Brewing method for improving content of ethyl hexanoate in northern Luzhou-flavor liquor and application of brewing method in intelligent brewing

Abstract

The invention discloses a brewing method for improving the content of ethyl hexanoate in northern Luzhou-flavor liquor, which comprises the following steps of: in a large-cellar brewing process of northern Luzhou-flavor liquor, adding a double-enzyme solution obtained by mixing lipase and acid protease into a cellar in a process of fermenting in the cellar; the double-enzyme liquid is controlled to be added to a position which is not more than 1 / 4 of the height of the pit from the bottom of the pit, so that the ethyl hexanoate content of the raw wine is increased. According to the improved brewing process, the content of ethyl hexanoate in brewed raw wine can be greatly increased, the product quality of Luzhou-flavor liquor brewed in a large cellar is improved, the strong style characteristic of typical northern Luzhou-flavor liquor is kept, and according to the brewing method, a control program of an intelligent brewing process can be developed; and application and development of intelligent brewing are promoted.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of liquor brewing process, in particular to a brewing method for increasing the content of ethyl hexanoate in northern strong-flavor liquor, and application of the method in intelligent brewing process of strong-flavor liquor. BACKGROUND

[0002] With the iteration and upgrading of intelligent technology, the production mode of deep integration of mechanization and intelligence is reshaping the traditional industrial pattern in a revolutionary way. In the field of liquor brewing, this trend is showing explosive development, such as intelligent temperature control system based on AI algorithm, automatic koji-making equipment integrating Internet of Things technology, which are gradually penetrating into a series of core brewing links such as raw material processing, fermentation monitoring, and distillation. Compared with the traditional labor-intensive operation mode of temperature and humidity management relying on experience control and manual stirring of fermented grains, intelligent brewing technology realizes full-process data collection through sensor network and completes standardized operation relying on industrial robots, which not only can improve the stability and accuracy of production, but also can optimize production efficiency, reduce labor intensity and cost; but the prerequisite for intelligent brewing is that the cellar should be large, generally more than 20 cubic meters. Compared with traditional small cellar brewing, the quality of raw liquor may decrease in large cellar brewing.

[0003] Specifically, on the one hand, the microbial metabolism in small cellar (usually 8-15 cubic meters) is more concentrated, and the contact area between pit mud and grain in unit volume is more, which is more conducive to the reproduction and metabolism of functional microorganisms such as caproic acid bacteria and butyric acid bacteria in pit mud, generating more main aroma components of strong-flavor liquor, ethyl hexanoate; on the other hand, the temperature of small cellar is easy to control, and the heat is easy to disperse uniformly during fermentation, avoiding local overheating leading to the breeding of miscellaneous bacteria. Therefore, the brewing process of large cellar generally has the problem of less generation of ethyl hexanoate, thereby reducing the cellar aroma of raw liquor, making the taste light and uncoordinated, and obviously affecting the quality of raw liquor.

[0004] Currently, the industry usually adopts the methods of prolonging fermentation period and mud fermentation to increase the content of ethyl hexanoate in raw liquor, but prolonging fermentation period will reduce the efficiency of intelligent brewing, and mud fermentation will increase the smell of mud. Some enterprises can only weaken or cancel the requirement of ethyl hexanoate content. In order to maintain the typicality and strong-flavor style of northern strong-flavor liquor (i.e. northern school, mainly concentrated in the North China Plain region, different from Sichuan school and Jianghuai school), effectively solving the problem of low production of ethyl hexanoate is a technical bottleneck that needs to be solved in intelligent brewing technology. SUMMARY

[0005] The present application is directed to the problem of affecting the ethyl hexanoate content of base liquor in the process of large pit brewing northern strong-flavor liquor, proposes a brewing process which directly adds lipase and acid protease double enzyme liquid to the pit in the pit fermentation process and controls the adding position of the double enzyme liquid, and further optimizes the composition of the double enzyme liquid, the distillation speed, the saccharifying power of Daqu, the temperature and moisture content of the fermented grains entering the pit, etc., to significantly improve the ethyl hexanoate content of the brewed base liquor, and further improve the quality of northern strong-flavor liquor.

