Novel efficient multi-technology fused low-alcohol liquor fermentation process

Abstract

The invention discloses a novel efficient multi-technology fused low-alcohol liquor fermentation process, and belongs to the technical field of liquor fermentation processes. The method comprises the following steps: soaking raw materials, steaming and cooling; saccharifying the cooled raw materials; adding water into the saccharified raw materials, adding saccharomyces cerevisiae, acetobacter pasteurianus, lactic acid bacteria, caproic acid bacteria, medium-high temperature yeast and high temperature yeast, then carrying out aerobic fermentation, and then sealing for anaerobic fermentation; the fermented raw materials are settled and separated to obtain supernate and filter residues, the filter residues are subjected to filter pressing to obtain filtrate, foreshot is removed, and middle-stage wine is collected; and carrying out secondary distillation on the middle-stage wine, removing foreshot, receiving the middle-stage wine, and storing the middle-stage wine subjected to secondary distillation. The white spirit obtained by the method is harmonious in aroma, soft, sweet and mellow, and the production efficiency and the product quality stability are improved while beneficial flavor substances are reserved.

Description

Technical Field

[0001] The present invention relates to the technical field of liquor fermentation processes, and particularly to a new type of highly efficient low-alcohol liquor fermentation process integrating multiple technologies. Background Art

[0002] In the liquor industry, with the continuous improvement of consumers' requirements for health, quality, and drinking experience, the demand for young, low-alcohol, and high-quality liquor is increasing day by day. Traditional liquor brewing processes often face problems such as low substrate conversion rate, low production efficiency, high labor intensity, significant influence by the natural environment, inability to precisely control the fermentation process, and inevitable instability of liquor quality. In addition, the content of heterogenous and miscellaneous components in liquor brewed by traditional methods is generally high, which not only affects the taste balance of liquor but also may bring adverse drinking experiences such as "getting a headache" and "dry mouth", and at the same time limits the reduction of alcohol content in liquor to meet the modern trend of diversified, comfortable, and healthy products.

[0003] Some attempts have also been made in the prior art to improve the flavor of liquor and reduce fusel oils. For example, CN117844658A discloses using ester-producing yeasts JX14 and HJ31 as starting strains. Through ultraviolet mutagenesis breeding, acid resistance testing, and shake flask fermentation experiments, mutant strains J-5 and H-8 with better ester-producing performance are obtained, and the optimal combined fermentation is determined as strains JX14 and H-8. When applied to the enhanced fermentation process of rice-flavor liquor, it can increase the content of flavor substances in liquor, effectively improve the flavor of liquor, and enhance the aroma of liquor. Another example is that CN115651789A, by using the synergistic effect of traditional koji and compound functional bacteria preparations, makes the saccharification of rice more complete, improves the starch utilization rate, enhances the ability to produce liquor, acid, and aroma, greatly reduces the bitterness of liquor, and makes the aroma and taste of liquor more coordinated.

[0004] However, these methods of using microbial screening and breeding of low-fusel-oil brewing yeasts to improve the flavor of liquor still cannot achieve the purpose of improving the overall quality of liquor. The adjustment of flavor components is not deep enough, and the overall quality of liquor cannot be comprehensively improved. Summary of the Invention

[0005] Technical Problem

[0006] Currently, the content of heterogenous and miscellaneous components in liquor brewed by traditional liquor brewing processes is relatively high, and the improvement of liquor flavor in some improved processes in the prior art is not deep enough. Therefore, the overall quality of liquor still needs to be improved.

[0007] Technical Content

[0008] In order to solve the above technical problems, the present invention provides a low-alcohol liquor efficient fermentation process based on multi-technology fusion, wherein the multi-technology refers to the fine treatment of multi-formula composite raw materials, the use of modern temperature control equipment, and the combination of traditional and modern fermentation methods, and the removal of impurities and fragrance enhancement through kettle-type and pot-type composite distillation technology, wherein bay leaves, osmanthus and other auxiliary materials can also be added to increase the unique flavor, and the storage of pottery jars promotes the aging of the wine body, and the oak barrels increase the wood fragrance, flower and fruit fragrance and other technologies to jointly improve the quality and stability of the liquor. Fusion refers to the integration of raw materials, processes, microorganisms and product styles in the production of liquor. The raw material rice of rice-flavor liquor is mixed with other fragrant sorghum, glutinous rice, millet, etc., and the saccharification of Xiaoqu is combined with microorganisms such as strong-flavor caproic acid bacteria, medium-high temperature qu, and sauce-flavor high temperature qu, and modern modular microbial technology and new equipment are combined to achieve more accurate and fine production. By carefully blending the flavor characteristics of different styles of liquor, unique and charming liquor products are created to meet the taste needs of different consumers. High efficiency refers to short fermentation cycle, high starch utilization rate, and high wine yield. The preparation method of the invention is simple, can effectively improve the aroma and wine production capacity of liquor, and at the same time reduce the content of foreign components.

