Artificial pit mud for improving the rate of high-quality liquor of nine-grain-flavor liquor and preparation method thereof

Abstract

The application discloses artificial pit mud for improving the high-quality liquor rate of nine-grain flavor liquor and a preparation method thereof, and belongs to the technical field of liquor brewing. The pit mud matrix is formed by proportionally compounding loess, mixed attapulgite clay and diatomite, then the pit mud matrix is mixed with fragrant grass medium-temperature starter, pea powder and a nutrition regulator, the mixture is slowly added into pit mud liquid in batches, and after repeated mixing, the mixture is sealed for fermentation to obtain high-quality artificial pit mud. The application constructs a microbe-carrier synergistic ecosystem carrier with a "multi-level structure and function complex" by using loess, mixed attapulgite clay and diatomite, and under the joint action of fragrant grass medium-temperature starter, the nutrition regulator and pit mud liquid, a stable and efficient fragrance-producing ecosystem is quickly constructed, and when the application is applied to nine-grain flavor liquor production, the pit mud fragrance-producing capacity can be significantly improved, rich ethyl hexanoate and other flavor substances can be synthesized, and the yield and proportion of high-quality liquor (special-grade liquor and high-grade liquor) can be improved.

Description

Technical Field

[0001] This invention relates to the field of baijiu brewing technology, specifically to an artificial cellar mud and its preparation method, which is particularly suitable for the production needs of rapidly constructing a stable aroma-producing microbial ecosystem and improving the yield of premium baijiu (special grade and premium grade) and the overall baijiu production rate in the brewing of nine-grain baijiu. Background Technology

[0002] Cellar mud is a crucial fermentation medium in the brewing process of Jiuliangxiang-style baijiu. It serves as both a carrier for functional microorganisms (such as caproic acid bacteria and lactic acid bacteria) and their habitat, directly determining the flavor and overall quality of the baijiu. Traditional cultivation of old cellar mud relies on natural domestication, a lengthy process (often requiring several years or even decades), and high-quality cellar mud resources are scarce. Currently, commonly used artificial cellar mud techniques are mostly based on yellow mud, prepared by adding nutrients and a small amount of old cellar mud culture medium. While this shortens the cultivation time to some extent, it still generally suffers from the following prominent problems: First, the microbial system in traditional loess-based cellar mud is slow to establish, making it difficult to quickly enrich and stabilize the core aroma-producing bacteria. This results in a long maturation period for new cellars, and the content of main aroma substances such as ethyl hexanoate in the base liquor produced is relatively low, with no significant improvement in the yield of premium liquor and the overall liquor output.

[0003] Secondly, the simple pore structure of the pit mud lacks effective adsorption and slow release capabilities, easily leading to an "excessive supply of nutrients in the early stages and insufficient supply in the later stages." This affects the normal succession of the microbial community and the construction of the symbiotic network, causing the pit mud to age prematurely and its aroma-producing function to be unstable. At the same time, under the influence of water infiltration and the compression of the mash, the pore structure is prone to collapse and compaction, reducing air and water permeability. This problem is particularly prominent at the bottom of the pit, severely restricting the aroma-producing efficiency.

[0004] Furthermore, during the peak period of acid production in fermentation, the pit mud has insufficient buffering capacity for acidic substances, and the local pH value is prone to drop rapidly, exceeding the suitable growth range of key functional microorganisms such as caproic acid bacteria (optimal pH 5.5–6.5), thereby causing an imbalance in the microbial community structure.

[0005] In addition, the mud environment created by existing cultivation methods is too homogeneous, which cannot build a diverse habitat microenvironment for different functional microorganisms. This results in a simple microbial community structure and unclear ecological niche differentiation, making it difficult to form a complex and stable microbial symbiotic network like that in old cellar mud.