[0006] To achieve the above-mentioned purpose, the present application provides a brewing method for improving the ethyl hexanoate content in northern strong-flavor liquor, which is to add double enzyme liquid obtained by mixing lipase and acid protease to the pit in the pit fermentation process of northern strong-flavor liquor, and control the adding position of the double enzyme liquid to a position not more than one quarter of the pit height from the pit bottom, to improve the ethyl hexanoate content of the base liquor.

[0007] Based on a large number of production tests, according to the esterification mechanism of enzymes in the brewing process of strong-flavor liquor and the reaction and contact state between ethanol, hexanoic acid, water, pit mud and other substances in the fermentation process of the pit, the present application proposes a brewing improvement process which directly adds double enzyme liquid composed of lipase and acid protease to the pit and controls the adding position, which realizes significantly improving the ethyl hexanoate content of the base liquor and improving the product quality of large pit brewing northern strong-flavor liquor without changing the brewing process and increasing the production cost.

[0008] As a limitation of the above technical solution, the mass ratio of lipase to acid protease in the double enzyme liquid is 1:30-40, and further preferably 1:40.

[0009] As a limitation of the above technical solution, in the upper distillation and grain distillation process of the large pit brewing process, the distillation speed is controlled to be not more than 2.5 kg / min, and further preferably 2.0-2.5 kg / min.

[0010] As a limitation of the above technical solution, in the spreading and airing of the lower koji process of the large pit brewing process, Daqu with a saccharifying power of 700-900 U / g is added, and further preferably Daqu with a saccharifying power of 700-800 U / g.

[0011] As a limitation of the above technical solution, in the spreading and airing of the lower koji process of the large pit brewing process, the temperature of the fermented grains entering the pit is controlled to be 18-22℃, and further preferably the temperature of the fermented grains entering the pit is controlled to be 18-20℃.

[0012] As a limitation of the above technical solution, in the spreading and airing of the lower koji process of the large pit brewing process, the moisture content of the fermented grains is controlled to be 56-57%.

[0013] As a limitation of the above technical solution, the ethyl hexanoate content of the base liquor is not less than 1.6 g / L.

[0014] As a limitation of the above technical solutions, the capacity of the large cellar is more than 20 cubic meters.

[0015] The brewing process of the present application further optimizes the ratio of the double enzyme liquid, controls the distillation speed, the saccharifying power of the large-koji, the temperature and moisture content of the grain mash entering the cellar, so that the ethyl hexanoate content of the raw liquor can be increased by more than 30%, and the style characteristics of the typical northern strong-flavor liquor are maintained.

[0016] Meanwhile, the present application also provides the application of the brewing method for increasing the ethyl hexanoate content in the northern strong-flavor liquor in intelligent brewing, i.e. the brewing method is used for the development and application of the control program of the intelligent brewing process.

[0017] In addition, the present application also provides a computer-readable storage medium, i.e. one or more program instructions are contained, which, when running on a computer, make the computer execute the brewing method as described above.

[0018] The improved brewing process of the strong-flavor liquor according to the present application is beneficial to the development and application of the control program of the intelligent brewing process and related products, and has a positive promoting effect on the intelligent development of the liquor brewing industry.

[0019] In summary, according to the esterification mechanism of the enzyme in the brewing process of the strong-flavor liquor and the reaction and contact state among ethanol, hexanoic acid, moisture, pit mud and other substances in the fermentation process of the cellar, the present application proposes an improved brewing process in which the double enzyme liquid composed of lipase and acid protease is directly added to the cellar, and the control of the addition position of the double enzyme liquid is the main part, and further combined with the optimization and control of the brewing conditions such as the composition of the double enzyme liquid, the distillation speed, the saccharifying power of the large-koji, the temperature and moisture content of the grain mash entering the cellar, so that the ethyl hexanoate content of the produced raw liquor is greatly increased, and the product quality of the strong-flavor liquor brewed in the large cellar is improved. The improved brewing process is easy to develop the control program of the intelligent brewing process, and promotes the application and development of intelligent brewing. BRIEF DESCRIPTION OF DRAWINGS

[0020] Fig. 1 , (a) the chromatogram detection spectrum of the raw liquor sample obtained by adding the double enzyme liquid to the lower part of the cellar in the test group and (b) the chromatogram detection data.

[0021] Fig. 2 , (a) the chromatogram detection spectrum of the raw liquor sample obtained by adding the double enzyme liquid to the upper part of the cellar in the test group and (b) the chromatogram detection data.