[0009] The present invention provides a novel process for preparing liquor, comprising the following steps:

[0010] S1. Processing of raw materials: soak the raw materials in warm water, wash the soaked raw materials with water and steam them. The raw materials after steaming should be cooked, loose, non-sticky and not undercooked, and then stand to cool;

[0011] S2, saccharification and liquefaction: adding saccharifying agent to the raw material cooled in step S1 for saccharification, ensuring air circulation but not mixing with miscellaneous bacteria;

[0012] S3, adding bacteria and koji fermentation: adding water to the saccharified raw materials, and adding brewer's yeast, acetobacter pasteurianus, lactic acid bacteria, caproic acid bacteria, medium-high temperature daqu and high temperature daqu, and then performing aerobic fermentation first and then sealing for anaerobic fermentation;

[0013] S4, filtration and distillation: the fermented raw materials are settled to separate the supernatant and the filter residue, the filter residue is filtered to obtain the filtrate, and then the supernatant and the filtrate are combined for a distillation. After removing the head, the middle section of the wine is connected to an alcohol content of 20-25°; the middle section of the wine distilled once is distilled twice in a pot still, with a reflux ratio in the range of 1.5-2 and a flow rate of 1-2 drops per second. After removing the head, the middle section of the wine is connected to an alcohol content of 40°, and the middle section of the wine distilled twice is stored.

[0014] Furthermore, the raw materials in step S1 include one or more of rice, millet, glutinous rice, and sorghum.

[0015] Preferably, the raw materials in step S1 are glutinous rice, sorghum and millet; the glutinous rice accounts for 40-60 wt% of the raw materials, the sorghum accounts for 20-40 wt% of the raw materials, and the millet accounts for 10-30 wt% of the raw materials; the selected glutinous rice can endow the wine body with a mellow and sweet taste, and the peeled sorghum has fewer impurities. The selected peeled sorghum and millet are used in combination, which can endow the wine body with a mellow and clean quality.

[0016] Further, the raw materials in step S1 can be raw materials that have been baked or crushed; baking can promote the occurrence of Maillard and caramelization reactions inside the grains, making the wine body have a baking aroma; crushing the raw materials can increase the contact area with Rhizopus, reduce the saccharification time, improve the liquor yield, and make the starch utilization rate higher.

[0017] Further, the baking is to place rice in a roasting machine and bake it at 170-180 °C for 20-30 min to obtain baked rice.

[0018] Further, the crushing is to crush rice using a crusher and pass through a 10-30 mesh sieve to obtain crushed rice.

[0019] Further, the water temperature of the warm water in step S1 is 30-40 °C.

[0020] Further, the soaking time in step S1 is 2-5 hours.

[0021] Further, the steaming of the raw materials in step S1 is carried out using a steamer, and the steaming time is 0.5-1 hour.

[0022] Further, the cooling temperature in step S1 is 40-45 °C.

[0023] Further, the saccharifying agent in step S2 is one or two of Rhizopus and enzyme preparation.

[0024] Further, the enzyme preparation is a mixture of amylase and protease with a mass ratio of 1:0.5-1.5.

[0025] Preferably, the saccharifying agent in step S2 is a mixture of Rhizopus and enzyme preparation.

[0026] Preferably, the addition amount of Rhizopus is 0.8-1.2 wt% of the dry weight of the raw materials.

[0027] Preferably, the addition amount of the enzyme preparation is 0.3-0.7 wt% of the dry weight of the raw materials.

[0028] Further, the saccharification time in step S2 is 30-40 hours.

[0029] Preferably, the saccharification time in step S2 is 34-38 hours.

[0030] Most preferably, the saccharification time in step S2 is 36 hours; the preferred saccharification time can maximize the conversion of starch in the raw materials into fermentable sugars, which are the nutrients required for yeast fermentation, thereby increasing the liquor yield.

[0031] Furthermore, the saccharification temperature in step S2 is 25 - 32 °C.

[0032] Furthermore, the mass of water in step S3 is 3 - 6 times the dry weight of the raw materials.

[0033] Furthermore, the addition amount of Saccharomyces cerevisiae in step S3 is 0.6 - 1 wt% of the dry weight of the raw materials.

[0034] Furthermore, the addition amount of Acetobacter pasteurianus in step S3 is 0.1 - 0.3 wt% of the dry weight of the raw materials.

[0035] Furthermore, the addition amount of lactic acid bacteria in step S3 is 0.1 - 0.3 wt% of the dry weight of the raw materials.