[0006] Therefore, there is an urgent need to develop an artificial cellar mud and its preparation method that can quickly construct a stable and efficient microbial aroma-producing ecosystem, so as to systematically improve the yield and flavor quality of baijiu. Summary of the Invention

[0007] This invention aims to overcome existing technological bottlenecks by innovatively constructing a composite matrix using loess, mixed attapulgite clay, and diatomaceous earth. Through the directional coupling of its natural multi-level porous structure and complex functional microbial communities, it provides an artificial cellar mud capable of rapidly constructing a stable micro-ecosystem and its preparation method. This technology can significantly improve the yield of high-quality liquor in the Jiuliangxiang (nine-grain) style of baijiu, while simultaneously achieving efficient expression and long-term maintenance of cellar mud functions, providing a novel solution for the micro-ecological regulation of baijiu brewing.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing artificial cellar mud to improve the yield of high-quality liquor in Jiuliang-flavored Baijiu includes the following steps: (1) Preparation of composite matrix: Sichuan loess, mixed attapulgite clay, and diatomaceous earth were selected as raw materials and mixed in a mass ratio of (5-7.5):(1.5-3):(1-2) to form a composite matrix with uniform particle size. Under this ratio, loess serves as the main matrix, combined with the nanoscale rod / sheet structure of mixed attapulgite clay and the hierarchical porous structure of diatomaceous earth, providing a diverse habitat for microorganisms.

[0009] (2) Mixing of auxiliary materials: Add 3% to 8% of the total mass of vanilla medium-temperature koji, 3% to 8% of pea flour, and 0.25% to 0.5% of nutrient regulator to the composite matrix and mix evenly.

[0010] The nutrient regulator is composed of dipotassium hydrogen phosphate, sodium acetate, magnesium sulfate, and yeast extract in a mass ratio of 2:1:1:1, providing carbon, nitrogen, minerals, and growth factors for the growth, reproduction, and metabolism of functional microorganisms in the fermentation pit mud. The vanilla-based medium-temperature koji contains ≥10% vanilla components. This koji is produced by adding vanilla raw materials to the raw material crushing or mixing process in the traditional medium-temperature koji preparation process, followed by a medium-temperature cultivation process (maximum temperature 50-60℃). The finished koji block contains vanilla components (on a dry basis) of not less than 10%. The vanilla raw material is vanilla beans.

[0011] (3) Adding the pit mud liquid: The pit mud liquid prepared by mixing yellow water, wine tails, edible alcohol, and lees liquid in a mass ratio of (5-10):(4-8):(1-3):(30-35) is added to the above mixture in 3-5 batches. The amount added in each batch is 20%-33% of the total pit mud liquid. After each batch is added, stir for 10-20 minutes to ensure that the material is fully soaked and mixed evenly. Then seal with plastic film. Adding in batches can avoid the material clumping caused by excessive local moisture and improve the overall uniformity of the pit mud.

[0012] The alcohol content of the tail liquor is 2-10% vol; the lees liquid is the liquid obtained by mixing the lees (discarded lees) after distillation in the production of baijiu with water at a weight ratio of 1:1, soaking and then filtering.

[0013] (4) Fermentation and maturation: Place the sealed material in a fermentation environment at 35-40℃ and ferment for 30-120 days. During the fermentation process, turn the material over every 20-30 days and reseal it after turning to promote the uniform growth and metabolism of microorganisms. After fermentation, the cellar mud will be soft and loose, and can then be used for the brewing of Jiuliangxiang-type Baijiu.

[0014] The present invention also provides artificial pit mud obtained by the above preparation method, which has a large specific surface area and pore volume, with a specific surface area ≥48m² / g and a total pore volume ≥0.10cm³ / g, and significantly improved microbial richness and diversity.

[0015] This invention also provides the application of artificial cellar mud in the brewing of nine-grain aroma baijiu. Specifically, the artificial cellar mud is used for lining the walls or bottom of the cellar. The thickness of the mud on the walls is controlled at 8-12cm, and the thickness of the mud on the bottom is controlled at 15-20cm. After spreading and smoothing evenly, the grains are added for fermentation. The moisture content of the mash entering the cellar is controlled at 50%-52%, and the temperature of the mash entering the cellar is controlled at 32-34℃. This cellar mud is mainly suitable for brewing nine-grain aroma baijiu using sorghum, rice, millet, corn, millet, peas, wheat, mung beans, and glutinous rice as raw materials.