[0022] Fig. 3 , (a) the chromatogram detection spectrum of the raw liquor sample obtained by adding the double enzyme liquid to the middle part of the cellar in the test group and (b) the chromatogram detection data. DETAILED DESCRIPTION

[0023] The technical solutions of the present application will be described clearly and completely below in combination with the embodiments. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0024] The test methods in the following examples and comparative examples are all the conventional methods, unless otherwise specified. The raw materials or test materials used are all the typical products purchased in the market, unless otherwise specified. The quantitative tests in the following examples and comparative examples are all set up with three repeated tests, and the results are averaged.

[0025] Example

[0026] The fermentation and brewing process of the northern strong-flavor liquor is centered on "continuing to add daqu, mixing and steaming, and mud pit fermentation", and the process flow is usually "fermentation end → out of pit mixing → distillation of liquor and grain → spreading and airing of starter → into pit fermentation → fermentation end" to form a cycle. The out of pit mixing refers to mixing the fermented fermented grains and grains uniformly and then loading into the retort; the distillation of liquor and grain refers to distilling the loaded grains and grains, aiming to extract the alcohol, flavor substances and aroma of the grains; the spreading and airing of starter refers to adding daqu to the distilled grains after adding slurry (for adjusting the moisture content of the grains, also known as adjusting the water content) and cooling (usually through a cooling machine) to a suitable temperature, and then putting into the pit; the into pit fermentation refers to adding all the raw materials into the pit for the next round of fermentation. Daqu contains microorganisms such as molds, yeasts and bacteria, and enzyme liquid, which constitute the "saccharification and fermentation agent" for liquor brewing, can convert the starch in grains into fermentable sugar (saccharification), and then convert the sugar into alcohol (fermentation); and is also an important source of liquor flavor substances.

[0027] In the fermentation and brewing process, the brewing conditions have an important influence on the quality of the base liquor. Among the many brewing conditions, the present application controls the distillation speed in the distillation of liquor and grain process, the moisture content of grains, the temperature of grains into pit, the saccharifying power of daqu used, the composition of enzyme liquid added in the into pit fermentation process, and the position of enzyme liquid added into the pit as the optimization conditions of the brewing process, so as to improve the content of ethyl hexanoate in the northern strong-flavor liquor.

[0028] (1) Test the influence of different daqu saccharifying power on improving the content of ethyl hexanoate in base liquor Brewing conditions: control the distillation speed of the wine distillation process at about 3.5 kg / min; control the moisture content of the fermented grains at 58% and the temperature of the fermented grains entering the pit at 24℃; add a mixed enzyme solution with a mass ratio of lipase to acid protease of 1:30 to the upper part of the pit (i.e. more than 3 / 5 of the pit height) after the mixed enzyme solution is prepared; the other operation steps and conditions of the above-mentioned processes, as well as the operation steps and conditions of other processes of the brewing process, are carried out according to the current brewing process requirements (for specific operations and term analysis, refer to GB / T 15109-2021 Liquor Industry Terms); the effects of different diastatic powers of Daqu on the quality of raw liquor are tested, and other conditions remain unchanged in the single-factor test.

[0029] Test 1: diastatic power 342 U / g, test 2: diastatic power 457 U / g, test 3: diastatic power 556 U / g, test 4: diastatic power 676 U / g, test 5: diastatic power 725 U / g, test 6: diastatic power 885 U / g, test 7: diastatic power 945 U / g, test 8: diastatic power 1088 U / g; the diastatic power of Daqu is tested according to QB / T4257-2011 General Analysis Method for Liquor Daqu.

[0030] The content of ethyl hexanoate in raw liquor is tested according to GB / T10345-2022 Analysis Method for Liquor, and the results of each test group are shown in Table 1.