[0036] Furthermore, the addition amount of Caproic acid bacteria in step S3 is 0.1 - 0.3 wt% of the dry weight of the raw materials.

[0037] Furthermore, the addition amount of medium and high temperature Daqu in step S3 is 0.3 - 0.7 wt% of the dry weight of the raw materials.

[0038] Furthermore, the addition amount of high temperature Daqu in step S3 is 0.3 - 0.7 wt% of the dry weight of the raw materials.

[0039] Specifically, optionally, in step S3, based on the dry weight of the raw materials, the addition amount of Saccharomyces cerevisiae is 0.8 wt%; the addition amount of Acetobacter pasteurianus is 0.2 wt%; the addition amount of lactic acid bacteria is 0.2 wt%; the addition amount of Caproic acid bacteria is 0.2 wt%; the addition amount of medium and high temperature Daqu is 0.5 wt%; the addition amount of high temperature Daqu is 0.5 wt%; the raw materials are fermented by the synergistic strains, which not only endows the liquor body with a compound grain aroma but also increases the baking aroma, making the liquor body more fragrant, pure, and able to better gain the favor of consumers.

[0040] Furthermore, the temperature of aerobic fermentation in step S3 is 25 - 30 °C, and the time is 1 - 2 days.

[0041] Furthermore, the temperature of anaerobic fermentation in step S3 is 25 - 30 °C, and the time is 6 - 7 days.

[0042] Furthermore, the pressure range of the first distillation in step S4 is 0.15 - 0.2 MPa, and the distillation temperature is 70 - 75 °C.

[0043] Further, the volume (L) of the heads removed during the first distillation in step S4 is 10-15% of the mass (kg) of the raw materials used in S1.

[0044] Further, the pressure range for the secondary distillation in step S4 is 0.005-0.012 MPa, and the boiling point of the distillate is 80-85 °C. Pot still distillation is used for the secondary distillation, which can further enrich the aroma substances, endow it with a highly complex fragrance, and at the same time significantly reduce the contents of active amyl alcohol and isoamyl alcohol in the distillate, reducing the influence of foreign and off-flavor substances on the characteristic flavor of the liquor.

[0045] Further, the volume (L) of the heads removed during the secondary distillation in step S4 is 15-20% of the mass (kg) of the raw materials used in S1.

[0046] Further, for the storage in step S4, storage can be carried out using earthenware jars or oak barrels; or first using earthenware jars for storage and then using oak barrels for storage; or first using oak barrels for storage and then using earthenware jars for storage; the storage time is 6 months to 3 years. The air permeability of the earthenware jars promotes the aging process of the liquor, increasing the aged flavor. The oak barrels can endow the liquor with rich fragrances such as wood, vanilla, cream, and chocolate, making the liquor body plump and the aroma more intense. The combined use of earthenware jars and oak barrels enables the liquor to draw on the advantages of both during storage, forming a more unique and rich flavor. The storage order of the earthenware jars and oak barrels can be changed, and different combinations of storage times can be adopted to form base liquors with different styles.

[0047] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0048] (1) By integrating technologies such as high-efficiency enzyme preparations, selected modular functional microorganisms, precise control of the fermentation process, a production data management system, and precise distillation, the present invention stabilizes the fermentation environment, reduces the influence of climate and environmental changes on the fermentation process, and the liquor body has a harmonious aroma, is mellow and sweet.

[0049] (2) The present invention adopts secondary distillation. By precisely controlling the distillation process and optimizing the parameter settings during distillation, the effects of effectively removing foreign and off-components and retaining beneficial flavor substances are achieved, and the production efficiency and product quality stability are improved. Description of the Drawings

[0050] Figure 1 Curves related to the alcohol content, active amyl alcohol, isoamyl alcohol, and secondary distillation time in Example 2. Detailed Embodiments

[0051] The following clearly and completely describes each technical solution of the present invention in combination with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by other technical personnel in the field without creative work belong to the scope protected by the present invention. The equivalent transformation or substitution of methods, process routes, and functions made by those skilled in the art according to the following embodiments all fall within the scope of protection of the present invention.

[0052] Raw material source

[0053] Rhizopus sp was purchased from China Center of Industrial Culture Collection (CICC), and the preservation number is CICC40260; Saccharomyces cerevisiae was purchased from China Center of Industrial Culture Collection (CICC), and the preservation number is CICC 1307; Acetobacter pasteurianus was purchased from China Center of Industrial Culture Collection (CICC), and the preservation number is CICC 20001; Pediococcus acidilactici was purchased from China Center of Industrial Culture Collection (CICC), and the preservation number is CICC 24367; Caproicibacterium sp. was purchased from China Center of Industrial Culture Collection (CICC), and the preservation number is CICC 24509; Amylase ≥3.500u / mg, CAS number: 9000-92-4, was purchased from Shanghai Yuanye Bio-Technology Co., Ltd.; Protease 50u / mg, CAS number: 9068-59-1, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; Medium-high temperature Daqu and high temperature Daqu are from the koji-making workshop of Jiangsu Yanghe Brewery Co., Ltd.

