A method for making high-quality artificial pit mud based on modified mixed attapulgite clay for inhibiting nutrient salt migration
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- LANZHOU INSTITUTE OF CHEMICAL PHYSICS CHINESE ACADEMY OF SCIENCES
- Filing Date
- 2026-02-11
- Publication Date
- 2026-06-05
Smart Images
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of liquor brewing technology, specifically relating to a method for producing high-quality artificial cellar mud based on modified mixed attapulgite clay to inhibit nutrient migration. Background Technology
[0002] Cellar mud is one of the most crucial fermentation media in the brewing process of Jiuliangxiang-style baijiu, and its quality directly determines the flavor and quality of the baijiu. The microbial community within it is essential for producing the unique flavor of baijiu (especially aroma compounds such as ethyl hexanoate). Providing these microorganisms with sufficient nitrogen and phosphorus sources and other nutrients is a prerequisite for their normal growth and metabolism. Therefore, a balanced and sustained supply of nutrients is key to maintaining the stability of the cellar mud's microecology, preventing functional degradation, and enhancing the flavor of the original baijiu.
[0003] Nutrients in the cellar mud, such as sodium acetate (providing carbon), ammonium salts (such as ammonium bicarbonate and ammonium acetate) (providing nitrogen), phosphates (such as potassium dihydrogen phosphate and diammonium hydrogen phosphate) (providing phosphorus), and magnesium sulfate (a key trace element and enzyme activator), are the building blocks for the survival and reproduction of the functional microbial community. They provide the microbial community with the basic elements such as carbon, nitrogen, phosphorus, and sulfur necessary for cell synthesis and genetic material replication, and drive its vigorous energy metabolism. More importantly, nutrients are also indispensable precursors and catalysts for the synthesis of the main aroma substances in baijiu (such as ethyl hexanoate), directly determining the aroma-producing capacity of the cellar mud and the quality of the cellar aroma of baijiu.
[0004] Traditional pit mud preparation has long relied on loess as the core matrix and the direct addition of nutrients to maintain the activity of functional microorganisms. However, this method has significant drawbacks: First, loess itself is dense and has an underdeveloped pore structure, which limits the attachment space and colonization scale of microorganisms, making it difficult to build a rich and stable micro-ecosystem, thus restricting the diversity and metabolic activity of the functional microbial community. Second, the directly added nutrients are easily migrated and lost during pit mud mixing or loess leaching, resulting in uneven nutrient distribution, a lack of continuous supply, and even local pH fluctuations, which in turn interfere with the normal metabolism of microorganisms and affect the stable performance of their aroma-producing properties. Summary of the Invention
[0005] The purpose of this invention is to overcome the shortcomings of traditional loess cellar mud in existing technologies, such as a simple matrix structure, limited micro-ecological environment, unstable nutrient supply, and easy fluctuation of the micro-environment. This invention provides a method for producing high-quality artificial cellar mud based on modified attapulgite clay to inhibit nutrient migration. This method achieves stable nutrient loading on the attapulgite clay through mechanochemical modification. Combining the advantages of the composite matrix of modified clay and loess, it constructs a cellar mud micro-ecological environment with continuous nutrient supply and stable structure, significantly improving the quality and stability of the artificial cellar mud, thereby improving the flavor and quality of baijiu (Chinese liquor).