[0016] This invention utilizes the synergistic function of loess, mixed attapulgite clay, and diatomaceous earth to construct a cellar mud matrix with a multi-level porous structure and composite properties. Loess provides the basic framework; the mixed attapulgite clay constructs nanoscale pores, endowing the matrix with strong adsorption, slow-release nutrient function, and pH buffering capacity, stabilizing the supply of microorganisms and resisting fluctuations in fermentation acidity; diatomaceous earth contributes high porosity and a large specific surface area, significantly expanding the space for microbial attachment and enhancing the overall permeability and resistance to compaction and collapse of the cellar mud. The three elements work synergistically to form a multi-level interconnected pore system, providing diverse microenvironments for the rapid colonization and spatial differentiation of functional microorganisms, promoting the construction of a stable symbiotic network, and achieving a sustained and balanced supply of nutrients and maintenance of microenvironmental homeostasis. Ultimately, this significantly shortens the "cellar conditioning" time of new cellar mud, continuously supports the growth of highly efficient aroma-producing microorganisms, and improves the yield and quality of Jiuliang-style baijiu.

[0017] Compared with the prior art, the present invention has the following significant advantages: (1) Key performance is comprehensively improved: pH value, water content, loss on ignition, ammonium nitrogen, available P, available K and other key indicators are comprehensively improved compared with traditional loess pit mud, which is more conducive to microbial growth; the pit mud is soft and loose, with increased specific surface area and pore volume, which can effectively resist hardening and compaction.

[0018] (2) The micro-ecosystem is more complete: the richness and diversity of microorganisms in the pit mud have been significantly improved. It not only includes known functional microorganisms, but also contains a large number of unknown functional strains, forming a stable symbiotic network, which provides a guarantee for the generation of aroma substances.

[0019] (3) More prominent aroma production capacity: The content of core aroma components such as ethyl hexanoate is significantly increased in the nine-grain aroma type liquor brewed using the cellar mud of the present invention. The liquor has a rich aroma and mellow taste, which is comparable to the aroma production level of cellar mud aged for 3 years.

[0020] (4) Significantly improved alcohol yield and premium alcohol yield: Using the cellar mud of this invention for brewing, the alcohol yield can reach more than 36% and the premium alcohol yield exceeds 80%. Compared with traditional loess artificial cellar mud, the alcohol yield is increased by more than 6% and the premium alcohol yield is increased by more than 50%, significantly improving economic benefits. Attached Figure Description

[0021] Figure 1 Bar chart showing the relative distribution of microbial communities at the genus level in Example 1 and the control group (top 20 species in relative abundance) (a: fungi; b: bacteria) (fermentation time: 60 days). Detailed Implementation

[0022] The invention will be further explained below with reference to specific embodiments.

[0023] Control group (loess cellar mud): 10 tons of loess, 400 kg of pea flour, 500 kg of vanilla-based medium-temperature koji, 10 kg of dipotassium hydrogen phosphate, 5 kg of sodium acetate, 5 kg of magnesium sulfate, and 5 kg of yeast extract were thoroughly mixed. Then, the prepared cellar mud liquid (1000 kg of yellow water, 500 kg of distilled spirits, 200 kg of alcohol, and 3300 kg of lees liquid) was slowly added in batches to the thoroughly mixed mixture. After repeated stirring, the mixture was sealed tightly with plastic and fermented at 35-40℃ for 60 days. The mixture was turned over once every 30 days of fermentation, and then resealed. The traditional loess artificial cellar mud was obtained after fermentation.

[0024] Example 1: (1) Preparation of composite matrix: Take 7.5 tons of loess, 1.5 tons of mixed attapulgite clay and 1 ton of diatomaceous earth, mix them in a mass ratio of 7.5:1.5:1, crush them and pass them through an 80-mesh sieve to form a composite matrix; (2) Mixing of auxiliary materials: Add 400kg of pea flour (4% of the mass of the composite matrix), 500kg of vanilla medium temperature koji (5% of the mass of the composite matrix), and 25kg of nutrient regulator (0.25% of the mass of the composite matrix, consisting of 10kg of dipotassium hydrogen phosphate, 5kg of sodium acetate, 5kg of magnesium sulfate, and 5kg of yeast extract) to the composite matrix and mix thoroughly. (3) Adding the cellar mud liquid: Add the cellar mud liquid (1000 kg of yellow water, 500 kg of wine tails, 200 kg of alcohol, and 3300 kg of lees liquid in a mass ratio of 10:5:2:33) in 3 batches, with 1667 kg added in each batch. Stir for 15 minutes after each batch is added, and seal with plastic film after mixing evenly. (4) Fermentation and maturation: Place in an environment of 35-40℃ for 60 days to ferment. Turn it over once every 30 days of fermentation. After turning it over, reseal it. The artificial pit mud is obtained after the fermentation is completed.