[0054] Example 1

[0055] S1. Raw material pretreatment: Take 0.5 kg of baked rice + 0.5 kg of crushed rice as raw materials, soak them with water at 30-40 °C. When soaking, add warm water first and then the raw materials, and stir them. After stirring, keep the water temperature and let the grains soak for 2 h.

[0056] Preparation of baked rice: Place the rice in a roasting machine and bake it at 180 °C for 30 min to obtain baked rice.

[0057] Preparation of crushed rice: Take the rice and crush it with a crusher, and sieve it through a 20-mesh sieve to obtain crushed rice.

[0058] S2, Cooking and Cooling: Wash the soaked raw materials 2 - 3 times with water, spread them out evenly in the steamer, steam the materials over high heat for 0.5 - 1 h. The state of the cooked raw materials should be thoroughly cooked, loose, non-sticky and without being undercooked, and then cool them down to about 40°C.

[0059] S3, Saccharification and Liquefaction: Transfer the cooled raw materials to the saccharification equipment for culturing and saccharification. Add Rhizopus with a mass of 1.5 wt% relative to the dry weight of the raw materials and carry out saccharification at 30°C for 36 h, ensuring air circulation without mixing in miscellaneous bacteria.

[0060] S4, Adding Bacteria and Fermenting with Qu: After saccharification, add 5 times the mass of pure water relative to the dry weight of the raw materials and transfer them to a vertical fermentation tank. Add Saccharomyces cerevisiae with a mass of 1.6 wt% and medium-high temperature Daqu with a mass of 0.8 wt% relative to the dry weight of the raw materials, and carry out modular fermentation with aerobic first and then anaerobic sealing. Among them, the fermentation temperature is maintained at 26°C, the aerobic fermentation time is 1 day, and the anaerobic sealed fermentation time is 6 days, for a total of 7 days.

[0061] S5, Filtration and Distillation: Transfer the raw materials in the fermentation tank to a settling tank for settling for 12 h, separate to obtain the supernatant and filter residue. Use a filter press to press the filter residue to obtain filtrate. Then transfer the supernatant and filtrate to a distillation kettle for the first distillation. The pressure range is 0.15 - 0.2 MPa, and the distillation temperature is 75°C. After slowly distilling off 0.1 L of the head of the liquor, collect the middle section of the liquor until the alcohol content reaches 20°, and then start collecting the tail of the liquor until the alcohol content reaches 10°; The middle section of the liquor obtained from the first distillation is subjected to a second distillation using a pot still. Control the pressure range to be 0.005 - 0.012 MPa, the boiling point of the distillate is 83°C, the reflux ratio range is 1.5 - 2, and the flow rate is preferably 1 - 2 drops per second. The first 0.2 L of the liquor is the head of the liquor, then collect the middle section of the liquor. When the alcohol content drops to 40°, start collecting the tail of the liquor. When the alcohol content drops to 10°, stop collecting the liquor; The heads and tails of the liquor from the two distillations are transferred to a separate storage container for storage and used for the next fermentation liquid distillation.

[0062] S6, Storage: Put the middle section of the liquor with different alcohol contents after the second distillation into earthen jars for storage for 6 months for blending.

[0063] Example 2

[0064] S1, Raw Material Pretreatment: Take 0.5 kg of glutinous rice + 0.3 kg of shelled sorghum + 0.2 kg of millet as raw materials, soak them in water at 30 - 40°C. When soaking, first add warm water and then the raw materials, and stir them. After stirring, keep the water temperature and let the grains soak for 2 h.

[0065] S2, Cooking and Cooling: Wash the soaked raw materials 2 - 3 times with water, spread them out evenly in the steamer, steam the materials over high heat for 0.5 - 1 h. The state of the cooked raw materials should be thoroughly cooked, loose, non-sticky and without being undercooked, and then cool them down to about 40°C.

[0066] S3. Saccharification and Liquefaction: After cooling, transfer to saccharification equipment for culturing and saccharification. Add 1 wt% Rhizopus and 0.5 wt% enzyme preparation (0.25 wt% amylase + 0.25 wt% protease) based on the dry weight of the raw materials for saccharification for 36 h, ensuring air circulation without contamination by miscellaneous bacteria.

