liquefying enzyme systems, which help degrade the residual fiber components in the lees.

[0009] Rice husks, used as a filler, create a suitable pore structure, increase the gas-liquid contact area, ensure the mass transfer efficiency of oxygen during the aerobic fermentation stage, and prevent the inhibition of acetic acid bacteria activity due to local hypoxia.

[0010] Preferably, the raw materials are in the following weight proportions: 1000 parts of highland barley wine lees; 19 parts of Huangyuan aged vinegar brewing starter; 480 parts of wheat bran; 400 parts of rice husk; and 15 parts of salt.

[0011] By adopting the above technical solution, this formula increases the proportion of lees added while ensuring fermentation efficiency, thus balancing production costs and product quality.

[0012] Preferably, the barley wine lees are solid byproducts after the solid-state fermentation and distillation of barley wine, and their water content is 60%-65%.

[0013] By adopting the above technical solution, limiting the moisture content of the lees helps maintain the moisture balance of the initial fermentation system and reduces the need for additional water addition or drying pretreatment steps.

[0014] Preferably, the bran is wheat bran; the rice husk is dried rice husk; and the moisture content of the Huangyuan aged vinegar brewing starter is less than 13%.

[0015] Secondly, the present invention provides a production process for preparing aged vinegar using barley wine lees, employing the following technical solution: A production process for preparing aged vinegar using barley wine lees includes the following steps: S1. Solid-state alcoholic fermentation of lees: Take the barley wine lees, cool them down, add the Huangyuan aged vinegar brewing koji and the bran from the first part, mix them evenly and put them into a fermentation container. Control the temperature of the product and the ambient temperature to carry out sealed anaerobic fermentation to obtain alcoholic fermentation mash. S2. Solid-state acetic acid fermentation and post-fermentation: Add the remaining second part of the bran and rice husk to the alcoholic fermentation mash obtained in step S1, mix evenly, and then carry out solid-state acetic acid fermentation. During the fermentation process, the mash is turned over periodically and the temperature is controlled until the acidity of the vinegar no longer increases. Then add the salt, turn the mash over evenly, seal and store for post-fermentation to obtain acetic acid fermentation mash. S3, Vinegar Leaching and Sterilization: The vinegar mash after the S2 step is fermented with vinegar, the vinegar liquid is collected, and sterilized to obtain the finished aged vinegar.

[0016] By adopting the above technical solution, this invention solves the problem of low acid production from distiller's grains by combining stepwise feeding with a two-stage anaerobic-aerobic fermentation process. Its mechanism of action is as follows: In step S1, the addition of the first portion of wheat bran replenishes the starchy raw material lacking in the distiller's grains. The sealed anaerobic environment inhibits the growth of aerobic bacteria, forcing the yeast to undergo anaerobic respiration. The molds in the koji (fermentation starter) degrade the wheat bran starch into glucose, which the yeast then uses to produce ethanol via glycolysis. This step provides the acetic acid precursor (ethanol) for subsequent acetic acid fermentation, avoiding the low acid production rate caused by insufficient substrate in direct mixed fermentation. Simultaneously, the anaerobic environment is conducive to the synthesis of esters and higher alcohols, increasing the ester aroma of the finished vinegar.

[0017] In the first half of step S2, after ethanol accumulation, the remaining second portion of wheat bran is added to replenish nitrogen and growth factors, maintaining the physiological activity of acetic acid bacteria in the later stages of fermentation. Simultaneously, the addition of rice husks increases the looseness and porosity of the material, transforming the fermentation environment into an aerobic state. Under sufficient oxygen supply and suitable temperature, acetic acid bacteria adhere to the surface of the solid substrate and utilize the ethanol accumulated in stage S1 to oxidize it into acetic acid through an enzymatic reaction.

[0018] In the latter half of step S2, during the post-ripening process, the addition of salt adjusts the flavor and inhibits unwanted microorganisms. The newly generated acetic acid undergoes an esterification reaction with the alcohols remaining in the system, reducing the harshness of the new vinegar and creating a mellow taste.

[0019] Preferably, in step S1, the bran is added in stages as follows: the amount of bran added in the first part is 170-190 parts by weight; in step S2, the amount of bran added in the remaining second part is 290-310 parts by weight.

[0020] By adopting the above technical solution, the bran ratio of approximately 1:1.6 is controlled to meet the metabolic needs of microorganisms. The first part of the bran supports the yeast in producing an appropriate concentration of alcohol, while the second part of the bran supports the aerobic metabolic consumption of acetic acid bacteria and serves as the source of solids in the final product.

