Fen-flavor liquor fermentation process based on Ru porcelain glaze modified ground vat

Abstract

The invention discloses a fen-flavor liquor fermentation process based on a Ru porcelain glaze modified ground vat, and belongs to the technical field of liquor fermention.The fen-flavor liquor fermentation process comprises the key links of ground vat pretreatment, fermentation pit arrangement, raw material treatment, vat fermentation, distillation purification, ageing quality improvement and the like, and the modified ground vat is formed by adopting a customized glaze formula and firing in a high-temperature reducing atmosphere; and a fine ice crack hacking structure is formed on the glaze surface. According to the method, the advantages of release, catalysis and adsorption of trace elements of Ru porcelain glaze are fully played by optimizing the performance of a ground cylinder, precisely regulating and controlling the fermentation environment and adopting a steaming secondary distillation process, so that the fermentation process is stable and controllable, infectious microbe pollution is inhibited, and the starch conversion rate and the wine liquid purity are improved; therefore, the white spirit has the style characteristics of faint scent, purity, softness, sweetness and cleanness and rich flavor levels, the high-quality faint scent white spirit with unique Ru porcelain process characteristics is formed, and the product quality and the market competitiveness are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of baijiu fermentation technology, specifically to a light-aroma baijiu fermentation process based on Ru porcelain glaze-modified earthen vats. Background Technology

[0002] As one of the four basic aroma types of baijiu in my country, light-aroma baijiu is characterized by its "pure and refreshing aroma, smooth and sweet taste." Its production process follows the core principle of "one clearing and two clearings," placing extremely high demands on the sealing, permeability, chemical stability, and flavor control capabilities of the fermentation containers. Traditional light-aroma baijiu fermentation often uses ordinary earthenware vats. The glaze composition of these vats is limited, only providing basic fermentation space, which presents several technical drawbacks: Firstly, ordinary earthenware glazes lack corrosion resistance and stability, and prolonged contact with organic acids in the mash can easily cause glaze peeling, leading to contamination by miscellaneous bacteria and affecting the purity of the baijiu. Secondly, ordinary earthenware vats lack the ability to release special trace elements, making it impossible to control the microbial fermentation process through container characteristics, hindering the formation of a unique flavor profile. Furthermore, the poor temperature compatibility between the vat and the fermentation pit easily leads to fluctuations in fermentation temperature, affecting the yield and consistency of quality.

[0003] Ru ware, considered the foremost of the five great kilns of the Song Dynasty in my country, possesses a unique glaze composition characterized by high aluminum and low silicon due to the addition of special ingredients such as agate powder. After firing, this results in a fine, crackled structure that combines excellent breathability and sealing properties, while also slowly releasing various beneficial trace elements. However, the original Ru ware glaze suffers from issues such as a mismatch between the body and glaze expansion coefficients and insufficient acid resistance, making it unsuitable for the complex environment of baijiu fermentation. Therefore, glaze modification is necessary to optimize its performance.

[0004] Existing technologies for baijiu fermentation and related containers primarily focus on optimizing sealing structures, adjusting raw material ratios, or improving distillation processes. They rarely integrate Ru ware glaze modification technology with earthen vat fermentation, and lack a complete and compatible process from vat pretreatment and raw material processing to fermentation, distillation, and aging. Furthermore, existing technologies suffer from insufficient compatibility with Ru ware-modified earthen vats in aspects such as fermentation environment control, sealing method selection, and auxiliary material matching, making it difficult to fully leverage the advantages of Ru ware glaze. Therefore, developing a light-aroma baijiu fermentation process based on Ru ware glaze-modified earthen vats to address the shortcomings of traditional processes and improve baijiu quality and production stability has become an urgent need within the industry. Summary of the Invention

