A method for distilling Maotai-flavor liquor and application thereof

Abstract

This application relates to a method for steaming a type of soy sauce-flavored baijiu and its application. The initial bottom-laying stage includes: after preheating the still with steam, spreading the mash to be steamed on the still grate to form 1-3 layers, each layer with a thickness of 3-4 cm, and controlling the steam pressure at 0.045-0.055 MPa. The middle stage of main distillation includes: continuing to spread the mash to be steamed, with 4-17 layers, each layer with a thickness of 2-4 cm, maintaining the steam pressure at 0.045-0.055 MPa, and controlling the steaming speed to be synchronized with the steam exit speed. The total duration of this stage is controlled at 35-40 minutes. The final sealing stage includes: when the material layer reaches 80% of the height of the still, reducing the steam pressure to ≤0.02 MPa, each layer with a thickness of 1-2 cm, loosening the mash to be steamed, and then steaming it to the mouth of the still. This method, through three-stage standardized parameter control combined with final loosening treatment technology, can effectively increase the yield and average alcohol content of base liquor, increase the content of key aroma substances, significantly improve operational consistency, and reduce production fluctuations.

Description

Technical Field

[0001] This application belongs to the field of liquor brewing technology, and in particular relates to a method for steaming sauce-flavored liquor and its application. Background Technology

[0002] As an important representative of Chinese baijiu aroma, Maotai-flavor baijiu has a complex and unique production process, characterized by "high-temperature koji making, high-temperature stacking, high-temperature fermentation, multiple distillations, and multiple extractions." The stilling process, a crucial step in the "nine distillations" of Maotai-flavor baijiu, plays a decisive role in the yield of base liquor, alcohol content, and the enrichment of aroma components. Traditional Maotai-flavor baijiu producers are mostly located in the core production area of ​​the Chishui River basin. Influenced by geographical environment and the inheritance of traditional techniques, the stilling operation has long relied mainly on manual experience.

[0003] In existing technologies, traditional manual steaming follows the six-word principle of "light, loose, even, thin, accurate, and level." Operators rely on their accumulated personal experience, subjectively judging and controlling the steaming speed, layer thickness, and steam pressure through visual inspection and touch to achieve distillation and separation of the mash. This experience-based operating mode has accumulated certain technical expertise over long-term production practice. However, existing technologies have the following limitations: First, there is a lack of operational consistency. Due to the lack of quantitative standards, there are significant differences in operation between different work groups and different operators, resulting in a fluctuation range of 10%-15% in the quality of the base liquor.

[0004] Second, human error is difficult to control. Traditional methods lack precise quantitative standards for controlling key parameters such as steam pressure and bed thickness, which can easily lead to "steam pressure" (insufficient steam penetration) or "steam escape" (steam dissipation). In traditional steam distillation processes, the incidence of "steam pressure" can reach 18%, and the incidence of "steam escape" can reach 12%, directly affecting distillation efficiency.

[0005] Third, the problem of compaction in the final stage of fermentation is prominent. When the fermentation layer reaches more than 80% of the height of the still, the increased pressure due to the weight of the mash, coupled with limited operating space, easily leads to compaction, resulting in insufficient extraction of residual alcohol and aroma substances from the mash. Traditional methods achieve an alcohol extraction rate of only 82.3% and an aroma substance extraction rate of less than 80% in the final stage.

[0006] Fourth, it relies too heavily on the experience of operators. A qualified steamer operator typically needs a training period of 6-9 months to operate independently, and their skill levels vary greatly. This high dependence restricts the stability of large-scale production.

[0007] Therefore, a new technical solution is needed to reduce human error and improve operational consistency by establishing a standardized operating parameter system, especially to solve the technical problem of insufficient extraction of the final material layer, so as to improve the stability of base liquor yield and quality. Summary of the Invention

[0008] The purpose of this application is to provide a method for steaming sauce-flavored baijiu and its application, in order to solve the technical problems in the existing traditional steaming process, such as insufficient standardization of operation, difficulty in controlling human error, low extraction efficiency of the final material layer, and excessive reliance on the experience of operators.

[0009] This application provides a method for steaming a type of soy sauce-flavored baijiu, comprising a preliminary bottom-laying stage, a middle stage of main distillation, and a final sealing stage, performed sequentially. The preliminary bottom-laying stage includes: preheating the still with steam, then spreading 1-3 layers of mash to be steamed onto the still grate, each layer controlled to a thickness of 3-4 cm, and controlling the steam pressure at 0.045-0.055 MPa. The middle stage of main distillation includes: continuing the steaming process on the foundation of the mash layer formed in the preliminary bottom-laying stage. Spread the mash to be added, with 4-17 layers, each layer controlled at 2-4cm thickness, maintaining a steam pressure of 0.045-0.055MPa, and controlling the feeding speed to be synchronized with the steam exit speed. The total duration of this stage is controlled at 35-40 minutes. The final sealing stage includes: when the material layer reaches 80% of the height of the still, reducing the steam pressure to ≤0.02MPa, controlling the thickness of each layer at 1-2cm, loosening the mash to be added, and then feeding it to the mouth of the still.

[0010] A preferred approach is that, during the initial bottom-laying stage, the specific parameters for steam preheating are as follows: open the steam valve to preheat the still for 5 minutes, control the steam pressure at 0.08-0.10 MPa, and after preheating, turn off the steam before spreading the mash.

[0011] A preferred approach is to use a detection tool to check the porosity of the material layer after every two layers of material are laid during the main distillation stage in the middle section.

[0012] A preferred embodiment is that the detection tool is a metal probe with a diameter of 1 cm and a length of 50 cm.