[0067] S4. Adding Bacteria and Fermenting with Qu: After saccharification, supplement with 5 times the mass of pure water based on the dry weight of the raw materials and transfer to a vertical fermenter. Add 0.8 wt% Saccharomyces cerevisiae, 0.2 wt% Acetobacter pasteurianus, 0.2 wt% Lactobacillus, 0.2 wt% Clostridium acetobutylicum, 0.5 wt% medium-high temperature Daqu, and 0.5 wt% high temperature Daqu based on the dry weight of the raw materials for modular fermentation with aerobic first and then anaerobic sealing. The fermentation temperature is maintained at 26 °C, the aerobic fermentation time is 1 day, and the anaerobic sealed fermentation time is 6 days, for a total of 7 days.

[0068] S5. Filtration and Distillation: Transfer the raw materials in the fermenter to a sedimentation tank for sedimentation for 12 h, then separate to obtain the supernatant and filter residue. Use a filter press to filter the filter residue to obtain filtrate. Then transfer the supernatant and filtrate to a distillation kettle for the first distillation, with the pressure range of 0.15 - 0.2 MPa and the distillation temperature of 75 °C. After slowly distilling off 0.1 L of the heads, collect the middle-run liquor until the alcohol content reaches 20°, and then start collecting the tails until the alcohol content reaches 10°. The middle-run liquor obtained from the first distillation is subjected to a second distillation using a pot still, controlling the pressure range of 0.005 - 0.012 MPa, the boiling point of the distillate is 83 °C, the reflux ratio range is 1.5 - 2, and the flow rate is preferably 1 - 2 drops per second. The first 0.2 L of the liquor is the heads, then collect the middle-run liquor. When the alcohol content drops to 40°, start collecting the tails. When the alcohol content drops to 10°, stop collecting. The heads and tails from the two distillations are transferred to a separate storage container for storage and used for the next fermentation liquor distillation.

[0069] S6. Storage: Put the middle-run liquor with different alcohol contents after the second distillation into earthen jars for storage for 6 months for blending.

[0070] Comparative Example 1

[0071] S1. Raw Material Pretreatment: Take 1 kg of rice as the raw material and soak it in water at 30 - 40 °C. When soaking, first add warm water and then the raw material, and stir it. After stirring, keep the water temperature and let the grains soak for 2 h.

[0072] S2. Cooking and Cooling: Wash the soaked raw materials 2 - 3 times with water, put them in a steamer and spread them out flat, steam the materials over high heat for 0.5 - 1 h. The state of the cooked raw materials should be fully cooked, loose, not sticky, and without being undercooked, and cool them to about 40 °C.

[0073] S3. Saccharification and Liquefaction: After cooling, transfer to saccharification equipment for culturing and saccharification. Add 1.5 wt% Rhizopus based on the dry weight of the raw materials for saccharification for 36 h, ensuring air circulation without contamination by miscellaneous bacteria.

[0074] S4, Adding bacteria and koji for fermentation: After saccharification, add pure water five times the dry weight of the raw materials and transfer it to a vertical fermentation tank. Add 1.6 wt% of Saccharomyces cerevisiae and 0.8 wt% of medium and high temperature Daqu based on the dry weight of the raw materials, and carry out modular fermentation with aerobic first and then anaerobic sealing. The fermentation temperature is maintained at 26 °C, the aerobic fermentation time is 1 day, and the anaerobic sealed fermentation time is 6 days, totaling 7 days;

[0075] S5, Filtration and distillation: Transfer the raw materials in the fermentation tank to a sedimentation tank for sedimentation for 12 h, then separate to obtain the supernatant and filter residue. Use a filter press to filter the filter residue to obtain filtrate. Then transfer the supernatant and filtrate to a distillation kettle for the first distillation. The pressure range is 0.15 - 0.2 MPa, and the distillation temperature is 75 °C. After slowly distilling off 0.1 L of the head liquor, collect the middle liquor until the alcohol content reaches 20°, and then start collecting the tail liquor until the alcohol content reaches 10°; The middle liquor obtained from the first distillation is subjected to a second distillation using a pot still. Initially, control the pressure range at 0.005 - 0.012 MPa, the boiling point of the distillate is 83 °C, the reflux ratio range is about 1.5 - 2, and the flow rate is optimally 1 - 2 drops per second. The first 0.2 L of the liquor is the head liquor, then collect the middle liquor. When the alcohol content drops to 40°, start collecting the tail liquor. When the alcohol content drops to 10°, stop collecting the liquor; The head liquor and tail liquor from the two distillations are transferred to separate storage containers for storage and used for the distillation of the next fermentation broth;

[0076] S6, Storage: Put the middle liquor with different alcohol contents after the second distillation into earthen jars for storage for 6 months for blending.