[0031] Table 1 Effects of diastatic power of Daqu on content of ethyl hexanoate

[0032] As can be seen from the data in Table 1, when the diastatic power of Daqu is between 700 and 900 U / g, it has a significant effect on the increase of ethyl hexanoate content. When it is lower than 700 or higher than 900, it has no obvious effect on the generation of ethyl hexanoate. If the diastatic power is too low, it will cause ethanol fermentation to be slow and the reproduction of miscellaneous bacteria to be enhanced, which will affect the generation of ethanol and the generation of precursor substances for ethyl hexanoate, thereby affecting the esterification of fragrant substances in the later period and causing the content of ethyl hexanoate to decrease. If the diastatic power is too high, the saccharification will be fast in the early stage of fermentation, and there will be too much accumulation of oligosaccharides and reducing sugars. Under the premise of equivalent fermentation power, acetic acid bacteria and other miscellaneous bacteria will utilize the sugars for other fermentation, which will also cause the decrease of ethanol generation and indirectly affect the generation of ethyl hexanoate.

[0033] (II) Effects of different ratios of lipase and acid protease in the test on the content of ethyl hexanoate Brewing conditions: control the distillation speed of wine and grain in the wine distillation process at about 3.5 kg / min; control the moisture content of the fermented grains at 58% in the spreading and airing of the starter process, control the temperature of the fermented grains into the pit at 24℃, and select the high-amylolytic power 457 U / g of Daqu; add the mixed enzyme solution of lipase and acid protease to the upper part of the pit (i.e. more than 3 / 5 of the height of the pit) in the pit fermentation process, and other brewing operations and conditions (including other operations and conditions of the above processes, other process operations and conditions) are carried out according to the current brewing process requirements and remain unchanged, and the effects of different dosages of lipase and acid protease on the quality of raw wine are tested by single factor test.

[0034] The mass ratio of lipase and acid protease: test 1-1:20, test 2-1:30, test 3-1:40, test 4-1:50, and the results are shown in Table 2.

[0035] Table 2 Effects of the dosage ratio of lipase and acid protease on the content of ethyl hexanoate

[0036] As can be seen from the data in Table 2, the dosage ratio of lipase and acid protease 1:40 can significantly increase the content of ethyl hexanoate in raw wine.

[0037] (Three) Effects of adding the double enzyme solution to different positions of the pit on the content of ethyl hexanoate Brewing conditions: control the distillation speed of wine and grain in the wine distillation process at about 3.5 kg / min; control the moisture content of the fermented grains at 58% in the spreading and airing of the starter process, control the temperature of the fermented grains into the pit at 24℃, and select the high-amylolytic power 457 U / g of Daqu; add the mixed enzyme solution of lipase and acid protease to the upper part of the pit (i.e. more than 3 / 5 of the height of the pit) in the pit fermentation process, and other brewing operations and conditions (including other operations and conditions of the above processes, other process operations and conditions) are carried out according to the current brewing process requirements and remain unchanged, and the effects of adding the mixed enzyme solution to different positions of the pit on the quality of raw wine are tested by single factor test.

[0038] The addition position of the double enzyme solution: test 1 upper part of the pit (i.e. more than 3 / 5 of the height of the pit), test 2 middle part of the pit (between the upper part and the lower part), test 3 lower part of the pit (i.e. less than 1 / 4 of the height of the pit); the results are shown in Table 3 below, and the chromatographic detection spectrum and detection data of the raw wine samples obtained in different test groups are shown in Figs. 1-3

[0039] Table 3 Effects of the addition position of the enzyme solution on the content of ethyl hexanoate

[0040] As can be seen from the data in Table 3, adding the double enzyme solution to the lower part of the pit can significantly increase the content of ethyl hexanoate in raw wine. ​

[0041] The fermentation process of Baijiu produces ethanol in the early stage, produces acid in the middle stage, and esterification and aroma generation in the late stage. The production of ethanol in the early stage leads to the formation of yellow water in the upper half of the pit, which is enriched in the lower part of the pit. The soaking of yellow water causes the pit mud to be in an anaerobic environment, and the Clostridium in the pit mud proliferates anaerobically to produce a large amount of caproic acid. The caproic acid migrates into the fermented grains with yellow water and esterifies with ethanol to generate aroma. The inventors have found through a large number of experiments that enzymes require a large amount of precursors, caproic acid, ethanol and moisture, in the esterification process. The bottom of the pit is the area with the largest contact area between fermented grains and pit mud, and is also the location where yellow water accumulates. The part soaked by yellow water is in full contact with pit mud, which causes a large amount of caproic acid produced in the pit mud to be incorporated into yellow water, thereby increasing the contact between caproic acid and double enzymes, and providing sufficient ethanol and moisture for the esterification of double enzymes. Therefore, by controlling the direct addition of double enzyme liquid to the lower part of the pit, the generation amount of caproic acid ethyl ester can be significantly improved.