[0021] Preferably, step S1 is implemented as follows: cool the barley wine lees to 36-40℃, add Huangyuan aged vinegar brewing starter and the bran from the first part and mix evenly; when the material temperature naturally rises to 29-31℃, compact the material and seal it tightly with plastic sheeting; control the fermentation chamber temperature at 22-28℃, the fermentation time is 5-7 days, and the alcohol concentration is controlled at 5%vol-7%vol at the end of fermentation.

[0022] By adopting the above technical solutions, the compaction and sealing operations create anaerobic conditions, reducing the oxidation or volatilization of ethanol; the alcohol concentration at the end of fermentation is controlled at 5-7% vol, which is within the suitable substrate concentration range for acetic acid bacteria conversion, avoiding excessively high concentrations that inhibit the activity of acetic acid bacteria or excessively low concentrations that lead to insufficient acid production.

[0023] Preferably, in step S2, the solid-state acetic acid fermentation is specifically implemented as follows: the alcohol concentration of the fermented mash after step S1 is detected and adjusted to 5.8%vol-6.2%vol; the remaining bran and rice husks from the second part are added to make the material loose and solid; the mash is turned over once a day during fermentation, and the temperature is controlled at 38-42℃; when the acidity of the vinegar juice is continuously stable and no longer increases, it is determined to be the end of fermentation.

[0024] By adopting the above technical solution, the pouring operation plays a role in heat dissipation, ventilation and mixing of inoculum; controlling the product temperature at 38-42℃ is conducive to maintaining the activity of the acid-producing enzyme system of Acetic Acid Bacillus and increasing the conversion rate of ethanol to acetic acid.

[0025] Preferably, in step S2, the addition of salt and post-fermentation are performed as follows: after determining the fermentation endpoint, add salt, continue to pour the mash once a day for a total of 2-3 times, then compact and flatten the vinegar mash, cover the surface to isolate it from air, and perform post-fermentation.

[0026] By adopting the above technical solution, the fermentation process is completed by compacting and flattening the soil to isolate it from the air, preventing the acetic acid bacteria from continuing to oxidize acetic acid into carbon dioxide and water, thereby protecting the acetic acid that has already been generated from being consumed.

[0027] Preferably, in step S3, the vinegar leaching is performed using a solid vinegar leaching method, which involves spraying and soaking raw vinegar juice with drinking water or secondary vinegar leaching; the sterilization is performed by heat sterilization.

[0028] This invention provides a production process for preparing aged vinegar using barley wine lees. It has the following beneficial effects: 1. This invention effectively solves the problem of insufficient carbon and nitrogen sources when using highland barley lees as a raw material for vinegar brewing through a step-by-step bran addition strategy. Adding a portion of bran in the first stage provides sufficient fermentable sugars for yeast to accumulate ethanol precursors; supplementing with the remaining bran in the second stage provides the necessary nitrogen source and growth factors for acetic acid bacteria, maintaining their metabolic activity in the later stages of fermentation. This segmented nutrient supply model significantly improves the bioconversion rate of the raw materials, resulting in a marked increase in the total acid content of the finished vinegar.

[0029] 2. This invention constructs a strict anaerobic-to-aerobic fermentation system, optimizing the metabolic environment of microorganisms at different stages. In the early stage, compaction and sealing create an anaerobic environment, inhibiting ineffective oxidative consumption of the substrate and ensuring efficient ethanol accumulation. In the later stage, the addition of rice husks and turning the mash increases the porosity of the material, enhancing oxygen mass transfer and promoting the rapid conversion of ethanol to acetic acid. This process flow is clearly defined, effectively shortening the fermentation cycle and improving production efficiency.