[0013] A preferred approach is to use a loosening tool to loosen and remove the mash during the final capping stage, and then place the loosened mash in a lifting container for use by the steaming personnel.

[0014] A preferred approach is to control the volume of the fermented mash in the lifting container after emptying it to less than two-thirds of the container's capacity.

[0015] A preferred approach is that the initial stage of laying the base also includes: before spreading the mash to be added, pouring the reserved tail liquor into the earthen pot.

[0016] A preferred approach is that the steaming operation in the main distillation stage of the middle section follows the principle of "steam pressure upon steam exposure," that is, the steaming speed is adjusted according to the steam outflow speed so that the steam just penetrates the newly laid material layer.

[0017] A preferred approach is that the steaming operation in the final capping stage follows the principle of steam pressure reduction, and the steaming speed decreases synchronously with the decrease in steam pressure.

[0018] This application also provides the application of the steaming method for the sauce-flavored baijiu in the production of baijiu base liquor. Beneficial effects

[0019] (1) By establishing a standardized parameter system through the three-stage steaming operation method, the consistency of operation is significantly improved, the fluctuation of steaming speed is reduced, and the uniformity of material layer is improved. This effectively solves the problems of insufficient standardization of traditional technical operation and significant differences between different shifts and operators. (2) By precisely controlling the steam pressure and material layer thickness at each stage, and especially by innovatively introducing a technique to loosen the mash in the final stage, the porosity of the material layer is significantly improved, the steam penetration efficiency is increased, the alcohol extraction rate in the final stage is increased, and the base liquor yield is increased. This effectively solves the technical problem of low extraction efficiency caused by compaction of the material layer in the final stage. The porosity of the material layer is increased from about 35% in the traditional method to more than 48%, the steam penetration efficiency is increased by 37%, and the extraction rate of residual alcohol in the mash (from 82.3% to 86.7%) and the extraction efficiency of aroma substances are significantly improved. (3) The average alcohol content of the base liquor is increased, the alcohol stability is improved, the content of key aroma substances is significantly increased, the rate of high-quality products is improved, the fluctuation range of base liquor quality is reduced, and the product quality stability is significantly improved. (4) By establishing standardized operating procedures and quality control indicator system, the reliance on operator experience was reduced. The method showed good applicability and stability in different rounds, especially in the core three rounds, which proved the replicability and promotion value of the method. Detailed Implementation

[0020] The technical solutions of this application are further illustrated below through specific embodiments. These specific embodiments do not represent a limitation on the scope of protection of this application. Any non-essential modifications and adjustments made by others based on the concept of this application still fall within the scope of protection of this application.

[0021] This embodiment provides a method for feeding soy sauce-flavored baijiu into the still, including an initial bottom-laying stage, a middle main distillation stage, and a final capping stage performed in sequence: The initial bottom-laying stage includes: after preheating the still with steam, spreading 1-3 layers of mash to be fed onto the still grate to form a base layer, with each layer controlled to a thickness of 3-4 cm, and controlling the steam pressure to be 0.045-0.055 MPa; The middle main distillation stage includes: continuing to spread mash to be fed on the base layer formed in the initial bottom-laying stage. The material layering process involves 4-17 layers, with each layer controlled at a thickness of 2-4cm. The steam pressure is maintained at 0.045-0.055MPa, and the feeding speed and steam exit speed are synchronized. The total duration of this stage is controlled at 35-40 minutes. The final sealing stage includes: when the material layer reaches 80% of the height of the still, the steam pressure is reduced to ≤0.02MPa, and the mash to be fed is continued to be spread to the mouth of the still. Each layer is controlled at a thickness of 1-2cm. After loosening the mash, it is fed to the mouth of the still.

[0022] In this embodiment, a three-stage steaming operation method is adopted, clearly dividing the traditional steaming process into three stages with different technical requirements: initial, middle, and final. By standardizing the steaming operation process, a standardized operating parameter system is established for controlling key parameters such as material layer thickness and steam pressure at each stage, avoiding "steam compression" or "steam leakage" caused by human judgment errors. Simultaneously, the key technical step of "final stage material removal" is incorporated, which introduces a technique to loosen the mash to be steamed at the final stage. This significantly increases the porosity of the material layer, improves steam penetration efficiency, increases the final stage alcohol extraction rate, and increases the base liquor yield, effectively solving the technical problem of low extraction efficiency caused by material layer compaction at the final stage. It should be noted that "final stage material removal" refers to one person using a rake to scoop the mash to be steamed into a scoop during the steaming process, and then the steaming personnel evenly spread the mash from the scoop into the steamer.

[0023] The above-mentioned phased standardized parameter control scheme achieves controllability and repeatability of the steaming process, significantly reduces human error, improves consistency of operation between different shifts and different steaming times, changes the traditional fuzzy control mode that relies on personal experience, and makes the operation process have clear technical standards and quantifiable quality control points, shortens the training cycle, and improves the replicability and promotion of the technology.

[0024] Each step is explained in detail below.

[0025] S1. The initial bottom-laying stage includes: after preheating the still with steam, spreading the mash to be added on the still grate to form 1-3 layers, each layer with a thickness of 3-4cm, and controlling the steam pressure to 0.045~0.055MPa; In this embodiment, it should be noted that the initial stage is the bottom-laying stage, which consists of layers 1-3. This stage is crucial for establishing a good foundation for distillation. Specific operational requirements are as follows: First, open the steam valve to preheat the steamer for at least 5 minutes. The steam pressure should be strictly controlled between 0.08-0.10 MPa, such as 0.08 MPa, 0.085 MPa, 0.09 MPa, or 0.10 MPa. The purpose of preheating is to ensure a uniform temperature increase on the inner wall of the steamer, preventing localized condensation due to temperature differences when adding more steam later. The selection of a preheating steam pressure of 0.08-0.10 MPa is based on the following considerations: if the pressure is too low (below 0.08 MPa), the steam flow rate will be insufficient, requiring a preheating time of more than 8 minutes, resulting in unsatisfactory preheating effects; if the pressure is too high (above 0.10 MPa), steam consumption will increase by approximately 30%, leading to energy waste and failing to significantly shorten the preheating time.