[0042] (Four) Effect of different water content of grain mash on the content of caproic acid ethyl ester Brewing conditions: The distillation speed of the upper steaming and distillation of grains is controlled at about 3.5 kg / min, the temperature of grain mash entering the pit in the spreading and airing of starter is controlled at 24℃, and the starter with a saccharifying power of 457 U / g is selected; the mixed enzyme liquid with a mass ratio of lipase to acid protease of 1:30 is added to the pit, and is controlled to be added to the upper part of the pit (i.e. more than 3 / 5 of the height of the pit), and other brewing operations and conditions (including other operations and conditions of the above-mentioned procedures, and other procedure operations and conditions of the process flow) are carried out and kept unchanged according to the current brewing process requirements, to carry out the single factor test of the effect of different water content of grain mash on the brewing quality of raw wine.

[0043] Water content of grain mash: test 1-53%, test 2-54%, test 3-55%, test 4-56%, test 5-57%, test 6-58%, and the results are shown in Table 4.

[0044] Table 4 Effect of water content of grain mash on the generation amount of caproic acid ethyl ester

[0045] As shown by the data in Table 4, the control of the water content of grain mash at 56-57% can significantly improve the content of caproic acid ethyl ester in raw wine, and when the water content is less than 54%, the pit mud is easy to be compacted, and the Clostridium will die in large quantities, resulting in a decrease in the generation amount of caproic acid, which will ultimately affect the generation of caproic acid ethyl ester.

[0046] It is found through a large number of experiments that the water content of grain mash plays an important role in the generation of caproic acid ethyl ester: small water content causes rapid fermentation temperature rise, which produces excessive acetic acid bacteria, corresponding alcohol fermentation is hindered, and the content of ethanol, a prerequisite for the formation of caproic acid ethyl ester, is reduced; in addition, small water content also affects the anaerobic environment of pit mud, especially the activity of Clostridium in the lower half of the pit mud, which causes a decrease in the generation content of caproic acid.

[0047] (V) Test the impact of different distillation speed on ethyl hexanoate content Brewing conditions: the moisture content of the spread and aired starter is controlled at 58%, the starter is added to the pit at 24℃, and the saccharifying power of the Daqu is 457 U / g; the mixed enzyme solution with a mass ratio of 1:30 of lipase and acid protease is added to the upper part of the pit (i.e. more than 3 / 5 of the pit height), and other brewing operations and conditions (including other operations and conditions of the above-mentioned process and other process operations and conditions) are carried out and kept unchanged according to the current brewing process requirements, and the single-factor test of the impact of different distillation speed on the quality of base liquor brewing is carried out.

[0048] Distillation speed: test 1-2.0 kg / min, test 2-2.5 kg / min, test 3-3.0 kg / min, test 4-3.5 kg / min, and the results are shown in Table 5.

[0049] Table 5 Impact of distillation speed on ethyl hexanoate content

[0050] As can be seen from the data in Table 5, the distillation speed controlled below 2.5 kg / min can significantly increase the content of ethyl hexanoate in base liquor.

[0051] During the distillation process, steam passes through the wine lees (equivalent to the function of the tray), carrying alcohol, ethyl hexanoate and other substances into the condenser to condense into liquid. Through continuous evaporation, condensation and enrichment, the content is continuously increased. The control of distillation speed is mainly through the vapor pressure. The smaller the vapor pressure, the slower the distillation speed, and vice versa. Through a large number of tests, it is found that if the vapor pressure is large, the condensation and evaporation process time is shortened, the enrichment amount of ethyl hexanoate is reduced, resulting in less content of ethyl hexanoate in the final extracted liquor. On the contrary, the content of ethyl hexanoate in the liquor is more. However, when the distillation speed is lower than 2.0 kg / min, the production efficiency is reduced. Therefore, the distillation speed is not the lower the better, and the balance between efficiency and quality needs to be considered. The distillation speed between 2.0-2.5 kg / min has good product quality and high production efficiency.