[0025] Example 2: (1) Preparation of composite matrix: Take 7 tons of loess, 2 tons of mixed attapulgite clay and 1 ton of diatomaceous earth, mix them in a mass ratio of 7:2:1, crush them and pass them through an 80-mesh sieve to form a composite matrix; (2) Mixing of auxiliary materials: Add 600 kg of pea flour (6% of the mass of the composite matrix), 600 kg of vanilla medium temperature koji (6% of the mass of the composite matrix), and 30 kg of nutrient regulator (0.3% of the mass of the composite matrix, consisting of 12 kg of dipotassium hydrogen phosphate, 6 kg of sodium acetate, 6 kg of magnesium sulfate, and 6 kg of yeast extract) to the composite matrix and mix thoroughly. (3) Adding the cellar mud liquid: Add the cellar mud liquid (800 kg of yellow water, 600 kg of wine tails, 200 kg of alcohol, and 3220 kg of lees liquid in a mass ratio of 8:6:2:32.2) in 4 batches, with 1205 kg added in each batch. Stir for 12 minutes after each batch is added, and seal with plastic film after mixing evenly. (4) Fermentation and maturation: Place in an environment of 35-40℃ for 90 days for fermentation. Turn it over once on the 30th day and once on the 60th day of fermentation. After turning it over, reseal it. The artificial pit mud is obtained after the fermentation is completed.

[0026] Example 3: (1) Preparation of composite matrix: Take 5 tons of loess, 3 tons of mixed attapulgite clay and 2 tons of diatomaceous earth, mix them in a mass ratio of 5:3:2, crush them and pass them through an 80-mesh sieve to form a composite matrix; (2) Mixing of auxiliary materials: Add 800 kg of pea flour (8% of the mass of the composite matrix), 800 kg of vanilla medium temperature koji (8% of the mass of the composite matrix), and 50 kg of nutrient regulator (0.5% of the mass of the composite matrix, consisting of 20 kg of dipotassium hydrogen phosphate, 10 kg of sodium acetate, 10 kg of magnesium sulfate, and 10 kg of yeast extract) to the composite matrix and mix thoroughly. (3) Adding the cellar mud liquid: Add the cellar mud liquid (1200kg of yellow water, 400kg of wine tails, 100kg of alcohol, and 3000kg of lees liquid in a mass ratio of 12:4:1:30) in 5 batches, with 940kg added in each batch. Stir for 20 minutes after each batch is added, and seal with plastic film after mixing evenly. (4) Fermentation and maturation: Place in an environment of 35-40℃ for 120 days to ferment. Turn it over once on the 30th, 60th and 90th day of fermentation. After turning it over, reseal it. The artificial pit mud is obtained after the fermentation is completed.

[0027] Effect verification The results of comparing Example 1 with the control group are as follows: 1. Structural properties of pit mud: The pit mud of Example 1 had a larger specific surface area and a richer pore volume than the control group (Table 1). The specific surface area of ​​the pit mud of Example 1 was ≥48 m² / g, and the total pore volume was ≥0.10 cm³ / g, which was significantly higher than that of the control group (specific surface area 34.47 m² / g, total pore volume 0.0869 cm³ / g). After the raw grain fermentation was completed, the bottom of the pit was compressed by the lees. The average sinking of Example 1 was 3.5 cm, while the average sinking of the control group was 5.2 cm, indicating that Example 1 had excellent structural stability.

[0028] 2. Microbial biodiversity: Example 1: The Chao1 index, shannon_entropy index, and OTU number of bacteria and fungi in the pit mud were significantly higher than those in the control group, indicating a significant increase in microbial richness and diversity. Furthermore, a large number of unknown functional strains were present, providing potential impetus for aroma production (Table 2). Figure 1 ).