[0005] This invention aims to overcome the shortcomings of existing light-aroma baijiu fermentation processes, such as insufficient performance of ordinary earthen vats, difficulty in controlling the fermentation environment, and difficulty in achieving breakthroughs in flavor and quality. It provides a light-aroma baijiu fermentation process based on earthen vats modified with Ru porcelain glaze. By optimizing the entire process, including vat pretreatment, raw material processing, fermentation sealing, distillation, and aging, the invention fully leverages the advantages of Ru porcelain glaze-modified earthen vats in releasing trace elements, catalysis, and heat preservation and sealing. This achieves a stable and controllable fermentation process, improves the baijiu yield, purity, and flavor profile, and creates a light-aroma baijiu with unique Ru porcelain craftsmanship characteristics.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a fermentation process for light-aroma baijiu based on Ru porcelain glaze-modified earthen vats, comprising... S1: The pre-made Ru porcelain glaze modified earthenware jar is vertically buried in the underground fermentation pit, with the mouth of the jar flush with the ground. The gap between the side wall and bottom of the jar and the fermentation pit is filled with a mixed insulation layer. The mixed insulation layer is made by mixing river sand, perlite and Ru porcelain powder in a mass ratio of 3:1:0.5, with a filling thickness of 20-30cm. S2: Select red sorghum, barley, and peas as fermentation raw materials, mix them in a 7:2:1 mass ratio, crush them to a particle size of 2-4mm, add 55-60% purified water of the total raw material mass, stir evenly, and moisten at room temperature for 12-16 hours, turning them over once every 4 hours during the moistening process; then steam them using the steaming method at a temperature of 100-105℃ for 60-90 minutes until the raw materials are thoroughly cooked and not gelatinized. After removing them from the steamer, quickly spread them out to cool to 28-32℃, spraying 0.5% sterile water of the total raw material mass during the cooling process to maintain the moisture content of the raw materials at 45-48%; S3: Add 8-12% of the total mass of the light-fragrant medium-temperature koji to the cooled raw materials, stir evenly, and then put it into the pre-treated Ru porcelain glaze modified earthenware vat. The filling height of the vat should be 70-75% of the vat volume. After filling, compact the mixture and seal it for fermentation. S4: After fermentation, the mash in the vat is removed and distilled using a two-stage distillation process at a temperature of 95-100℃. In the first distillation, the initial distillate is collected. First, 2-3% of the total distillate is collected as the heads, then the middle section with an alcohol content of 60-65% vol is collected as the base liquor, and finally 10-15% of the tails are collected. In the second distillation, the heads, tails and initial distillate are mixed evenly and then redistilled. The distillation time is extended by 15-20 minutes compared to the first distillation. The flavored baijiu is produced by modifying the vat with Ru porcelain glaze. As a further preferred embodiment of this technical solution: S1: Pretreatment of earthen vats and layout of fermentation pits Pre-made Ru porcelain glaze-modified earthenware jars are vertically buried in underground fermentation pits, with the jar opening flush with the ground to ensure even stress distribution and prevent tilting or leakage during fermentation. The depth of the underground fermentation pit is 30-40cm higher than the height of the earthenware jars. The pit walls are first leveled with cement mortar, then a 5-8mm thick layer of Ru porcelain glaze is applied. The coating is dried and cured at 800-850℃, which significantly improves the sealing and corrosion resistance of the pit walls, preventing the invasion of soil bacteria and water penetration.

[0007] A mixed insulation layer is filled in the gaps between the side walls and bottom of the earthen vat and the fermentation pit. This mixed insulation layer is made of river sand, perlite, and Ru porcelain powder mixed in a mass ratio of 3:1:0.5, with a filling thickness controlled at 20-30cm. The river sand and perlite ensure the structural stability and thermal insulation performance of the insulation layer, while the Ru porcelain powder complements the modified earthen vat, further optimizing the local microbial environment.

[0008] After the earthen vat is buried, its inner wall is sterilized by high-pressure steam. The steam pressure is controlled at 0.1-0.15MPa and the temperature is 120-150℃. The temperature is maintained for 2-3 hours. After the steam is turned off, it is allowed to cool naturally to room temperature. During this period, a slight negative pressure is maintained inside the vat to prevent external impurities from being adsorbed into the vat through the glaze cracking network, thus ensuring a sterile initial fermentation environment. As a further preferred embodiment of this technical solution: S2: Raw material processing, Red sorghum, barley, and peas were selected as fermentation raw materials and mixed in a 7:2:1 mass ratio. Red sorghum has a high amylopectin content, which can improve the alcohol yield and the smoothness of the liquor; barley and peas provide rich protein and enzyme precursors, optimizing the fermentation effect of the starter culture. The mixed raw materials were crushed to a particle size of 2-4mm. This particle size ensures that the raw materials fully absorb water and gelatinize during the subsequent wetting and cooking processes, while avoiding poor aeration of the mash due to excessively fine particle size.