[0026] After preheating, turn off the steam before spreading the mash. Take the fermented mash ready to be added and spread it evenly on the still grate using a light spreading and pressing method, forming 1-3 layers. The thickness of each layer should be controlled at 3-4cm, for example, 3cm, 3.5cm, and 4cm. This allows for uniform steam penetration and ensures that the material layer reaches the ideal state of "loose and uniform, with moderate porosity". The purpose of the bottom layer is to form a loose layer of mash at the bottom of the still, preventing the alcohol molecules and aroma substances in the tail liquor poured into the still from evaporating, while providing a uniform channel for subsequent steam penetration. The selection of the total thickness of the bottom layer in the range of 3-12cm is based on the following: if the thickness is too thin (less than 3cm), it cannot effectively prevent the evaporation of tail liquor, and the alcohol loss rate increases by about 2%; if the thickness is too thick (more than 12cm), the weight of the material layer increases, the bottom mash is compacted, and the porosity decreases from the ideal 50% to below 35%, affecting the uniformity of steam penetration.

[0027] After the base layer is laid, the reserved tail liquor is poured into the still, with a quantity of 8-10 kg per still, and an alcohol content of approximately 20-25% vol. Then, the steam valve is opened, and the steam pressure is adjusted and controlled to 0.045-0.055 MPa, for example, 0.045 MPa, 0.046 MPa, 0.047 MPa, 0.049 MPa, 0.050 MPa, 0.052 MPa, and 0.055 MPa. A distillation steam pressure of 0.045-0.055 MPa is the optimal control range for the still distillation of Maotai-flavor baijiu, ensuring uniform steam penetration while achieving efficient extraction of alcohol and aroma compounds. When the pressure is below 0.045 MPa, the steam penetration is insufficient, the distillation time is extended by about 30%, and the alcohol extraction rate in the final stage is reduced to below 80%. When the pressure is above 0.055 MPa, the steam flow rate is too fast, which easily causes the steam to overflow, the material layer is dispersed by the steam, the uniformity decreases, and the aroma substances escape rapidly with the steam, reducing the extraction selectivity.

[0028] After the bottom of the steamer is laid out and the pot is brought to a boil, observe that the steam is evenly emitted from the steamer grate without any local steam escaping or no steam escaping. This indicates that the initial operation is complete and the next stage can begin.

[0029] S2. The main distillation stage in the middle section includes: on the material layer formed in the initial stage, the mash to be added is spread again. The number of material layers is 4-17, and the thickness of each layer is controlled at 2-4cm. The steam pressure is maintained at 0.045-0.055MPa, and the feeding speed and the steam exit speed are controlled to be synchronized. The total duration of this stage is controlled at 35-40 minutes. In this embodiment, it should be noted that the middle section is the main distillation stage, which includes layers 4-17. This stage is the main period for the extraction of alcohol and main aroma substances, and the operation requires more precise techniques. The specific process is as follows: Keep the steam pressure stable within the range of 0.045-0.055MPa, and continue to spread the mash to be added on the basis of the material layer formed in the initial stage. The feeding speed should follow the steam penetration speed to achieve steam pressure mash, that is, immediately spread the next layer of mash after observing the steam penetrating from the surface of the material layer.

[0030] The material is layered 4-17 times during the steaming process, with each layer controlled at a thickness of 2-4 cm, such as 2 cm, 2.5 cm, 3 cm, 3.5 cm, and 4 cm. After each layer is laid, it is gently patted flat with a wooden rake to ensure that the thickness error of each layer does not exceed ±0.5 cm. The key technical point at this stage is to maintain a uniform steaming speed to ensure efficient extraction of alcohol and the main aroma substances, while avoiding a decrease in distillation efficiency due to improper operation. The material layer thickness is controlled at 2-4 cm per layer. This thickness range is selected based on the principle of "thin" in the process requirements of "light, loose, uniform, thin, accurate, and flat," that is, the covering should be thin to ensure uniform steam penetration.

[0031] During the intermediate stage of operation, a specially designed metal probe is used to test the porosity of the material layer after every two layers are laid. The metal probe is 1 cm in diameter and 50 cm long. Uniform resistance and smooth insertion of the probe into the material layer indicate good porosity. If the insertion resistance is too high or the probe cannot be inserted in some areas, the material layer needs to be further loosened. The purpose of testing the porosity of the material layer is to promptly identify and correct any compaction problems, ensuring unobstructed steam penetration channels. Preferably, the insertion resistance should be ≤5N.

[0032] The total duration of the middle section should be strictly controlled within the range of 35-40 minutes. Considering that the final stage, which requires 5-10 minutes for capping, is also necessary, the middle section duration should ideally be controlled within the range of 35-40 minutes. If the duration is too short (below 35 minutes), the feeding speed will be too fast, making it difficult to accurately control the thickness of the mash layer and reducing uniformity; if the duration is too long (above 40 minutes), the distillation time of the mash laid in the early stage will be too long, resulting in excessive extraction of aroma substances and a decrease in the harmony of the liquor quality.

[0033] The criteria for judging the completion of the intermediate stage operation are: the material layer height reaches about 80% of the total height of the steamer, the steam penetrates evenly, and there is no obvious collapse or bulging on the surface of the material layer.