[0030] 3. This invention significantly improves the sensory quality of highland barley lees vinegar. The anaerobic alcoholic fermentation stage not only accumulates ethanol but also metabolizes and generates flavor precursors such as esters and higher alcohols. Combined with the salting and ripening process, it promotes the esterification reaction between acetic acid and alcohols, increasing the ester aroma of the finished vinegar, reducing the harshness of new vinegar, and making its taste more mellow and rich. Attached Figure Description

[0031] Figure 1 This is a flowchart of the present invention. Detailed Implementation

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Example 1: Please see the appendix Figure 1 This invention provides a production process for preparing aged vinegar using barley wine lees, comprising: (1) Fermentation of lees into solid state: Take 1000 parts by weight of barley wine lees after distillation, let it cool naturally, and when the temperature drops to 38℃, add 180 parts by weight of wheat bran and 19 parts by weight of Huangyuan aged vinegar brewing koji, stir evenly, and put it into a fermentation tank; when the temperature of the material naturally rises to 30℃, tamp the mash down, cover it tightly with plastic sheeting, control the temperature in the fermentation room at 25℃, and carry out anaerobic fermentation for 6 days; after the fermentation is completed, the alcohol concentration is measured to be 6.5% vol; (2) Solid-state acetic acid fermentation: Take out the fermented material from step (1), test and adjust the alcohol concentration to 6.0% vol; add 300 parts by weight of wheat bran and 400 parts by weight of rice husk, mix evenly; enter the acetic acid fermentation stage, pour the mash once a day, control the temperature at 40℃ through heat dissipation and heat preservation measures, test the acidity regularly, and when the acidity of the vinegar no longer increases, it is the end of fermentation; at this time, add 15 parts by weight of salt, continue to pour the mash once a day, pour the mash 3 times in total, and then tread the mash for post-ripening; (3) Vinegar leaching and sterilization: The fermented vinegar mash is placed in a vinegar leaching tank for vinegar leaching and the vinegar liquid is collected; the vinegar liquid is heated and sterilized, and then cooled to obtain the finished product.

[0034] Example 2: This embodiment provides a process for producing aged vinegar using barley wine lees, including the following steps: (1) Fermentation of lees into solid state: Take 1000 parts by weight of barley wine lees after distillation, let it cool naturally, and when the temperature drops to 36℃, add 170 parts by weight of wheat bran and 18 parts by weight of Huangyuan aged vinegar brewing koji, stir evenly, and put it into a fermentation tank; when the material temperature rises naturally to 29℃, tamp the mash, cover it tightly with plastic sheeting, control the temperature in the fermentation room at 22℃, and carry out anaerobic fermentation for 5 days; after the fermentation is completed, the alcohol concentration is measured to be 5.8% vol; (2) Solid-state acetic acid fermentation: Take out the fermented material from step (1), test and adjust the alcohol concentration to 5.8% vol; add 290 parts by weight of wheat bran and 380 parts by weight of rice husk, mix evenly; enter the acetic acid fermentation stage, pour the mash once a day, control the temperature at 38℃ through heat dissipation and heat preservation measures, test the acidity regularly, and when the acidity of the vinegar no longer increases, it is the end of fermentation; at this time, add 14 parts by weight of salt, continue to pour the mash once a day, pour the mash twice in total, and then tread the mash for post-ripening; (3) Vinegar leaching and sterilization: The fermented vinegar mash is placed in a vinegar leaching tank for vinegar leaching and the vinegar liquid is collected; the vinegar liquid is heated and sterilized, and then cooled to obtain the finished product.

[0035] Example 3: This embodiment provides a process for producing aged vinegar using barley wine lees, including the following steps: (1) Fermentation of lees into solid state: Take 1000 parts by weight of barley wine lees after distillation, let it cool naturally, and when the temperature drops to 40℃, add 190 parts by weight of wheat bran and 20 parts by weight of Huangyuan aged vinegar brewing koji, stir evenly, and put it into a fermentation tank; when the temperature of the material naturally rises to 31℃, tamp the mash down, cover it tightly with plastic sheeting, control the temperature in the fermentation room at 28℃, and carry out anaerobic fermentation for 7 days; after the fermentation is completed, the alcohol concentration is measured to be 7.0% vol; (2) Solid-state acetic acid fermentation: Take out the fermented material from step (1), test and adjust the alcohol concentration to 6.2% vol; add 310 parts by weight of wheat bran and 420 parts by weight of rice husk, mix evenly; enter the acetic acid fermentation stage, pour the mash once a day, control the temperature at 42℃ through heat dissipation and heat preservation measures, test the acidity regularly, and when the acidity of the vinegar no longer increases, it is the end of fermentation; at this time, add 16 parts by weight of salt, continue to pour the mash once a day, pour the mash 3 times in total, and then tread the mash for post-ripening; (3) Vinegar leaching and sterilization: The fermented vinegar mash is placed in a vinegar leaching tank for vinegar leaching and the vinegar liquid is collected; the vinegar liquid is heated and sterilized, and then cooled to obtain the finished product.