[0009] Add 55-60% purified water by weight of the pulverized raw material, stir well, and moisten at room temperature for 12-16 hours. During the moistening process, stir every 4 hours to ensure that the raw material absorbs water evenly and avoid local dryness or water accumulation. Then, steam the raw material at a temperature of 100-105℃ for 60-90 minutes until it is thoroughly cooked and does not gelatinize. This process destroys anti-nutritional factors in the raw material while preserving starch conversion activity.

[0010] After the raw materials are removed from the pot, they are quickly cooled to 28-32℃. During the cooling process, 0.5% of the total mass of the raw materials is sprayed with sterile water to maintain the moisture content of the raw materials at 45-48%, so as to provide a suitable moisture environment for subsequent Daqu inoculation and microbial fermentation. As a further preferred embodiment of this technical solution: S3: Ferment in a vat Add 8-12% of the total mass of light-aroma medium-temperature koji to the cooled raw materials, stir evenly, and then put it into the pre-treated Ru porcelain glaze modified earthenware vat. The filling height should be 70-75% of the vat volume. After filling, gently compact the vat to ensure that the mash is in full contact with the inner wall of the vat, while leaving some pores for microbial respiration and metabolism.

[0011] The light-aroma type medium-temperature koji is hand-made by foot-feeding. It is made by mixing barley and peas in a 1:1 mass ratio, inoculating it with a special koji strain for light-aroma baijiu (mainly containing dominant microbial groups such as yeast, lactic acid bacteria, and molds), and cultivating it for 25-30 days at 28-32℃ and 70-75% humidity. After maturation, it is pulverized to 80-100 mesh for later use. Its saccharification power is ≥300U / g and liquefaction power is ≥200U / g, which can efficiently decompose starch and protein in raw materials to generate alcohol and flavor substances.

[0012] After filling the fermentation tanks, a double-layer sealing structure is used for airtight fermentation: the inner layer is a food-grade silicone sealing gasket that fits tightly to the tank opening to ensure basic sealing; the outer layer is a cotton-linen cloth coated with beeswax to further enhance the sealing effect, while the beeswax can slowly release a faint aroma to help enhance the flavor of the wine. After sealing, a circular water trough is built around the edge of the tank opening and filled with sterile water to form a water seal, completely preventing air from entering and preventing contamination by other microorganisms.

[0013] During fermentation, the ambient temperature is controlled at 18-22℃ and the soil moisture at 60-65%, with a fermentation cycle of 28-35 days. Utilizing the trace elements (such as calcium, magnesium, and iron) released from the modified glaze layer of Ru porcelain and their catalytic effect, the fermentation process of the mash is regulated. Samples are taken every 5 days to test the temperature, pH value, and microbial community of the mash, maintaining a pH value of 3.8-4.5 to ensure that the dominant microbial community of yeast and lactic acid bacteria accounts for ≥90%, inhibiting the growth of harmful bacteria, and directionally generating characteristic flavor substances of light-aroma baijiu such as ethyl acetate. As a further preferred embodiment of this technical solution: S4: Distillation and purification After fermentation, the mash is removed from the vat and distilled using a double-distillation process, with the distillation temperature controlled at 95-100℃ to avoid the decomposition of flavor compounds due to high temperatures. The first distillation collects the initial distillate, first taking 2-3% of the total distillate (containing high-boiling-point impurities, with a pungent taste), then taking the middle section (60-65% vol) as the base spirit (pure flavor, fewer impurities), and finally collecting 10-15% of the tails (containing low-boiling-point impurities, with a mellow taste but insufficient aroma).