[0052] (VI) Test the impact of different starter pit temperature on ethyl hexanoate content Brewing conditions: control the distillation speed of about 3.5 kg / min in the process of steaming liquor and grains; control the moisture content of 58% in the process of spreading and airing starter; select the Daqu with saccharifying power of 457 U / g; in the process of fermentation into pit, add the mixed enzyme liquid with the mass ratio of lipase and acid protease of 1:30 into the upper part of pit (i.e. more than 3 / 5 of the height of pit), and other brewing operations and conditions (including other operations and conditions of the above process and other process operations and conditions) are carried out and kept unchanged according to the current brewing process requirements, and the single factor test of the effect of different fermentation temperature of grains into pit on the brewing quality of raw liquor is carried out.

[0053] Grains into pit temperature: test 1-15℃, test 2-16℃, test 3-17℃, test 4-18℃, test 5-19℃, test 6-20℃, test 7-21℃, test 8-22℃, test 9-23℃, test 10-24℃, and the results are shown in Table 6.

[0054] Table 6 Effect of grains into pit temperature on ethyl hexanoate content

[0055] From the data in Table 6, it can be seen that the control of grains into pit temperature at 18-22℃ can significantly increase the content of ethyl hexanoate in raw liquor.

[0056] It is found through a large number of tests that the control of grains into pit temperature is closely related to the control of moisture, and moisture is the regulator of temperature, and the temperature into pit is the prerequisite for controlling the temperature in the later period, and too high or too low temperature is not conducive to the generation of ethyl hexanoate. When the temperature is too high and exceeds 22℃, the temperature rises rapidly in the early stage, which also causes a large number of acetic acid bacteria; on the contrary, the ethanol fermentation is hindered. When the temperature is too low and is lower than 18℃, the fermentation is slow, which leads to the rapid downward leaching of the upper moisture, the yeast does not undergo the aerobic reproduction in the early stage, which causes the lack of anaerobic fermentation power in the later stage, and the production of ethanol is significantly reduced.

[0057] (Seven) Orthogonal test of the above six factors 1. Test scheme According to the above single factor test, two levels of each factor are selected for orthogonal test design according to the main influence of six factors, and L8(2 7 (7 factors and 2 levels, a total of 8 treatment tests, and the 7th factor is empty column) orthogonal test scheme, the test factor level is shown in Table 7, and the orthogonal test scheme is shown in Table 8.

[0058] Table 7 Test factor level table for affecting the generation of ethyl hexanoate

[0059] Table 8 Orthogonal test scheme L8(2 7 ) for affecting the generation of ethyl hexanoate

[0060] 2. Test results Table 9 Orthogonal test results affecting ethyl caproate production

[0061] By range analysis of each treatment, the order of the six factors affecting ethyl caproate production from high to low is as follows: enzyme liquid addition position > enzyme liquid ratio > distillation speed > Daqu saccharifying power > fermented grains temperature > empty column (test error) > fermented grains moisture content.

[0062] The range of fermented grains moisture content 0.005 is less than the empty column 0.20 (test error), indicating that the fermented grains moisture content of 56% and 57% has no difference in the production of ethyl caproate.

[0063] Based on the above results, the optimal combination of the six factors is as follows: Daqu saccharifying power 725 U / g, lipase and acid protease dosage ratio 1:40, double enzyme liquid addition position at the bottom of the pit, distillation speed 2.0~2.5 kg / min, fermented grains moisture content 56~57%, and fermented grains temperature 18~20℃.

[0064] (Eight) Verification of the influence of each optimal condition on the increase of ethyl caproate content in base liquor Test sample: Daqu saccharifying power 725 U / g, lipase and acid protease ratio 1:40, added to the bottom of the pit, fermented grains moisture content 56%, distillation speed 2.0~2.5 kg / min, and fermented grains temperature 19℃. There are 10 test pits.

[0065] Control sample: Daqu saccharifying power 457 U / g, lipase and acid protease ratio 1:30, added to the top of the pit, fermented grains moisture content 58%, distillation speed controlled at 3.5 kg / min, and fermented grains temperature controlled at 24℃ (the brewing conditions of the control sample are the brewing process conditions before optimization). There are 2 control pits, and the results are shown in Table 10.