[0036] Comparative Example 1: Compared with Example 1, the difference lies in the method of adding bran. Specifically, bran is not added in step (1), and all 480 parts by weight of bran in the formula are added together with rice husk in step (2). The proportions of other raw materials and process steps are the same.

[0037] Comparative Example 2: Compared with Example 1, the difference lies in the method of adding bran. Specifically, in step (1), all 480 parts by weight of bran in the formula are added, and in step (2), no additional bran is added. The proportions of other raw materials and the process steps are the same.

[0038] Comparative Example 3: Compared with Example 1, the difference is that the solid-state (alcoholic fermentation) process of fermenting the lees in step (1) is omitted. Specifically, the lees, Huangyuan aged vinegar brewing starter, all the bran and rice husks are mixed evenly at one time, and solid-state acetic acid fermentation is carried out directly according to the method in step (2), and the rest are the same.

[0039] Comparative Example 4: Compared with Example 1, the difference lies in the fermentation environment of step (1). Specifically, after the material is put into the fermentation tank in step (1), it is not compacted or covered with plastic sheeting. It is kept in an open and aerobic state for fermentation, while the rest is the same.

[0040] Comparative Example 5: Compared with Example 1, the difference is that the amount of rice husk added is significantly reduced. Specifically, in step (2), the amount of rice husk added is 50 parts by weight (400 parts by weight in Example 1), and the rest are the same.

[0041] Comparative Example 6: Compared with Example 1, the difference lies in the temperature control during solid acetic acid fermentation in step (2). Specifically, the product temperature is not strictly controlled; fermentation is carried out solely at room temperature (approximately 20-25°C), without any measures such as pouring the mash to dissipate heat or maintaining the temperature to 38-42°C. All other aspects remain the same.

[0042] Test Example 1: 1. Experimental Methods and Procedures: The aged vinegar products prepared in Examples 1 to 3 and Comparative Examples 1 to 6 were selected as test samples. Physicochemical indicators were determined according to the testing methods specified in GB / T18187-2000 "Brewn Vinegar" and the GB5009 series standards. Total acid content was determined by acid-base neutralization titration with phenolphthalein as an indicator, and the result was expressed as acetic acid. Non-volatile acids were determined by titration after evaporation to remove volatile acids, and the result was expressed as lactic acid. Soluble non-salt solids were determined by constant weight method, and the sodium chloride content was deducted after determining the total solids. Amino acid nitrogen was determined by formaldehyde value method. Reducing sugars were determined by Fehling's reagent direct titration method. 2. Experimental Results The physicochemical index test data of each group of samples are summarized in Table 1.

[0043] Table 1 Group Total acid (g / 100mL) Non-volatile acid (g / 100mL) Soluble salt-free solids (g / 100mL) Amino acid nitrogen (g / 100mL) Reducing sugar (g / 100mL) Example 1 6.54 2.18 22.45 0.29 2.88 Example 2 5.92 1.96 20.87 0.25 2.63 Example 3 6.71 2.23 23.14 0.31 3.02 Comparative Example 1 (without pre-fermented bran) 4.92 1.76 18.52 0.21 1.54 Comparative Example 2 (wheat bran added beforehand) 5.85 1.92 20.10 0.24 1.95 Comparative Example 3 (non-alcoholic fermentation) 4.12 1.45 16.33 0.18 1.21 Comparative Example 4 (Aerobic Pretreatment) 4.35 1.58 17.20 0.20 1.35 Comparative Example 5 (Reduction of Rice Husk) 4.65 1.68 17.91 0.20 1.48 Comparative Example 6 (without temperature control) 5.05 1.82 19.40 0.22 2.10 Based on the data analysis in Table 1, the total acid content of Examples 1 to 3 remained between 5.92 g / 100 mL and 6.71 g / 100 mL, and all indicators were better than those of Comparative Examples 1 to 6.

[0044] Comparing the data of Example 1 with Comparative Examples 1 and 2, Comparative Example 1 did not add bran during the fermentation stage of the distiller's grains, while Comparative Example 2 added all the bran in the first stage. The total acid and non-volatile acid content of the finished products of both examples were lower than those of Example 1. This indicates that adding bran in a single stage cannot simultaneously meet the nutritional needs of yeast alcohol production in the early stage and acetic acid fermentation in the later stage. The stepwise addition strategy helps maintain the microbial metabolic activity throughout the fermentation process, thereby improving the raw material conversion rate.