[0034] S3. The final capping stage includes: when the material layer reaches 80% of the height of the still, the steam pressure is reduced to ≤0.02MPa, and the mash to be added is spread to the mouth of the still. The thickness of each layer is controlled at 1-2cm. After the mash to be added is loosened, it is placed into the still to the mouth of the still.

[0035] In this embodiment, it should be noted that the final stage is the capping stage. The final stage begins when the material layer reaches 80% of the height of the steamer. Specific technical requirements are as follows: Reduce the steam pressure at the top of the still to the distillation steam pressure, controlling it below 0.02 MPa. The technical basis for reducing the steam pressure at the end is as follows: as the height of the mash increases, the self-weight pressure of the mash increases. If the pressure on the bottom layer increases from 0.5 kPa in the initial stage to over 2.0 kPa in the final stage, the porosity of the mash layer decreases from 50% to about 40%. If the steam pressure is maintained at 0.045-0.055 MPa, the steam will quickly escape along the path of least resistance (the edge of the mash layer), resulting in insufficient steam penetration in the center and steam leakage. After reducing the steam pressure to below 0.02 MPa, the steam flow rate slows down, the residence time inside the mash layer is extended, the penetration is more uniform, and the extraction of alcohol and aroma substances in the final stage of the mash is more complete. At the same time, the loading speed naturally decreases with the reduction of steam pressure, slowing down the operation rhythm of the still.

[0036] Meanwhile, the material layer thickness is controlled at 1-2 cm / layer, which is significantly smaller than the 2-4 cm / layer in the middle section. The reason for the reduced material layer thickness in the final stage is that the operator expends more physical strength during the final stage of steaming, and the height of the arm raised increases as it approaches the steamer opening, increasing the difficulty of operation. The purpose of reducing the material layer thickness and steaming speed is to ensure the quality of steaming in the final stage, so that the pressing operation meets the requirements of "light, loose, uniform, thin, accurate, and flat" in the process, avoiding material compaction due to improper operation.

[0037] The final stage of material removal technology is the key point of this application. During the stacking process, the mash becomes compacted due to its own weight. For example, if the density increases from 0.65 g / cm³ at the initial stacking stage to over 0.85 g / cm³, the porosity decreases from 55% to around 35%. This lack of looseness severely affects the steaming effect. During the final stage of steaming, auxiliary personnel use rakes to loosen the mash. The rakes are specialized loosening tools with teeth 8-10 cm long and 3-4 cm apart, effectively penetrating the mash pile for loosening. The auxiliary personnel use the rakes to turn the mash from the bottom of the pile upwards, making the compacted mash loose again, restoring the porosity to 45%-50%. The loosened mash is then transferred into a bamboo container with a volume of approximately 15-20 liters. The amount of material removed is controlled to be less than two-thirds of the lifting capacity, i.e., 10-13 liters each time. The basis for controlling the amount removed is: too much material makes the lifting device too heavy, making it difficult for the steaming personnel to handle, resulting in high physical exertion and making it difficult to accurately control the thickness of the material layer; too little material results in too high a removal frequency, increasing the labor intensity of auxiliary personnel and reducing collaborative efficiency. The loosened mash is then removed from the lifting device by the steaming personnel and evenly spread inside the steamer, completing the final steaming operation. The mechanism of this final removal technique is: by using external force to loosen the mash, the tightly packed state between the mash particles is broken, increasing the porosity between particles, raising the material layer porosity from 35% to over 48%, an increase of 37%. After the porosity is increased, the steam penetration resistance is significantly reduced, the steam flow within the material layer is more uniform, the contact area between the mash particles and steam increases by about 40%, improving heat and mass transfer efficiency, and resulting in more complete extraction of alcohol and aroma substances. This method significantly improved the extraction rate of residual alcohol in the mash (from 82.3% to 86.7%) and the extraction efficiency of aroma substances.

[0038] It should be noted that the still should be sealed after the final stage of operation. When sealing, a thin layer of fermented mash, approximately 0.5-1 cm thick, is spread on top of the mash layer, then the still lid is placed on top, and distillation begins. During distillation, the steam pressure is maintained at a stable 0.045-0.055 MPa, and the condensate temperature is controlled at 15-20℃. The distillation time is determined based on the height of the mash layer and the moisture content of the mash, generally 2-2.5 hours. Distillation is carried out in stages: the initial fraction with an alcohol content ≥60% vol is collected in the first-run container; the middle fraction with an alcohol content of 50-60% vol is collected in the final-run container; and the final fraction with an alcohol content <50% vol is collected in the last-run container. The criterion for stopping distillation is: the flow rate of the distillate slows significantly, and the alcohol content drops below 10% vol. At this point, the steam valve is closed, and distillation is stopped.

[0039] The method described in this application has undergone systematic experimental verification and large-scale pilot application, achieving significant technical results. Specific performance data are shown in Table 1 below: Table 1

[0040] As can be seen from the data in the table above, the application of the method in this application has brought about comprehensive technical improvements: operational stability has been significantly improved, with a 40% reduction in the fluctuation of the feeding speed; the uniformity of the material layer has been improved by 10%; the average yield of base liquor per still (1200kg of mash) has increased by 4.5 kg, an increase of 4.0%; the average alcohol content of the base liquor has increased by 2.2% vol; and the content of the key aroma substance ethyl lactate has increased by 12.1%. In addition, large-scale pilot applications show that the rate of high-quality products can be increased from 78% to 87%, the fluctuation range of base liquor quality has been reduced from 12% to 4%, and the product quality stability has been significantly improved.