[0014] Before the second distillation, 3-5% by weight of Ru porcelain fragments (5-8mm in diameter) are added to the mixture of the heads, tails, and initial distillate. These fragments, consistent with the modified earthenware glaze formula, remove impurities from the mixture during the second distillation through adsorption. Simultaneously, the released trace elements further optimize the flavor and improve the overall taste harmony. The second distillation time is extended by 15-20 minutes compared to the first distillation to ensure thorough separation of impurities and achieve the required purity. As a further preferred embodiment of this technical solution: The distilled flavored baijiu needs to be aged in Ru porcelain glaze-modified earthenware jars. These jars are made using the same glaze formula and firing process as the modified earthenware vats, thus continuing the optimizing effect of Ru porcelain glaze on the liquor. The aging process is controlled at a temperature of 15-18℃ and a humidity of 60-65%, with an aging time of no less than 8 months. During the aging period, the jars are turned once a month to promote esterification balance, accelerate the volatilization of pungent substances, and enhance the smoothness and flavor complexity of the liquor, ultimately yielding a high-quality light-aroma baijiu. As a further preferred embodiment of this technical solution: The glaze formula for the Ru porcelain glaze-modified earthenware vase, by weight percentage, is as follows: 15-20% agate powder, 22-28% kaolin, 16-20% quartz sand, 10-14% alumina powder, 4-6% calcium oxide, 1.5-2.5% magnesium oxide, 2-4% nano-zirconia modifier, and the balance being deionized water. The nano-zirconia modifier can improve the density and acid resistance of the glaze layer, solving the problem of the mismatch between the expansion coefficients of the original Ru porcelain glaze and the body.

[0015] The glaze thickness is controlled at 1.0-1.5mm and fired in a reducing atmosphere at 1260-1300℃. After firing, the glaze surface forms a fine ice crack structure, which has both air permeability and sealing properties. It can release carbon dioxide produced during fermentation and prevent external bacteria from invading. At the same time, it slowly releases trace elements to regulate the fermentation process.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention fully leverages the advantages of Ru porcelain glaze modification: by customizing the glaze formula and firing process, the performance defects of the original Ru porcelain glaze are solved. The modified earthenware vat has good sealing, air permeability, corrosion resistance and trace element release ability. Combined with exclusive fermentation, distillation and aging processes, it achieves deep adaptation between container characteristics and process links, and specifically enhances the flavor of baijiu. 2. In this invention, the fermentation process is stable and controllable with a low rate of contamination by miscellaneous bacteria: Through the design of high-pressure steam sterilization, double-layer sealed water seal, glaze coating of fermentation pit and mixed heat preservation layer, a sterile, constant temperature and humidity fermentation environment is constructed, maintaining the proportion of dominant bacteria such as yeast and lactic acid bacteria ≥90%, reducing the contamination rate of miscellaneous bacteria to below 1%, and ensuring the purity of the wine. 3. Relying on the adsorption and catalytic effects of Ru porcelain glaze and fragments, impurities in the wine are effectively removed, the composition of flavor substances is optimized, and the wine is fragrant, pure, mellow, sweet and refreshing with rich flavor layers. At the same time, the stable fermentation environment improves the starch conversion rate and increases the wine yield. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the fermentation process of light-aroma baijiu based on Ru porcelain glaze modified earthenware vats according to the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example Please see Figure 1 As shown, the present invention provides a technical solution: Example 1 This embodiment provides a fermentation process for light-aroma baijiu based on Ru porcelain glaze-modified earthen vats. The specific operation process and details are as follows: Pretreatment of earthen vats and layout of fermentation pits First, the prefabrication of the Ru porcelain glaze-modified earthenware vase is completed. The glaze is precisely proportioned according to the corresponding mass percentage range, and core raw materials such as agate powder, kaolin, and quartz sand are selected, with nano-zirconia modifier added to optimize performance. During preparation, the solid raw materials are first put into an ultra-micro pulverizer and pulverized into fine powder to ensure uniform mixing and sufficient adhesion of the glaze to the body. After adding the modifier, the glaze is wet-ground to control the slurry concentration within an appropriate range. After standing and aging to remove air bubbles, the glaze is then evenly applied to the surface of the vase body using a spray glaze method. The thickness of the glaze layer is strictly controlled within the set range to avoid cracking due to excessive thickness or the inability to form a complete crazing structure due to excessive thinness. The glazed earthenware jars were then placed in a tunnel kiln and fired in a segmented temperature-controlled reducing atmosphere. The temperature was raised to the target firing temperature at a set rate and then kept at a constant temperature. During the firing process, the carbon monoxide concentration was controlled within a reasonable range to ensure that the glaze was fully melted and formed fine ice crack patterns. After cooling, a modified earthenware jar with a smooth glaze and uniform crack patterns was obtained. The body was a typical "incense ash body," and the air permeability and sealing met the requirements for fermentation.