[0006] To achieve the above objectives, the present invention adopts the following technical solution: This invention uses nutrient salts as a modifier to pretreat mixed attapulgite clay using a mechanochemical method. This achieves efficient loading and stable fixation of nutrient components on the mineral surface and in the pores, inhibiting their ineffective migration and loss during fermentation and in the fermentation pit environment, thus achieving a stable and slow-release supply of nutrients to microorganisms. Based on this, the modified mixed attapulgite clay nanoporous structure is effectively embedded into the loess framework. The two are combined to construct a novel pit mud matrix, improving the matrix's porosity and microbial habitat. Combined with vanilla medium-temperature koji, pea flour, yeast extract, and pit mud liquid, this provides a structurally stable and nutritionally continuous new habitat for the microbial community, constructing a high-performance, highly stable artificial pit mud to improve the quality of baijiu (Chinese liquor). The specific steps include: (1) Preparation of nutrient-loaded modified mixed attapulgite clay: Mixed attapulgite clay with nutrients is placed in a planetary ball mill and modified under mechanochemical effects. After ball milling, the material is removed to obtain the modified mixed attapulgite clay loaded with nutrients. The nutrient salt is composed of at least three of the following: dipotassium hydrogen phosphate, potassium dihydrogen phosphate, diammonium hydrogen phosphate, ammonium bicarbonate, ammonium acetate, ammonium chloride, ammonium sulfate, ammonium phosphate, ammonium acetate, sodium acetate, and magnesium sulfate; the addition amount is 0.5% to 5% of the mass of the mixed attapulgite clay; the ball milling process parameters are: ball-to-material ratio 10:1 to 40:1, rotation speed 300 to 700 rpm, and time 0.5 to 2 hours; (2) Preparation of pit mud matrix: The modified attapulgite clay obtained in step (1) is mixed with the treated loess in a certain mass ratio to form pit mud matrix; wherein the modified attapulgite clay accounts for 5%-50% of the total mass of pit mud matrix; (3) Preparation of artificial pit mud: Add 3%–8% of vanilla medium-temperature koji, 3%–8% of pea flour, and 0.025%–0.25% of yeast paste by weight to the pit mud substrate obtained in step (2), mix and stir evenly; then slowly add pit mud liquid accounting for 30%–50% of the pit mud substrate by weight in batches, mix repeatedly, seal the mixture, and ferment and mature at 35–40℃ for 30–120 days to obtain the high-quality artificial pit mud. The mixed attapulgite clay mentioned in step (1) is crushed and sieved through an 80-mesh sieve before use, and has a moisture content of ≤30%.
[0007] The loess mentioned in step (2) is crushed and sieved through an 80-mesh sieve before use.
[0008] The cellar mud liquid in step (3) consists of yellow water, wine tails, edible alcohol, and lees liquid, with a weight ratio of (5-15): (4-8): (1-3): (30-35); wherein the alcohol content of the wine tails is 2-10% vol, and the lees liquid is the liquid obtained by mixing the wine lees (discarded lees) after distillation in the production of baijiu with water at a weight ratio of 1:1, soaking, and then filtering.
[0009] The vanilla-based medium-temperature koji contains no less than 10% vanilla. Vanilla-based medium-temperature koji is produced by adding vanilla raw materials to the raw material crushing or mixing process in the traditional medium-temperature koji preparation process, and then cultivating it at a medium temperature (maximum temperature 50-60℃). The finished koji block contains vanilla components (on a dry basis) of no less than 10%. The vanilla raw material is vanilla beans.
[0010] This cellar mud is mainly suitable for the fermentation of raw grains in strong-aroma baijiu, especially for the brewing of nine-grain aroma baijiu made from sorghum, rice, glutinous rice, peas, wheat, mung beans, glutinous rice, corn, and millet.
[0011] Compared with the prior art, the present invention has the following advantages: (1) By using mechanical force, nutrients are embedded into the pores and surface active sites of the mixed attapulgite clay, thus achieving stable fixation of nutrients and effectively inhibiting their migration and loss during the cultivation and use of pit mud. The fixed nutrients can be slowly released with the metabolism of microorganisms, providing a continuous and balanced supply of nutrients to the microbial community, avoiding unstable nutrient supply, local nutrient excess or deficiency, and maintaining the stability of the pit mud micro-ecology.
[0012] (2) Modified mixed attapulgite clay and loess are combined to construct a cellar mud matrix, which effectively improves the defects of loess matrix structure and limited micro-ecological environment, and promotes microbial colonization and community diversity. Experiments show that the cellar mud using the matrix of this invention has a microbial OTU number that is more than 25% higher than that of traditional loess cellar mud.
[0013] (3) Stabilize the pH value of the pit mud in a suitable range of 5.5-6.5 to avoid the inhibition of functional microbial activity by pH fluctuations; the test results showed that the pH fluctuation range during fermentation was ≤0.35, which was much lower than the 1.01 of traditional pit mud.