[0041] The working principle of the three-stage steaming operation method combined with the final stage material removal technology used in this embodiment is as follows: The initial stage of operation establishes a uniform steam channel foundation through preheating and bottom layering. Preheating with steam pressure of 0.08-0.10 MPa raises the temperature of the inner wall of the still from the ambient temperature of 20℃ to 85-90℃, reducing the temperature gradient. This prevents localized condensation when the mash comes into contact with the still wall during subsequent loading, resulting in more uniform steam penetration. The bottom layer, 3-12 cm thick, forms a buffer layer at the bottom of the still. Alcohol molecules (boiling point 78.3℃) and aroma compounds (boiling point mostly between 150-200℃) in the tail liquor are adsorbed by the mash and slowly released and extracted with the steam, avoiding direct evaporation loss.

[0042] The steam temperature corresponding to a distillation steam pressure of 0.045-0.055 MPa is approximately 105-108℃. This temperature range is higher than the boiling point of alcohol but lower than the decomposition temperature of most aroma compounds, ensuring efficient alcohol distillation while avoiding the thermal decomposition of aroma compounds. Mid-stage operation maintains a dynamic balance of steam penetration through uniform loading speed and controlled layer thickness. The controlled steam pressure operation rhythm ensures that the surface of the layer is always in a state where steam is just beginning to emerge, resulting in high steam saturation within the layer, strong driving force for heat and mass transfer, and rapid transfer rate of alcohol and aroma compounds from the mash to the steam phase. A layer thickness of 2-4 cm per layer ensures that the internal temperature gradient of a single layer is less than 5℃, resulting in uniform heating of the mash particles and high extraction efficiency. Quality control measures, such as checking the looseness after every two layers, promptly identify compaction issues and maintain a porosity of 45%-50% by adding loose material, preventing increased steam penetration resistance.

[0043] The final stage of the process addresses the compaction issue of the mash layer by reducing steam pressure and loosening the material. After reducing the steam pressure from 0.045-0.055 MPa to below 0.02 MPa, the steam linear velocity decreases from 1.2-1.5 m / s to 0.6-0.8 m / s, extending the steam residence time within the mash layer from 8-10 seconds to 15-20 seconds, resulting in more thorough contact with the mash. The loosening process increases the porosity of the mash layer from 35% to 48%, increasing the pore volume by approximately 37% and reducing steam penetration resistance by approximately 45%. According to Darcy's law, the permeation rate is directly proportional to porosity; the increased porosity leads to a higher steam permeation rate, allowing for more complete extraction of residual alcohol (concentration approximately 3-5% vol) and aroma compounds (concentration approximately 200-300 mg / L) from the final stage of the mash.

[0044] The technical effects of this application are illustrated below using experimental examples and comparative examples.

[0045] In this article, the base liquor yield refers to the mass of base liquor obtained after distillation of each batch of mash, expressed in kg / batch.

[0046] The yield of alcohol per unit of fermented mash refers to the mass of base liquor produced per 100 kg of fermented mash, expressed in kg / 100 kg.

[0047] Production increase rate refers to the percentage increase in production relative to the control group.

[0048] Alcohol content refers to the volume fraction of ethanol in the base liquor, expressed as %vol.

[0049] Operational consistency is characterized by the fluctuation range of the steaming speed, expressed in kg / min.

[0050] The uniformity of the material layer is scored on a 10-point scale, with a higher score indicating better uniformity.

[0051] The quality indicators of the base liquor were tested according to the following method: the alcohol content was tested using a calibrated alcohol meter under standard conditions of 20℃, and three parallel samples were set up for each sample, and the average value was taken.

[0052] The content of aroma substances was determined by gas chromatography. The chromatographic conditions were as follows: DB-WAX capillary column (30m×0.25mm×0.25μm), injection port temperature 230℃, detector temperature 250℃, column temperature program 40℃ for 5 minutes, increased to 230℃ at 5℃ / min, held for 10 minutes, carrier gas was high-purity nitrogen, flow rate 1.0mL / min, split ratio 20:1, and injection volume 1.0μL.

[0053] Implementation method: System verification was carried out through multiple rounds of interchangeable comparative tests. Experiment Example 1: Verification Experiment on the Influence of Base Liquor Yield 1. Implementation content: The focus is on verifying the effect of the three-step manual steaming method (especially the final stage of material removal) on the yield of base liquor.

[0054] 2. Implementation method: A strictly controlled comparative experimental design was adopted.

[0055] 3. Comparison content: Four experimental groups were set up for systematic comparison: Experimental Group 1 (Control Group): The traditional empirical method of steaming was used throughout the process, and no material removal operation was performed at the end.

[0056] Experimental Group 2 (Three-stage steaming group): The three-stage steaming method was adopted, and no material removal operation was performed in the last stage.

[0057] Experimental Group 3 (Traditional Steaming + Material Removal): The traditional empirical method of steaming was used, and the material removal operation was carried out at the end.

[0058] Experimental Group 4 (Three-stage steaming + material removal): A three-stage steaming method was adopted, with material removal performed simultaneously at the end.

[0059] 4. Verification Standards: The main evaluation indicators are the base liquor yield (kg / still) and the liquor yield per unit of mash (kg / 100kg mash). The higher the value, the better the effect.

[0060] 5. Implementation Teams: Select two operators with similar skill levels for the steamer, designated A and B. Operator A is responsible for loading the steamer, while operator B is responsible for unloading the material at the end. This scientific grouping ensures the fairness of the experiment.

[0061] 6. Specific process: Preparation before implementation: Select mash from the same batch and with the same degree of fermentation as experimental raw materials, and strictly control the amount of mash added to each still to 1000 kg.