[0020] The underground fermentation pit is excavated in advance, with a depth 30-40cm higher than the height of the fermentation vat. A compacted clay layer is laid at the bottom of the pit to prevent water seepage. The pit walls are leveled with qualified cement mortar, and after curing, a Ru porcelain glaze coating of a predetermined thickness is laid. The coating material is the same as the glaze of the fermentation vat, and it is dried and cured at the corresponding temperature. After curing, the pit wall surface is smooth and non-porous, effectively preventing the invasion of miscellaneous bacteria and moisture from the soil. The prefabricated fermentation vat is vertically hoisted into the fermentation pit, and its position is adjusted so that the vat opening is flush with the ground to ensure even stress distribution. The gap between the fermentation vat and the fermentation pit is filled with an insulation layer made of river sand, perlite, and Ru porcelain powder mixed in a predetermined ratio. The river sand is washed, impurities removed, and dried. The perlite is selected with an appropriate particle size, and the Ru porcelain powder is made from the scraps of the fermentation vat. The filling thickness is controlled within the predetermined range, and the layers are compacted to ensure a dense and gapless structure, balancing insulation stability and material synergy.

[0021] After the terrazzo tank is buried, it undergoes high-pressure steam sterilization. A steam pipe is connected to the sealed opening inside the tank, and high-pressure steam is introduced and maintained within the set pressure and temperature range for the corresponding duration. This process thoroughly kills bacteria without damaging the glaze structure. After sterilization, the steam valve is closed, maintaining a slight negative pressure inside the tank, and it is allowed to cool naturally to room temperature. During cooling, the tank opening must not be opened to prevent the adsorption of bacteria. Once cooled and the tank is found to be sterile, it can proceed to the next step.

[0022] Raw material processing High-quality red sorghum, barley, and peas are selected as fermentation raw materials and mixed according to a set mass ratio. The red sorghum must meet the standards for amylopectin, moisture, and impurity content. The barley and peas are screened to remove unqualified particles and impurities. The mixed raw materials are put into a grinder and ground to a particle size range of 2-4mm. The grinding parameters are controlled to ensure uniform particle size, which guarantees the subsequent wetting and cooking effect. Purified water of a set proportion is added to the ground raw materials and stirred evenly with a stainless steel agitator. Then, the materials are wetting for the corresponding time in a constant temperature and humidity environment. During the wetting process, the materials are turned at set intervals using sterile wooden tools to avoid damaging the raw material structure and preventing contamination by bacteria. After wetting, the moisture content of the raw materials reaches a suitable state, preparing them for cooking and gelatinization.

[0023] The moistened raw materials are placed into a bamboo steamer and steamed using a controlled steaming method. The steam introduction rate is controlled to maintain a stable cooking temperature within the set range, and the temperature is maintained for the corresponding duration to ensure the raw materials are thoroughly cooked without becoming gelatinized. After steaming, the raw materials have no uncooked core, no burnt taste, and a suitable texture. Once removed from the steamer, the raw materials are quickly transferred to a sterile cooling bed. The thickness of the cooling layer is controlled, and forced ventilation is used for cooling, while simultaneously controlling the ambient temperature to prevent contamination by other microorganisms. When the raw material temperature drops to the set range, a predetermined proportion of sterile water is evenly sprayed while stirring to ensure uniform moisture distribution, ultimately maintaining the raw material moisture content between 45% and 48%.