[0029] 3. Physicochemical properties: After fermentation was completed in both Example 1 and the control group, the pit mud was added to the walls of the fermentation pit and then used for grain feeding and brewing. The physicochemical indicators before grain feeding are shown in Table 3. The overall physicochemical indicators of Example 1 were superior to those of the control group, indicating a more suitable environment for microbial growth.

[0030] Example 1 showed a pH of 5.81, within the suitable weakly acidic range for the growth of functional bacteria in the pit mud; the control group had a lower pH, exceeding the optimal growth range for caproic acid bacteria (5.5–6.5). Higher levels of available phosphorus, available potassium, ammonium nitrogen, humic substances, and loss on ignition constituted a more balanced and abundant nutrient supply system. Furthermore, the higher moisture content indicated sufficient porosity and channels within the pit mud, facilitating gas exchange (permeability) and nutrient transport, creating a physically sound living environment for microorganisms.

[0031] 4. Brewing effect: After 120 days of fermentation, the mash is removed from the fermentation pits, distilled, and the spirit is collected in stages for tasting. This process is used to verify the maturity of the pit mud and to compare the spirit with that from 3-year-old fermentation pits used in normal production in the workshop.

[0032] The yield and premium liquor rate are shown in Table 4. Example 1 achieved a yield of 36.64% and a premium liquor rate of 83.50%, both exceeding those of the control group and the 3-year-old fermentation pits. The produced liquor had an alcohol content ≥70% vol, ethyl hexanoate content ≥2.39 g / L, and total acid content ≤1.50 g / L. The liquor exhibited a rich aroma and mellow taste, with overall quality superior to the control group and the 3-year-old fermentation pits. In particular, the double-bottom section of the control group, due to continuous compression from the mash, resulted in excessively dense pit mud, significantly inhibiting microbial fermentation activity and leading to a significant decrease in ethyl hexanoate content.

Claims

1. A method for preparing artificial cellar mud to improve the yield of high-quality liquor in Jiuliangxiang-type Baijiu, characterized in that, Includes the following steps: (1) Mix loess, mixed attapulgite clay and diatomaceous earth in a mass ratio of (5-7.5):(1.5-3):(1-2) to form a composite matrix; (2) Add 3%-8% of vanilla medium-temperature koji, 3%-8% of pea flour, and 0.25%-0.5% of nutrient regulator to the composite matrix and mix well; (3) Add 40%-50% of the composite matrix mass of pit mud liquid in batches, mix and seal; (4) Ferment at 35-40℃ for 30-180 days to obtain artificial pit mud.

2. The preparation method according to claim 1, characterized in that, In step (1), the particle size of the composite matrix is ​​not less than 80 mesh.

3. The preparation method according to claim 1, characterized in that: In step (2), the vanilla content in the vanilla koji is ≥10%; the nutrient regulator is composed of dipotassium hydrogen phosphate, sodium acetate, magnesium sulfate and yeast extract in a mass ratio of 2:1:1:

1.

4. The preparation method according to claim 1, characterized in that: In step (3), the cellar mud liquid is composed of yellow water, wine tails, edible alcohol and lees liquid in a mass ratio of (5-10):(4-8):(1-3):(30-35).

5. The preparation method according to claim 1, characterized in that: In step (3), the slurry is added in 3-5 batches, and stirred for 10-20 minutes after each batch is added.

6. The preparation method according to claim 1, characterized in that: In step (4), the fermentation process is carried out in a sealed manner, and the mixture is turned over every 20-30 days and then resealed.

7. An artificial pit mud prepared by any one of claims 1-6.

8. The application of the artificial cellar mud according to claim 7 in the brewing of Jiuliangxiang-type Baijiu.

9. The application according to claim 8, characterized in that: The artificial pit mud is used for lining the walls and bottom of the pit, with a wall thickness of 8-12cm and a bottom thickness of 15-20cm.

10. The application according to claim 8, characterized in that: The raw grains used in the nine-grain aroma-type baijiu include sorghum, rice, corn, millet, glutinous rice, peas, wheat, mung beans, and glutinous rice.

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