[0062] Environmental control: Ensure that external conditions such as steam source pressure, condensate temperature, and ambient temperature remain consistent.

[0063] Operation execution: Each experimental group strictly followed the established plan in the above embodiments and recorded detailed operation parameters.

[0064] Data collection: After distillation, the total mass of the base liquor is weighed using precise measuring equipment, and the relevant data is recorded.

[0065] 7. Implementation Data: The results obtained through system experiments are shown in Table 2 below: Table 2

[0066] Note: The reaction conditions are as follows: feed rate 1000 kg of mash, steam source pressure 0.15-0.20 MPa, condensate temperature 15-20℃, ambient temperature 18-25℃, and relative humidity 60%-70%. Statistical significance was analyzed using a t-test. P<0.05 indicated a significant difference, P<0.01 indicated a highly significant difference, and P>0.05 indicated no significant difference.

[0067] As shown in Table 2 above, the base liquor yield of experimental group 4 (three-stage steaming + unloading) was 116.2±0.35 kg / steamer, compared with 111.7±0.85 kg / steamer of experimental group 1 (control group), an average increase of 4.5 kg per steamer. The liquor yield per unit mash increased from 9.31±0.07 kg / 100 kg to 9.68±0.03 kg / 100 kg, an increase rate of 4.0%, which was statistically significant (P<0.01). The base liquor yield of experimental group 2 (three-stage steaming group) was 114.8±0.52 kg / steamer, an increase of 3.1 kg / steamer compared with the control group, an increase rate of 2.8%, which was statistically significant (P<0.05). This indicates that the three-stage steaming method itself has a positive effect on increasing yield. The base liquor yield of experimental group 3 (traditional stilling + final unloading) was 112.3 ± 0.78 kg / still, an increase of only 0.6 kg / still compared to the control group, representing a 0.5% increase. This difference was not statistically significant (P > 0.05), indicating that performing the final unloading operation alone without combining it with the three-stage operation process has no significant effect on yield improvement. The above data shows that the three-stage stilling operation method and the final unloading technology must be used in combination to produce a synergistic effect and achieve a significant increase in base liquor yield. The three-stage operation method improves overall distillation efficiency through standardized parameter control, while the final unloading technology specifically addresses the problem of final layer compaction. The two work together to ensure the most complete extraction of alcohol and aroma substances from the mash.

[0068] The experimental group (control group 1) – the traditional experience method – operated as follows: Operators, following the six-word principle of ease, accuracy, uniformity, thinness, and flatness, judged the thickness and looseness of the material layer by sight and touch, adjusted the steam valves to control the steam pressure based on experience, and judged the steaming speed by feel. No preheating was performed; steaming began directly. The initial, middle, and final stages were not clearly defined, and the steam pressure remained relatively constant throughout, approximately 0.05-0.06 MPa. The material layer thickness, depending on operator habits, was generally 3-5 cm per layer, but fluctuated significantly at different locations and times. During the final stage, the steam pressure was not reduced, and the material was not loosened by removing it; the mash was directly taken from the accumulation area and steamed. The entire process was completed independently by one operator, with steaming time approximately 40-50 minutes.

[0069] Experiment Example 2: Verification Experiment of Base Wine Quality Indicators 1. Implementation content: Systematically verify the effect of the three-step manual steaming method on the alcohol content and aroma substance content of the base liquor.

[0070] 2. Implementation method: Stratified sampling comparative test was adopted (experimental grouping is the same as in implementation one).

[0071] 3. Comparison content: The focus is on examining the average alcohol content and stability of the base liquor, as well as the changes in the content of key aroma substances (ethyl acetate, ethyl lactate, ethyl hexanoate, etc.).

[0072] 4. Verification standards: The higher the alcohol content and the smaller the fluctuation range, the better the effect; the higher the content of flavor substances and the better the coordination of each component, the better the quality.

[0073] 5. Implementation Team: The same experimental personnel configuration as Implementation Team 1.

[0074] 6. Specific process: Sampling design: Systematic sampling was conducted at different stages of the distillation process (initial alcohol content ≥60% vol, middle stage 50-60% vol, and final stage <50% vol).

[0075] Detection methods: The alcohol content was measured using a calibrated alcohol meter under standard conditions of 20°C; the content of aroma substances was detected using gas chromatography.

[0076] Quality control: All tests are conducted with parallel samples to ensure the accuracy and reliability of the data.

[0077] 7. Implementation Data: The results obtained through precise testing are shown in Table 3 below: Table 3

[0078] Note: Alcohol content was determined using an alcohol meter under standard conditions at 20℃; aroma substance content was determined using gas chromatography, with chromatographic conditions described in the main text. Three replicates were prepared for each sample, and data are presented as mean ± standard deviation.

[0079] As shown in Table 3 above, the average alcohol content of the base liquor in Experimental Group 4 (invented technology) was 57.8 ± 0.82% vol, which is 2.2% vol higher than that of Experimental Group 1 (traditional empirical method) (55.6 ± 1.23% vol), representing an increase of 4.0%. More importantly, the standard deviation of alcohol content decreased from 1.23 to 0.82, a decrease of 33.3%, indicating a significant improvement in the stability of the base liquor's alcohol content and a marked reduction in quality fluctuations between different distillations and batches. Regarding the content of aroma compounds, the content of ethyl lactate increased from 65.3±2.11 mg / 100mL to 73.2±1.51 mg / 100mL, an increase of 12.1%; the content of ethyl acetate increased from 42.5±3.2 mg / 100mL to 56.8±2.4 mg / 100mL, an increase of 33.6%; and the content of ethyl hexanoate increased from 38.6±1.5 mg / 100mL to 42.3±1.2 mg / 100mL, an increase of 9.6%. The comprehensive increase in the content of these three main esters indicates that the technology of this invention not only improves the alcohol extraction rate but also enhances the extraction efficiency of aroma compounds, resulting in a significant improvement in the aroma harmony and quality of the base liquor.