[0024] The moistened raw materials are placed into a bamboo steamer and steamed using a steaming method with a steam introduction rate of 2m. 3 The cooking temperature is maintained at 102℃ for 75 minutes. During the cooking process, the raw material's condition needs to be observed regularly. The first 30 minutes are the heating stage, the middle 30 minutes are the gelatinization stage, and the last 15 minutes are the thorough cooking stage. Ensure the raw material is thoroughly cooked without gelatinizing. The cooked raw material will turn a light yellow color, with no raw core or burnt smell, and can be kneaded by hand to form a fine paste-like structure. After removing the raw material from the pot, it should be quickly transferred to a sterile cooling bed, with a thickness controlled at 5cm. Forced ventilation using a fan is employed for cooling at a rate of 1.5m / s. 3 / (m 2 During the cooling process, the ambient temperature is controlled at 28℃ to prevent contamination by other microorganisms. When the raw material temperature drops to 30℃, 0.5kg of sterile water is sprayed evenly while stirring to ensure uniform moisture distribution. The final moisture content of the raw material is maintained at 46%, which is suitable for Daqu inoculation. This satisfies the moisture requirements for microbial growth without causing the mash to spoil due to excessive moisture.

[0025] Fermentation in a vat Add a predetermined proportion of light-aroma medium-temperature koji to the cooled raw materials. This koji is handmade by foot-feeding, and is a mixture of barley and peas in a 1:1 mass ratio. It is then inoculated with a special koji strain for light-aroma baijiu and cultured for the specified time under a set temperature and humidity environment. After maturation, it is pulverized and sieved to the predetermined fineness, ensuring that the enzyme activity meets fermentation requirements. After adding the koji, use sterile stirring equipment to mix evenly, ensuring full contact between the koji and the raw materials and avoiding uneven concentration in certain areas that could affect fermentation efficiency.

[0026] The mixed raw materials are loaded into the pretreated modified fermentation vat, with the filling height controlled between 70-75% of the vat's volume. A layered filling and compaction method is used, ensuring each layer is of uniform thickness and gently compacted with a sterile wooden press plate, balancing the contact between the raw materials and the vat wall with the aeration of the mash. After filling, a double-layered sealed fermentation structure is employed: the inner layer is lined with a food-grade silicone sealing gasket, its size perfectly matched to the vat opening without wrinkles; the outer layer is covered with beeswax-coated cotton or linen cloth, its edges extending to a suitable length beyond the vat's outer edge, enhancing the sealing effect and contributing to flavor enhancement. After sealing, a circular water trough is constructed around the vat's edge, filled with sterile water to form a water seal, completely isolating air and other microorganisms.

[0027] During fermentation, the fermentation environment temperature and soil moisture are strictly controlled within a set range, with the fermentation cycle being suitable within the range of 28-35 days. Utilizing the beneficial trace elements released from the modified earthenware vat glaze and the breathable characteristics of its open-crack structure, the fermentation process of the mash is regulated. Samples are taken at set intervals during this period, using a sterile sampler to collect and mix samples from different depths within the vat. The temperature, pH value, and microbial community of the mash are tested to ensure stable fermentation temperature, pH value maintained within the range of 3.8-4.5, a dominant yeast and lactic acid bacteria ratio of ≥90%, and the detection of no harmful bacteria, thus promoting the targeted generation of characteristic flavor substances in light-aroma baijiu.

[0028] Distillation and aging for quality improvement After fermentation, the mash is removed and distilled twice using a steaming process, with the distillation temperature controlled within a set range to avoid damaging flavor compounds. The first distillation collects the initial distillate, separating the heads and tails in a specific ratio, and collecting the middle section (with the corresponding alcohol content) as the base spirit. Before the second distillation, a set proportion of Ru ware porcelain fragments are added to the mixture of the heads, tails, and initial distillate. The fragments meet the required particle size and are pre-sterilized. The re-distillation time is extended by the corresponding amount from the first distillation, utilizing the Ru ware porcelain fragments to absorb impurities and optimize the flavor. After distillation, the spirit is poured into Ru ware glaze-modified earthenware jars for aging, with the aging temperature and humidity controlled within a set range for at least 8 months. During this period, the jars are turned at set intervals to promote esterification balance, enhance smoothness and flavor complexity, ultimately yielding a high-quality light-aroma baijiu with a significantly higher yield than traditional processes.