[0077] Comparative Example 2

[0078] Refer to Example 2, and adjust the bacteria and koji added in step S4 specifically as follows: Add 0.8 wt% of Saccharomyces cerevisiae, 0.1 wt% of Acetobacter pasteurianus, 0.1 wt% of Lactobacillus, 0.2 wt% of Caproic acid bacteria, 0.25 wt% of medium and high temperature Daqu, and 0.5 wt% of high temperature Daqu based on the dry weight of the raw materials, and keep other parameters and operations unchanged.

[0079] Comparative Example 3

[0080] Refer to Example 2, and adjust step S5 to only perform one distillation specifically as follows: Transfer the raw materials in the fermentation tank to a sedimentation tank for sedimentation for 12 h, then separate to obtain the supernatant and filter residue. Use a filter press to filter the filter residue to obtain filtrate. Then transfer the supernatant and filtrate to a distillation kettle for the first distillation. The pressure range is 0.15 - 0.2 MPa, and the distillation temperature is 75 °C. After slowly distilling off 0.1 L of the head liquor, collect the middle liquor until the alcohol content reaches 20°, then start collecting the tail liquor until the alcohol content reaches 10°, and stop collecting the liquor.

[0081] Comparative Example 4

[0082] It is carried out with reference to Example 2, in which the bacteria and koji added in step S4 are adjusted. Specifically, 0.8 wt% of Saccharomyces cerevisiae, 0.6 wt% of Acetobacter pasteurianus, 0.5 wt% of medium-high temperature Daqu, and 0.5 wt% of high temperature Daqu are added based on the dry weight of the raw materials, and other parameters and operations remain unchanged.

[0083] Comparative Example 5

[0084] It is carried out with reference to Example 2, in which the bacteria in step S3 are adjusted. Specifically, 1 wt% of Rhizopus is added for saccharification for 36 h based on the dry weight of the raw materials, and other parameters and operations remain unchanged.

[0085] Comparative Example 6

[0086] It is carried out with reference to Example 2, in which the additives in step S3 are adjusted. Specifically, 1 wt% of Rhizopus + 0.5 wt% of enzyme preparation (0.25 wt% of amylase + 0.25 wt% of protease) are added for saccharification for 24 h based on the dry weight of the raw materials, and other parameters and operations remain unchanged.

[0087] Comparative Example 7

[0088] It is carried out with reference to Example 2, in which the parameters of the secondary distillation in step S5 are adjusted. Specifically, the initial pressure control range is 0.02 - 0.04 MPa, the boiling point of the distillate is 81.5 °C, the reflux ratio range is about 1.5 - 2, and the flow rate is preferably 1 - 2 drops per second, and other parameters and operations remain unchanged.

[0089] Comparative Example 8

[0090] It is carried out with reference to Example 2, in which the storage container in step S6 is adjusted. Specifically, the middle-section liquor of different degrees after secondary distillation is put into an oak barrel for storage for 6 months for blending.

[0091] 1. Calculate the liquor yield of each example and comparative example, as shown in Table 1:

[0092] Table 1 Liquor Yield of Samples

[0093]

[0094]

[0095] Note: The liquor yield is converted based on 50°vol.

[0096] It can be seen from the results in Table 1 that the liquor yield of the examples of the present invention is relatively high, indicating that its starch utilization rate is higher. By comparing Example 1 and Comparative Example 1, it is found that crushing the raw materials can appropriately increase the liquor yield. At the same time, from the results of Example 2, it can be seen that adding glutinous rice to the raw materials can make the starch gelatinization more complete and further improve the alcohol conversion rate.

[0097] In addition, by comparing Example 2 with Comparative Examples 2 to 6, it can be seen that optimizing key parameters such as the addition amount of enzyme preparation, the ratio of koji materials, and the saccharification time can significantly increase the liquor yield.

[0098] 2. Detect the differences in flavor substances of each example and comparative example: Use a gas chromatograph to detect the flavor substances in the middle-section liquor prepared in each example and comparative example. The detection parameters of the gas chromatograph are set as follows: carrier gas N2, flow rate 1 mL / min, inlet temperature 270 °C, injection volume 1 μL, split ratio 50:1, cp-wax57CB type (cp-97723A) capillary chromatographic column, 50 m * 0.25 mm * 0.25 μm; programmed temperature rise, hold at 35 °C for 6 min, increase the temperature to 60 °C at a rate of 6 °C / min, hold for 3 min, then increase the temperature to 80 °C at a rate of 4.5 °C / min, hold for 2 min, increase the temperature to 180 °C at a rate of 9.5 °C / min, hold for 2 min, increase the temperature to 210 °C at a rate of 9.5 °C / min, hold for 10 min; FID detector, 300 °C, H2 flow rate 30 mL / min, air flow rate 300 mL / min. The detection results are shown in Table 2 below:

[0099] Table 2 Content of flavor substances in Baijiu

[0100]

[0101]

[0102] As can be seen from Table 2, it can be clearly observed that the contents of ethyl acetate and ethyl lactate in Example 2 are significantly higher than those in other groups, while the contents of active amyl alcohol and isoamyl alcohol are maintained at a relatively low level. As Figure 1 shown, at 0 min, the content of active amyl alcohol + isoamyl alcohol is about 400 mg / L, but after 20 min, the content of active amyl alcohol + isoamyl alcohol decreases to less than 200 mg / L. The experimental data show that compared with Comparative Examples 3 and 7, by optimizing the distillation pressure range and reflux ratio, the contents of active amyl alcohol and isoamyl alcohol can be significantly reduced (the reduction rate reaches 20-40%). This result directly confirms that the secondary distillation process plays a decisive role in reducing the content of fusel alcohols and improving the purity of the liquor body. At the same time, the parameter settings in the secondary distillation are also crucial for the effect of the secondary distillation.

[0103] Comparing Example 2 with Comparative Examples 5 and 6, it can be found that appropriate saccharification time and the use of enzyme preparations during saccharification can promote the formation of characteristic flavor substances in the wine body. Comparing Example 2 with Comparative Examples 2 and 4, it can be found that the component ratio of the composite acid-producing bacteria also plays an important role in the formation of characteristic flavor substances in the wine body. In Comparative Example 1, only medium and high-temperature Daqu was relied on and although the saccharification time was sufficient, the contents of ethyl acetate and ethyl lactate could not be effectively increased, and the contents of these flavor substances were significantly lower than those of other examples. This shows that the saccharification time and the synergistic effect of multiple strains have an important influence on optimizing the flavor of the wine body.

[0104] 3. Sensory evaluation: The middle-section wines prepared in Example 1, Example 2 and Comparative Examples 1-8 were subjected to sensory evaluation. The samples were blindly labeled with three random digits to avoid subjective tendency. The wine samples were adjusted to a uniform temperature (20±1°C), and left standing for 24 hours to eliminate bubbles and volatile differences. Each sample was quantified (30-50 mL) and dispensed into colorless transparent glass cups with the same liquid level height (1-2 cm from the cup mouth). Sensory evaluation was carried out by comprehensively considering the aroma, taste characteristics, and whether there were any off-flavors. The evaluation results are shown in Table 3 below:

[0105] Table 3 Sensory evaluation form

[0106] Group Evaluation result Example 1 Soft, sweet and mellow, rich in baking aroma, clean aftertaste and long-lasting flavor Example 2 Soft, sweet and mellow, rich in fruity and floral aroma, harmonious fragrance, complex grain fragrance, clean aftertaste and long-lasting flavor Comparative example 1 Soft and sweet, slightly bitter aftertaste Comparative example 2 Soft, sweet and mellow, complex grain fragrance, rich in fruity and floral aroma, bitter aftertaste Comparative example 3 Soft, sweet and mellow, rich in fruity and floral aroma, complex grain fragrance, clean aftertaste and long-lasting flavor Comparative example 4 Soft and sweet, strong sour taste, bitter aftertaste Comparative example 5 Soft, sweet and mellow, complex grain fragrance, bitter aftertaste Comparative example 6 Soft, sweet and mellow, complex grain fragrance, bitter aftertaste Comparative example 7 Soft, sweet and mellow, rich in fruity and floral aroma, harmonious fragrance, complex grain fragrance, slightly bitter aftertaste Comparative example 8 Strong sweet feeling, rich in fruity and woody aroma, harmonious fragrance, prominent sweet aftertaste

[0107] As can be seen from Table 3, compared with Comparative Example 1, the wine bodies of Example 1 are both mellow and sweet. The wine body of Example 1 is more mellow and has a strong baking aroma, while the coordination between the aroma and taste of the wine body in Comparative Example 1 is weaker. Comparing Comparative Example 3 (single distillation process) and Comparative Example 7 (adjusting the pressure range) with Example 2, the wine body of Example 2 has better flavor coordination, lower contents of active amyl alcohol and isoamyl alcohol, and can moderately solve problems such as bitterness and headache. There are problems of bitter aftertaste in Comparative Examples 2 and 4-6, which may be caused by improper ratios of bacteria and molds, saccharification time, etc. Comparing Comparative Example 8 with Example 2, the wine body of Comparative Example 8 shows an amber color, and compared with traditional Chinese liquor, it has a softer and more delicate taste, and different storage containers can be selected according to requirements.