[0014] (4) The artificial cellar mud prepared by the present invention has stable function and can significantly improve the aroma production capacity of the cellar mud, especially the content of core aroma substances such as ethyl hexanoate; production experiments show that the baijiu brewed using the cellar mud of the present invention can achieve a high-quality baijiu rate of over 80%, and the total ester content of the double-distilled base liquor is as high as 13g / L or more, which meets the standards of premium baijiu. Attached Figure Description
[0015] Figure 1Bar 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
[0016] The invention will be further explained below with reference to specific embodiments.
[0017] The pretreatment of loess and mixed attapulgite clay used in the examples is as follows: Before use, the mixed attapulgite clay should be crushed, passed through an 80-mesh sieve, and have a moisture content of ≤30%.
[0018] The loess is crushed and sieved through an 80-mesh screen before use.
[0019] Control group (loess cellar mud): 10 tons of loess, 400 kg of pea flour, 500 kg of vanilla medium-temperature koji, 10 kg of dipotassium hydrogen phosphate, 5 kg of sodium acetate, 5 kg of magnesium sulfate, and 5 kg of yeast paste were thoroughly mixed. The prepared cellar mud liquid (1000 kg of yellow water, 500 kg of distilled liquor, 200 kg of alcohol, and 3300 kg of lees liquid) was slowly added to the well-mixed mixture in 6 batches. After repeated stirring, the mixture was sealed tightly with plastic and fermented at 35-40℃ for 60 days.
[0020] Example 1 (1) Modification of mixed attapulgite clay: 2.5 tons of mixed attapulgite clay and grinding balls were placed in a ball mill jar with a ball-to-material ratio of 20:1. 10 kg of dipotassium hydrogen phosphate, 5 kg of sodium acetate and 5 kg of magnesium sulfate were added. After sealing, the mixture was placed on a ball mill for ball milling. The ball milling speed was 400 rpm and the ball milling time was 2 hours. After the ball milling was completed, the material was taken out to obtain modified mixed attapulgite clay.
[0021] (2) Preparation of artificial cellar mud: 7.5 tons of loess and 2.5 tons of modified mixed attapulgite clay are thoroughly mixed to form cellar mud matrix; 400 kg of soybean flour, 500 kg of vanilla medium-temperature koji and 5 kg of yeast paste are added and thoroughly mixed evenly. The prepared cellar mud liquid (1000 kg of yellow water, 500 kg of wine tails, 200 kg of alcohol and 3300 kg of lees liquid) is added to the well mixed mixture in 6 batches. After repeated stirring, the mixture is sealed tightly with plastic and fermented at 35-40℃ for 60 days.
[0022] Example 2 (1) Modification of mixed attapulgite clay: 2.5 tons of mixed attapulgite clay and grinding balls were placed in a ball mill jar with a ball-to-material ratio of 20:1. 20 kg of dipotassium hydrogen phosphate, 10 kg of ammonium sulfate and 10 kg of sodium acetate were added accordingly. After sealing, the mixture was placed on a ball mill for ball milling. The ball milling speed was 400 rpm and the ball milling time was 1 hour. After the ball milling was completed, the material was taken out to obtain modified mixed attapulgite clay.
[0023] (2) Preparation of artificial pit mud 8.75 tons of loess and 1.25 tons of modified mixed attapulgite clay were mixed to form a cellar mud substrate. 500 kg of pea flour, 600 kg of vanilla medium-temperature koji, and 10 kg of yeast paste were added and thoroughly mixed. The prepared cellar mud liquid (800 kg of yellow water, 600 kg of distilled liquor, 100 kg of alcohol, and 3200 kg of lees liquid) was slowly added to the thoroughly mixed mixture in 4 batches. After being repeatedly stirred evenly with a machine, the mixture was sealed tightly with plastic and fermented at 35-40℃ for 120 days.
[0024] Example 3 (1) Modification of mixed attapulgite clay: 4 tons of mixed attapulgite clay and grinding balls were placed in a ball mill jar with a ball-to-material ratio of 40:1. 50 kg of potassium dihydrogen phosphate, 20 kg of sodium acetate, 12.5 kg of ammonium sulfate and 2.5 kg of magnesium sulfate were added accordingly. After sealing, the mixture was placed on a ball mill for ball milling. The ball milling speed was 400 rpm and the ball milling time was 2 hours. After the ball milling was completed, the material was taken out to obtain modified mixed attapulgite clay.