[0029] Example 2 The difference between this embodiment and Embodiment 1 is that the Ru porcelain glaze formula is adjusted to the lower limit of a set range, the glaze thickness is controlled at the minimum value within the range, and a reducing atmosphere at the corresponding lower limit temperature is used for firing; the fermentation cycle is taken as the minimum value within the set range, and the aging time is controlled according to the minimum requirements. The final produced baijiu has a rich and fragrant aroma, low impurity content, meets the standards for high-quality light-aroma baijiu, and the yield is increased by the set lower limit compared to the traditional process, verifying the stability of this process under low parameter combinations.

[0030] The difference between this embodiment and Embodiment 1 is as follows: the Ru porcelain glaze formula consists of 15% agate powder, 28% kaolin, 20% quartz sand, 10% alumina powder, 6% calcium oxide, 1.5% magnesium oxide, 2% nano-zirconia modifier, and 17.5% deionized water; the glaze thickness is 1.0 mm; firing is carried out at 1260℃ in a reducing atmosphere; the fermentation period is 28 days; and the aging time is 8 months. The resulting baijiu has a rich and fragrant aroma, low impurity content, meets the standards for high-quality light-aroma baijiu, and increases the yield by 8%.

[0031] Example 3 The difference between this embodiment and Embodiment 1 is that the Ru porcelain glaze formula is adjusted to the upper limit of the set range, the glaze thickness is controlled at the maximum value of the range, and a reducing atmosphere at the corresponding upper limit temperature is used for firing; the amount of Ru porcelain fragments added during secondary distillation is the maximum value of the set range, and the aging time is extended to the upper limit of the set range. The resulting baijiu has a richer flavor profile, better smoothness, and the yield is increased by the upper limit of the set range compared to the traditional process, demonstrating the quality improvement effect of this process under high parameter combinations.

[0032] The difference between this embodiment and Embodiment 1 is as follows: the Ru porcelain glaze formula consists of 20% agate powder, 22% kaolin, 16% quartz sand, 14% alumina powder, 4% calcium oxide, 2.5% magnesium oxide, 4% nano-zirconia modifier, and 17.5% deionized water; the glaze thickness is 1.5 mm, and it is fired at 1300℃ in a reducing atmosphere; 5% Ru porcelain fragments are added during secondary distillation, and the aging time is 10 months. The resulting baijiu has a richer flavor profile, better smoothness, and a 12% higher yield.

[0033] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A fermentation process for light-aroma baijiu based on Ru porcelain glaze-modified earthenware vats, characterized in that: include S1: The pre-made Ru porcelain glaze modified earthenware jar is vertically buried in the underground fermentation pit, with the mouth of the jar flush with the ground. The gap between the side wall and bottom of the jar and the fermentation pit is filled with a mixed insulation layer. The mixed insulation layer is made by mixing river sand, perlite and Ru porcelain powder in a mass ratio of 3:1:0.5, with a filling thickness of 20-30cm. S2: Select red sorghum, barley, and peas as fermentation raw materials, mix them in a 7:2:1 mass ratio, crush them to a particle size of 2-4mm, add 55-60% purified water of the total raw material mass, stir evenly, and moisten at room temperature for 12-16 hours, turning them over once every 4 hours during the moistening process; then steam them using the steaming method at a temperature of 100-105℃ for 60-90 minutes until the raw materials are thoroughly cooked and not gelatinized. After removing them from the steamer, quickly spread them out to cool to 28-32℃, spraying 0.5% sterile water of the total raw material mass during the cooling process to maintain the moisture content of the raw materials at 45-48%; S3: Add 8-12% of the total mass of the light-fragrant medium-temperature koji to the cooled raw materials, stir evenly, and then put it into the pre-treated Ru porcelain glaze modified earthenware vat. The filling height of the vat should be 70-75% of the vat volume. After filling, compact the mixture and seal it for fermentation. S4: After fermentation, the mash in the vat is removed and distilled using a two-stage steaming process at a temperature of 95-100℃. In the first distillation, the initial distillate is collected. 2-3% of the total distillate is taken as the heads, followed by the middle section with an alcohol content of 60-65% vol as the base liquor. Finally, 10-15% of the tails are collected. In the second distillation, the heads, tails, and initial distillate are mixed evenly and then re-distilled. The distillation time is extended by 15-20 minutes compared to the first distillation. The flavored baijiu is produced by modifying the vat with Ru porcelain glaze.