[0066] Table 10 Verification test of optimal conditions

[0067] As can be seen from the data in Table 10, it is determined that under the process conditions of Daqu saccharifying power 700~800 U / g, lipase and acid protease dosage ratio 1:40, enzyme liquid addition position at the bottom of the pit (total pit depth 3 meters, bottom at 1 / 4 of the pit), fermented grains moisture content 56%~57%, distillation speed 2.0~2.5 kg / min, and fermented grains temperature 18~20℃, the ethyl caproate content of base liquor can be increased by more than 30%.

[0068] In summary, the present application is directed to the problem of the few ethyl hexanoate content in base liquor and the uncoordinated taste of pit-fermented Luzhou-flavor liquor, and proposes an improved brewing process of directly adding lipase and acid protease double enzyme liquid into the pit during the pit-fermentation process and controlling the adding position of the double enzyme liquid, and then optimizing the composition of the double enzyme liquid, the distillation speed, the saccharifying power of Daqu, the temperature and moisture content of the fermented grains, and other brewing conditions, so as to significantly increase the ethyl hexanoate content in base liquor, improve the product quality of pit-fermented Luzhou-flavor liquor, and maintain the rich style characteristics of typical northern Luzhou-flavor liquor without changing the brewing process and increasing the production cost. The improved brewing process of Luzhou-flavor liquor is conducive to the development of intelligent brewing process control program and related products, and has a positive promoting effect on the intelligent development and application of the liquor brewing industry.

[0069] Please note that the technical features of the above embodiments can be combined arbitrarily, and in order to make the description simple, all possible combinations of the technical features in the above embodiments are not described, however, as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present application. The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the scope of the present application. Therefore, the patent protection scope of the present application should be subject to the appended claims.

Claims

1. A brewing method for increasing the content of ethyl hexanoate in northern strong-flavor Chinese liquor, characterized by comprising the following steps: In the large-pit brewing process of the northern Luzhou-flavor liquor, a double-enzyme liquor obtained by mixing a lipase and an acid protease is added to the pit in the pool-adding fermentation process, the double-enzyme liquor is controlled to be added to a position at a distance of not more than one fourth of the pit height from the pit bottom, and the ethyl hexanoate content of the base liquor is increased. ​ 2. The brewing method for increasing the content of ethyl hexanoate in Baijiu (liquor) with northern style according to claim 1, characterized in that: The mass ratio of the lipase to the acid protease in the double-enzyme liquor is 1:30-40, and is further preferably 1:

40.

3. The brewing method for increasing the content of ethyl hexanoate in Baijiu (liquor) according to claim 1, characterized in that: In the distillation-grain process of the upper-distillation liquor distillation in the large-pit brewing process, the distillation speed is controlled to be not more than 2.5 kg / min, and is further preferably 2.0-2.5 kg / min.

4. The brewing method for increasing the content of ethyl hexanoate in Baijiu (liquor) according to claim 1, characterized in that: In the spreading and airing of the starter in the large-pit brewing process, the daqu with a saccharifying power of 700-900 U / g is added, and the daqu saccharifying power is further preferably 700-800 U / g.

5. The brewing method for increasing the content of ethyl hexanoate in Baijiu (liquor) according to claim 1, characterized in that: In the spreading and airing of the starter in the large-pit brewing process, the temperature of the fermented grains entering the pit is controlled to be 18-22 ℃, and the temperature of the fermented grains entering the pit is further preferably 18-20 ℃.

6. The brewing method for increasing the content of ethyl hexanoate in Baijiu (liquor) according to claim 1, characterized in that: In the spreading and airing of the starter in the large-pit brewing process, the moisture content of the fermented grains is controlled to be 56-57%.

7. The brewing method for increasing the content of ethyl hexanoate in Baijiu (liquor) according to claim 1, characterized in that: The ethyl hexanoate content of the base liquor is not less than 1.6 g / L.

8. The brewing method for increasing the content of ethyl hexanoate in Baijiu (liquor) according to any one of claims 1-7, characterized in that: The large-pit has a capacity of more than 20 cubic meters.

9. The application of the brewing method for increasing the content of ethyl hexanoate in Baijiu (liquor) of the Northern style as claimed in any one of claims 1-8 in intelligent brewing, characterized in that: The brewing method is used for the development and application of the control program of the intelligent brewing process.

10. A computer-readable storage medium, characterized in that: The computer program product comprises one or more program instructions, which, when running on the computer, enable the computer to execute the brewing method according to any one of claims 1-8.

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