[0045] Comparing the data from Example 1 with those from Comparative Examples 3 and 4, Comparative Example 3 omitted the solid-state fermentation step, while Comparative Example 4 employed aerobic fermentation at this stage, resulting in a significant decrease in total acid content. This indicates that anaerobic alcoholic fermentation before acetic acid fermentation is a necessary process for accumulating ethanol precursors. Direct mixed fermentation or oxygen supply during the pretreatment stage leads to insufficient ethanol accumulation, limiting subsequent acetic acid production.

[0046] Comparing the data of Example 1 with those of Comparative Examples 5 and 6, Comparative Example 5 reduced the amount of rice husk, and Comparative Example 6 did not control the temperature; both resulted in a decrease in the physicochemical properties of the finished product. Insufficient rice husk content affected the permeability of the fermentation system and inhibited the metabolism of aerobic acetic acid bacteria; lack of temperature control led to reduced enzyme activity under low-temperature conditions and incomplete conversion of raw materials.

[0047] In summary, this invention improves the utilization rate of highland barley lees and the physicochemical properties of the finished vinegar by adding auxiliary materials in stages, controlling the oxygen environment during fermentation, and optimizing solid substrate conditions.

[0048] Test Example 2: 1. Experimental methods and procedures; Products from Examples 1 to 3 and Comparative Examples 1 to 6 were selected. The total production cycle time for each batch (using 1000 parts by weight of barley lees) was calculated, including both the solid-state fermentation and solid-state acetic acid fermentation stages. The total weight of the final aged vinegar obtained by leaching was also calculated (based on a total acidity of ≥4.5g / 100mL). Ten qualified vinegar tasters conducted blind tests according to the sensory requirements of GB / T18187-2000, scoring the samples on color, aroma, taste, and appearance, and taking the average value. 2. Experimental Results The production efficiency data and sensory score statistics for each group are shown in Table 2. Table 2 Group Alcohol content (%vol) at the end of alcoholic fermentation Total fermentation cycle (days) Finished product output (kg / batch) Sensory rating (points) Example 1 6.5 18 485 94.5 Example 2 5.8 17 462 91.2 Example 3 7.0 20 498 93.8 Comparative Example 1 4.2 21 385 81.5 Comparative Example 2 6.1 19 415 84.3 Comparative Example 3 - 22 310 74.2 Comparative Example 4 1.5 21 335 76.8 Comparative Example 5 6.0 25 360 79.5 Comparative Example 6 5.5 28 395 83.0 Comparative Example 3 did not undergo alcoholic fermentation, so there is no data on alcohol concentration; Comparative Example 4 had extremely low residual concentration due to alcohol evaporation and oxidation caused by aerobic fermentation. Based on the data analysis in Table 2, the finished product yield of Examples 1 to 3 was consistently above 460 kg, which was better than that of Comparative Examples 1 to 6.

[0049] Comparing Example 1 with Comparative Examples 1, 3, and 4, the yield differences stemmed from the substrate conversion pathway. In Example 1, Aspergillus strains degraded bran and distiller's grains starch to generate fermentable sugars during the anaerobic stage, which were then converted into ethanol by yeast, providing a precursor for acetic acid production. Comparative Example 1 lacked an initial carbon source, Comparative Example 3 lacked the ethanol conversion process, and Comparative Example 4 suffered from carbon source consumption due to the aerobic environment. All of these resulted in insufficient acetic acid precursors, thus reducing the final product yield.

[0050] Compared with Example 1, Example 2 had a higher initial ethanol concentration, but no bran was added during the acetic acid fermentation stage, resulting in a lack of nitrogen source and growth factors for the microorganisms, which led to a decrease in raw material utilization.

[0051] Regarding the fermentation cycle, Example 1 took 18 days. Comparative Example 5, due to the reduction in rice husk usage, had low material porosity and high oxygen mass transfer resistance, which limited the metabolic rate of acetic acid bacteria and prolonged the fermentation time. Comparative Example 6 lacked temperature control, and the low-temperature environment delayed enzymatic reactions and cell growth, resulting in a prolonged cycle.

[0052] In terms of sensory evaluation, the samples in the examples scored higher, which was attributed to the flavor precursors such as esters and organic acids produced during the anaerobic alcoholic fermentation stage. Comparative Example 3 omitted this process, resulting in a single flavor in the finished product. Comparative Examples 1 and 4 lacked ester precursors due to the obstruction of ethanol fermentation. Comparative Example 5 suffered from poor ventilation, which led to the generation of off-flavors and affected the sensory quality.