[0108] The examples provided above are not intended to limit the scope covered by the present invention, and the described steps are not intended to limit their execution order. Obvious improvements made by those skilled in the art to the present invention in combination with the existing common general knowledge also fall within the protection scope defined by the claims of the present invention.

Claims

1. A novel process for preparing Chinese liquor, characterized in that, It includes the following steps: S1. Treatment of raw materials: Take the raw materials and soak them in warm water. After soaking, wash the raw materials with water and then steam them. The state of the steamed raw materials should be thoroughly cooked, loose, non-sticky and without being undercooked, and then let them stand still to cool down; S2. Saccharification and liquefaction: Add saccharifying agents to the raw materials cooled in step S1 for saccharification, ensuring air circulation but no foreign bacteria are mixed in; S3. Adding bacteria and koji for fermentation: Add water to the saccharified raw materials, and add Saccharomyces cerevisiae, Acetobacter pasteurianus, Lactobacillus, Caproic acid bacteria, medium-high temperature Daqu and high temperature Daqu, and then first carry out aerobic fermentation and then seal for anaerobic fermentation; Based on the dry weight of the raw materials, the addition amount of Saccharomyces cerevisiae is 0.6 - 1 wt%, the addition amount of Acetobacter pasteurianus is 0.1 - 0.3 wt%, the addition amount of Lactobacillus is 0.1 - 0.3 wt%, the addition amount of Caproic acid bacteria is 0.1 - 0.3 wt%, the addition amount of medium-high temperature Daqu is 0.3 - 0.7 wt%, and the addition amount of high temperature Daqu is 0.3 - 0.7 wt%; S4. Filtration and distillation: Let the fermented raw materials settle, separate to obtain the supernatant and filter residue, press the filter residue to obtain the filtrate, and then combine the supernatant and the filtrate for the first distillation. After removing the heads, collect the middle section of the liquor until the alcohol degree reaches 20 - 25°. Carry out the second distillation of the middle section of the liquor from the first distillation using a pot still. The pressure range for the second distillation is 0.005 - 0.012 MPa, the boiling point of the distillate is 80 - 85 °C, the reflux ratio is 1.5 - 2, the flow rate is 1 - 2 drops per second. After removing the heads, collect the middle section of the liquor until the alcohol degree reaches 40°, and store the middle section of the liquor after the second distillation; 2. The white liquor preparation process according to claim 1, wherein The raw materials described in step S1 include one or more of rice, millet, glutinous rice, and sorghum.

3. According to the white liquor preparation process described in claim 1, it is characterized in that, The saccharifying agent in step S2 is a mixture of Rhizopus and enzyme preparations; the enzyme preparations are a mixture of amylase and protease with a mass ratio of 1:0.5 - 1.

5.

4. The white liquor preparation process according to claim 3, characterized in that, The saccharifying agent in step S2 is a mixture of Rhizopus and enzyme preparations; the addition amount of Rhizopus is 0.8 - 1.2 wt% of the dry weight of the raw materials; the addition amount of the enzyme preparations is 0.3 - 0.7 wt% of the dry weight of the raw materials.

5. The white liquor preparation process according to claim 1, characterized in that, The saccharification time in step S2 is 30 - 40 hours, and the saccharification temperature is 25 - 32 °C.

6. The white liquor preparation process according to claim 1, characterized in that, Based on the dry weight of the raw materials, the addition amount of Saccharomyces cerevisiae is 0.8 wt%; the addition amount of Acetobacter pasteurianus is 0.2 wt%; the addition amount of Lactobacillus is 0.2 wt%; the addition amount of Caproic acid bacteria is 0.2 wt%; the addition amount of medium-high temperature Daqu is 0.5 wt%; the addition amount of high temperature Daqu is 0.5 wt%.

7. The liquor preparation process according to claim 1, characterized in that, The temperature of the aerobic fermentation in step S3 is 25 - 30 °C, and the time is 1 - 2 days. The temperature of the anaerobic fermentation is 25 - 30 °C, and the time is 6 - 7 days.

8. The liquor preparation process according to claim 1, characterized in that, The pressure range for the first distillation in step S4 is 0.15 - 0.2 MPa, and the distillation temperature is 70 - 75 °C; the volume L of the heads removed in the first distillation is 10 - 15% of the mass kg of the raw materials used in S1.

9. The liquor preparation process according to claim 1, wherein The volume L of the heads removed in the second distillation in step S4 is 15 - 20% of the mass kg of the raw materials used in S1.

10. The white liquor preparation process according to claim 1, characterized in that, The storage described in step S4 can be carried out using earthenware jars or oak barrels; or first stored in earthenware jars and then in oak barrels; or first stored in oak barrels and then in earthenware jars; the storage time is 6 months to 3 years.

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