[0080] The mechanism of quality improvement is analyzed as follows: The three-stage steam distillation method achieves refined management of the distillation process through staged parameter control. Preheating with a steam pressure of 0.08-0.10 MPa in the initial stage ensures a uniform temperature field in the still, avoiding localized overheating or condensation and creating ideal thermodynamic conditions for subsequent distillation. The steam pressure in the middle stage (0.045-0.055 MPa) maintains efficient distillation of alcohol and aroma compounds. The steam temperature corresponding to this pressure (105-108℃) is within the optimal distillation temperature range, ensuring both complete vaporization of alcohol (boiling point 78.3℃) and preventing the thermal decomposition of aroma compounds (the decomposition temperature of most esters is between 180-220℃). According to Raoult's law and Dalton's law of partial pressures, under these temperature and pressure conditions, the vapor pressure of alcohol is approximately 0.12 MPa, and the vapor pressure of aroma compounds is approximately 0.005-0.015 MPa. The ratio of these two vapor pressures to the total pressure (0.045-0.055 MPa) determines the distillation selectivity. The relative volatility of alcohol is approximately 2.2-2.5, and the relative volatility of aroma compounds is approximately 0.1-0.3, ensuring that alcohol is preferentially distilled while aroma compounds are extracted at an appropriate rate, without loss due to excessively fast distillation. After the final vapor pressure decreases to below 0.02 MPa, the distillation driving force decreases, but the residence time of steam within the material layer increases. The mass transfer process changes from rapid distillation to slow extraction. The low concentration of alcohol (3-5% vol) and aroma compounds (200-300 mg / L) remaining in the mash have more time to transfer from the liquid phase to the gas phase, significantly improving the extraction rate. The final stage material removal technology increased the porosity of the material layer from 35% to 48%. According to the Kozeny-Carman equation, permeability is proportional to the cube of porosity. A 37% increase in porosity leads to an approximately 1.6-fold increase in permeability, a reduction of approximately 38% in steam penetration resistance, more uniform steam flow, increased contact area between the mash particles and steam, improved mass transfer coefficient, and a significant improvement in final stage extraction efficiency. Under these combined effects, the alcohol extraction rate increased from 82.3% using traditional methods to 86.7%, an increase of 4.4 percentage points; the aroma substance extraction rate increased from below 80% to above 85%, an increase of over 6%.

[0081] Experiment Example 3: Multi-round Fit Verification Experiment This embodiment verifies the applicability and stability of the three-stage steaming operation method combined with the final stage material removal technology in different distillation rounds.

[0082] The production process for Maotai-flavor baijiu is the 12987 process, which involves a one-year production cycle, two rounds of feeding, nine rounds of steaming and cooking, eight rounds of fermentation, and seven rounds of distillation. The characteristics of the mash vary significantly between different rounds: the first round has a high starch content (approximately 35-40%), low saccharification and fermentation levels, and a relatively low alcohol content (approximately 4-5% vol); the third round is the core round, with fully fermented mash, high alcohol content (approximately 6-7% vol), and rich aroma compounds; the fifth round is a transition round, with the acidity of the mash beginning to increase (pH approximately 3.8-4.0) and a medium alcohol content (approximately 5-6% vol); the seventh round has high acidity (pH approximately 3.5-3.8), low alcohol content (approximately 4-5% vol), but a complex variety of aroma compounds.

[0083] This embodiment selects four representative rounds: one, three, five, and seven rounds. For each round, the three-stage stilling operation method combined with the final stage of material removal was applied. The operating parameters and technical requirements were exactly the same as in Experiment 1. Three repeated stills were conducted for each round, recording key indicators such as base liquor yield, alcohol content, and aroma substance content. These results were compared with control data from the round using the traditional empirical stilling method.

[0084] Specifically: 1. Implementation content: To verify the applicability and stability of the three-step manual steaming method in different distillation rounds.

[0085] 2. Implementation method: The method was applied to mash with different characteristics through multiple rounds of comparative experiments.

[0086] 3. Comparison content: Focus on examining the increase in base liquor production and alcohol content in each batch.

[0087] 4. Verification criteria: The technical indicators can be steadily improved in each round, and the performance is the best in the core round.

[0088] 5. Implement work teams: Maintain consistency in the allocation of experimental personnel.

[0089] 6. Specific process: Round selection: Select four representative rounds: Round 1 (high starch characteristics), Round 3 (core round), Round 5 (transition round), and Round 7 (high acidity characteristics).

[0090] Experimental execution: The three-stage steaming method was applied to the mash from each batch, and the results were compared with the traditional method.

[0091] - Data recording: The system records key indicators such as production volume and alcohol content for each round.

[0092] 7. Implementation Data: The results obtained through multiple rounds of system experiments are shown in Table 4 below: Table 4

[0093] Note: Yield increase rate, alcohol content increase rate, and overall aroma compound increase rate are all relative to the traditional empirical method for this batch. The overall aroma compound increase rate is the weighted average of the increase rates of the three main esters: ethyl lactate, ethyl acetate, and ethyl hexanoate. Applicability evaluation is based on a comprehensive assessment of indicators such as yield, quality, and operational stability.