[0053] In summary, the process of this invention optimizes the microbial metabolic pathway and fermentation environment, thereby improving the sensory quality of the product while ensuring raw material conversion rate and production efficiency.

[0054] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A brewing composition for preparing aged vinegar using barley wine lees, characterized in that, The ingredients include the following parts by weight: 1000 parts of barley wine lees; 18-20 parts of aged vinegar brewing starter; 460-500 parts of wheat bran; 380-420 parts of rice husks; and 14-16 parts of salt.

2. The brewing composition for preparing aged vinegar using barley wine lees according to claim 1, characterized in that, The ingredients include the following parts by weight: 1000 parts of barley wine lees; 19 parts of aged vinegar brewing starter; and 480 parts of wheat bran. 400 parts rice husks; 15 parts salt.

3. The brewing composition for preparing aged vinegar using barley wine lees according to claim 1, characterized in that, The barley wine lees mentioned are solid byproducts after the solid-state fermentation and distillation of barley wine, and their water content is 60%-65%.

4. The brewing composition for preparing aged vinegar using barley wine lees according to claim 1, characterized in that, The bran is wheat bran; the rice husk is dried rice husk; and the moisture content of the fermented rice starter for aged vinegar is less than 13%.

5. A production process for preparing aged vinegar using barley wine lees, based on the brewing composition for preparing aged vinegar using barley wine lees as described in any one of claims 1-4, characterized in that, Includes the following steps: S1. Solid-state alcoholic fermentation of barley lees: Take the barley wine lees, cool them down, add the aged vinegar brewing koji and the bran from the first part, mix them evenly and put them into a fermentation container. Control the temperature of the product and the ambient temperature to carry out sealed anaerobic fermentation to obtain alcoholic fermentation mash. S2. Solid-state acetic acid fermentation and post-fermentation: Add the remaining second part of the bran and rice husk to the alcoholic fermentation mash obtained in step S1, mix evenly, and then carry out solid-state acetic acid fermentation. During the fermentation process, the mash is turned over periodically and the temperature is controlled until the acidity of the vinegar no longer increases. Then add the salt, turn the mash over evenly, seal and store for post-fermentation to obtain acetic acid fermentation mash. S3, Vinegar Leaching and Sterilization: The vinegar mash after the S2 step is fermented with vinegar, the vinegar liquid is collected, and sterilized to obtain the finished aged vinegar.

6. The production process for preparing aged vinegar using highland barley wine lees according to claim 5, characterized in that, In step S1, the bran is added in stages as follows: The amount of bran added in Part 1 is 170-190 parts by weight; In S2, the amount of bran added in the remaining second part is 290-310 parts by weight.

7. The production process for preparing aged vinegar using highland barley wine lees according to claim 5, characterized in that, The specific implementation method of S1 is as follows: Cool the barley wine lees to 36-40℃, add the aged vinegar brewing starter and the bran from the first part, and mix well. When the material temperature naturally rises to 29-31℃, compact the material and seal it tightly with plastic sheeting. Control the fermentation room temperature at 22-28℃, and the fermentation time is 5-7 days. At the end of fermentation, control the alcohol concentration at 5%vol-7%vol.

8. The production process for preparing aged vinegar using barley wine lees according to claim 5, characterized in that, In step S2, the specific implementation method of the solid-state acetic acid fermentation is as follows: The alcohol concentration of the fermented mash after step S1 was measured and adjusted to 5.8% vol - 6.2% vol. After adding the remaining bran and rice husks from the second part, the material becomes a loose solid. During fermentation, the mash is poured out once a day, and the temperature is controlled at 38-42℃. When the acidity of the vinegar juice remains stable and no longer increases, it is considered the end of fermentation.

9. The production process for preparing aged vinegar using barley wine lees according to claim 5, characterized in that, In step S2, the steps of adding salt and post-ripening are as follows: After determining the fermentation endpoint, add salt and continue to pour the mash once a day for a total of 2-3 times. Then, compact and flatten the vinegar mash, cover the surface to isolate it from air, and allow it to mature further.

10. The production process for preparing aged vinegar using barley wine lees according to claim 5, characterized in that, In step S3, the vinegar leaching is performed using a solid vinegar leaching method, which involves spraying and soaking raw vinegar juice with drinking water or secondary vinegar leaching; the sterilization is performed by heat sterilization.

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