2. The fermentation process for light-aroma baijiu based on Ru porcelain glaze modified earthenware vats according to claim 1, characterized in that: The modified cylinder in S1 is sterilized by high-pressure steam. The steam pressure is 0.1-0.15MPa and the temperature is 120-150℃. The temperature is maintained for 2-3 hours. After the steam is turned off, it is allowed to cool naturally to room temperature. During this period, a slight negative pressure is maintained inside the cylinder.

3. The fermentation process for light-aroma baijiu based on Ru porcelain glaze modified earthenware vats according to claim 2, characterized in that: In S2, the fermentation environment temperature is controlled at 18-22℃, the soil moisture at 60-65%, and the fermentation cycle is 28-35 days. The fermentation process is regulated by the release and catalytic effect of trace elements in the modified glaze layer of Ru porcelain glaze. During this period, samples are taken every 5 days to test the temperature, pH value and microbial community of the fermented mash, maintaining the pH value at 3.8-4.5 and ensuring that the proportion of yeast and lactic acid bacteria as the dominant microbial community is ≥90%.

4. The fermentation process for light-aroma baijiu based on Ru porcelain glaze modified earthenware vats according to claim 3, characterized in that: The glaze formula of the Ru porcelain glaze modified earthenware vase is as follows by mass percentage: 15-20% agate powder, 22-28% kaolin, 16-20% quartz sand, 10-14% alumina powder, 4-6% calcium oxide, 1.5-2.5% magnesium oxide, 2-4% nano-zirconia modifier, and the balance is deionized water. The glaze thickness is controlled at 1.0-1.5mm and is fired in a reducing atmosphere at 1260-1300℃, resulting in a fine, crackled glaze surface.

5. The fermentation process for light-aroma baijiu based on Ru porcelain glaze modified earthenware vats according to claim 4, characterized in that: The light-aroma medium-temperature koji in S3 is made by hand-stepping, using a 1:1 mass ratio of barley and peas, inoculated with a special koji for light-aroma baijiu, and cultivated for 25-30 days at 28-32℃ and 70-75% humidity. After maturation, it is pulverized to 80-100 mesh for later use, with a saccharification power ≥300U / g and a liquefaction power ≥200U / g.

6. The fermentation process for light-aroma baijiu based on Ru porcelain glaze modified earthenware vats according to claim 5, characterized in that: The closed fermentation in S3 adopts a double-layer sealing structure. The inner layer is a food-grade silicone sealing gasket, and the outer layer is a cotton and linen cloth coated with beeswax. After sealing, an annular water tank is set around the edge of the tank opening, and sterile water is injected to form a water seal.

7. The fermentation process for light-aroma baijiu based on Ru porcelain glaze-modified earthen vats according to claim 6, characterized in that: Before the second distillation in S4, 3-5% of the total mass of Ru porcelain fragments are added to the mixture of the heads, tails and initial distillate. The Ru porcelain fragments have a particle size of 5-8mm. During the re-distillation process, the Ru porcelain fragments adsorb impurities and optimize the flavor of the liquor.

8. The fermentation process for light-aroma baijiu based on Ru porcelain glaze-modified earthen vats according to claim 7, characterized in that: The depth of the underground fermentation pit in S1 is 30-40cm higher than the height of the earthen vat. After the pit wall is plastered with cement mortar, a layer of Ru porcelain glaze coating with a thickness of 5-8mm is laid on it. The coating is dried and cured at 800-850℃ to improve the sealing and corrosion resistance of the pit wall.

9. The fermentation process for light-aroma baijiu based on Ru porcelain glaze modified earthenware vats according to claim 8, characterized in that: The distilled flavored baijiu needs to be aged in Ru porcelain glaze modified earthenware jars at a temperature of 15-18℃ and a humidity of 60-65% for at least 8 months. During the aging period, the earthenware jars are turned once a month to promote the esterification balance of the liquor and enhance its smoothness.

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