[0094] As shown in Table 4, the technology of this invention can consistently improve the yield and quality of base liquor in different rounds. The yield improvement rate in each round is between 3.1% and 4.2%, the alcohol content improvement is between 1.6% and 2.3% vol, and the comprehensive improvement rate of aroma substances is between 7.2% and 13.2%. Particularly in the core third round, the yield improvement rate reaches 4.2%, the alcohol content improvement is 2.3% vol, and the comprehensive improvement rate of aroma substances reaches 13.2%, showing the most significant effect. The reason for the optimal effect in the third round is that the mash fermented in the third round is sufficient, with high alcohol content and aroma substance content, resulting in greater potential for distillation extraction. Through the optimization of the three-stage operation method and the final stage material removal technology, the improvement in extraction efficiency leads to the most significant improvement in yield and quality. The first and seventh rounds have relatively lower alcohol content and relatively smaller extraction potential, but the yield improvement rates still reach 3.5% and 3.1% respectively, indicating that the technology of this invention also has a significant improvement effect on low-alcohol mash. The fifth round is in the middle state, with a yield improvement rate of 3.8%, showing good results.

[0095] The technical significance of verifying the adaptability to different fermentation batches lies in demonstrating that the technology of this invention is not dependent on the characteristics of mash in a specific batch and is applicable to mash with different fermentation degrees, alcohol contents, and acidities, thus possessing broad promotional value. In actual production, the characteristics of mash vary from batch to batch, but the standardized parameter system of the three-stage operation method and the core principle of the final stage material removal technology are universal. Stable technical results can be achieved simply by fine-tuning operational details based on specific conditions such as the moisture content and bulk density of the mash. This adaptability and stability are difficult to achieve with traditional empirical methods. Traditional methods rely on operators' experience in judging the characteristics of mash in different batches, leading to significant differences between different personnel and work groups. In contrast, the technology of this invention, through standardized processes and quantitative parameter control, significantly reduces reliance on individual experience and improves the controllability and repeatability of production.

[0096] Overall implementation results: Through systematic experimental verification and data analysis, this invention has demonstrated significant technological advantages. In terms of base liquor yield, the average increase reached 4.0%, with an increase of 4.5 kg per still. Regarding base liquor quality, alcohol content stability improved by 33.3%, and the content of key aroma compounds increased by 9.6%-12.1%. In terms of operational stability, fluctuations in the stilling speed decreased by 40%, and the uniformity of the grain layer improved by 10%. These data fully demonstrate the scientific validity, practicality, and promotional value of this technology.

[0097] The successful implementation of this technology not only solved the technical difficulties of the traditional steaming process, but also provided reliable technical support for the standardization and intelligent development of Maotai-flavor liquor production. By establishing standardized operating procedures and a quality control system, it significantly reduced reliance on operator experience, improved production efficiency and product quality stability, and has important implications for industry promotion.

[0098] It is understood that this application has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of this application. Furthermore, based on the teachings of this application, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of this application. Therefore, this application is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of this application.

Claims

1. A method for steaming a type of soy sauce-flavored baijiu (Chinese liquor), characterized in that, This includes the initial bottom-laying stage, the middle main distillation stage, and the final capping stage, which are carried out in sequence: The initial bottom-laying stage includes: after preheating the still with steam, spreading the mash to be added on the still grate to form 1-3 layers, each layer with a thickness of 3-4cm, and controlling the steam pressure to be 0.045~0.055MPa; The main distillation stage in the middle section includes: on the material layer formed in the initial stage, the mash to be added is spread again, with 4-17 layers, each layer thickness controlled at 2-4cm, the steam pressure is maintained at 0.045~0.055MPa, and the feeding speed and steam exit speed are controlled to be synchronized. The total duration of this stage is controlled at 35-40 minutes. The final sealing stage includes: when the material layer reaches 80% of the height of the still, the steam pressure is reduced to ≤0.02MPa, the thickness of each layer is controlled at 1-2cm, and the mash to be fed is loosened before being fed into the still to the mouth of the still.

2. The method for steaming soy sauce-flavored Baijiu according to claim 1, characterized in that, In the initial stage of spreading the mash, the specific parameters for steam preheating are as follows: open the steam valve to preheat the still for 5 minutes, control the steam pressure at 0.08-0.10MPa, and turn off the steam after preheating before spreading the mash.

3. The method for steaming soy sauce-flavored Baijiu according to claim 1, characterized in that, During the main distillation stage in the middle section, after every two layers of material are laid, a detection tool is used to check the porosity of the material layer.

4. The method for steaming soy sauce-flavored Baijiu according to claim 3, characterized in that, The detection tool is a metal probe with a diameter of 1 cm and a length of 50 cm.

5. The method for steaming soy sauce-flavored Baijiu according to claim 1, characterized in that, During the final capping stage, a loosening tool is used to loosen and remove the mash, and the loosened mash is placed in a lifting container for use by the steaming personnel.

6. The method for steaming soy sauce-flavored Baijiu according to claim 5, characterized in that, The volume of fermented mash after emptying from the container is controlled to be less than two-thirds of the container's capacity.

7. The method for steaming soy sauce-flavored Baijiu according to claim 1, characterized in that, The initial stage of laying the base also includes: before spreading the mash to be added, pouring the reserved tail liquor into the earthen pot.

8. The method for steaming soy sauce-flavored Baijiu according to any one of claims 1-7, characterized in that, The steaming operation in the main distillation stage of the middle section follows the principle of steam pressure, that is, the steaming speed is adjusted according to the steam outflow speed so that the steam just penetrates the newly laid material layer.

9. The method for steaming soy sauce-flavored Baijiu according to any one of claims 1-7, characterized in that, The steaming operation in the final capping stage follows the principle of steam pressure reduction, and the steaming speed decreases synchronously with the decrease of steam pressure.

10. The application of the steaming method for soy sauce-flavored baijiu according to any one of claims 1-9 in the production of baijiu base liquor.

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