[0025] (2) Preparation of artificial cellar mud: 6 tons of loess, 4 tons of modified mixed attapulgite clay, 600 kg of pea flour, 700 kg of vanilla medium-temperature koji, and 5 kg of yeast paste are thoroughly mixed. The prepared cellar mud liquid (1200 kg of yellow water, 400 kg of wine tails, 100 kg of alcohol, and 3000 kg of lees liquid) is slowly added to the well-mixed mixture in 5 batches. After being repeatedly stirred evenly by machine, the mixture is sealed tightly with plastic and fermented at 35-40℃ for 90 days.
[0026] Effect verification The mud from Example 1 and the control group was applied to the walls of the fermentation pits. The mud layer on the pit walls was approximately 8-12 cm thick; the mud layer on the bottom was approximately 15-20 cm thick. After evenly smoothing, the grains were added for fermentation. The moisture content of the mash entering the pit was 50%-52%, and the temperature was 32-34℃. After 120 days of fermentation, the mash was removed from the pits, distilled, and the spirits were collected in stages for tasting. Meanwhile, a 3-year-old fermentation pit used in normal production in the workshop was used as a control pit.
[0027] 1. Microbial biodiversity: According to Table 1 and Figure 1As shown, the pit mud of Example 1 is significantly superior to the control group in terms of bacterial and fungal community diversity. Specifically, the Chao1 index, Shannon index, and OTU number are increased, indicating a significant improvement in its microbial richness and diversity. Simultaneously, the community contains a large number of genera whose functions are not yet fully understood, which may provide new potential resources for further enhancing aroma production capabilities.
[0028] 2. 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 better than those of the control group, indicating a more suitable environment for microbial growth.
[0029] Example 1 had a pH of 5.73, which is 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). The higher moisture content, available phosphorus, available potassium, ammonium nitrogen, humic substances, and loss on ignition compared to the control group constituted a more balanced and abundant nutrient supply system, creating a favorable living space for microbial growth.
[0030] 3. 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 fermentation pit mud and to compare the spirit with that from 3-year-old fermentation pits used in normal production in the workshop.
[0031] The yield and premium liquor rate are shown in Table 3. In Example 1, the yield and premium liquor rate not only surpassed those of mature 3-year-old cellars, but the premium liquor rate was also significantly better than the control group. This indicates that the process has approached or even partially surpassed the level of traditional aged cellars in terms of core product quality indicators.
[0032] Note: The quality grade of the raw spirit is based on Q / BHJTJS01-2025 "Nine Grains Stacking Process". The sensory evaluation results are shown in Table 4. In the example group, except for the upper and middle layer samples which were inferior to those from the mature 3-year-old cellars, the lower layer and the bottom layer of the double-distillation batches were superior to the control group and the 3-year-old cellars.
[0033] Compared with the control group and the 3-year-old fermentation pits, the raw liquor produced in Example 1 showed superior performance in key indicators (Table 5), exhibiting significant characteristics such as "higher alcohol content, outstanding total ester advantage in the double-distillation batch, and a generally higher and more stable ethyl hexanoate content." The fermentation pit mud in Example 1 possessed superior fermentation and aroma-producing properties. Its double-distillation batch liquor met the standards for premium-grade liquor in terms of sensory evaluation, total ester content, and ethyl hexanoate content.
[0034]
Claims
1. A method for preparing high-quality artificial pit mud based on modified attapulgite clay to inhibit nutrient migration, characterized in that, Includes the following steps: (1) Preparation of modified mixed attapulgite clay loaded with nutrients: Mixed attapulgite clay with nutrients and placed in a planetary ball mill for modification under mechanochemical effect; After ball milling, the material is taken out to obtain the modified mixed attapulgite clay loaded with nutrients. The nutrient salt is composed of at least three of the following: dipotassium hydrogen phosphate, potassium dihydrogen phosphate, diammonium hydrogen phosphate, ammonium bicarbonate, ammonium acetate, ammonium chloride, ammonium sulfate, ammonium phosphate, ammonium acetate, sodium acetate, and magnesium sulfate, and the addition amount is 0.5% to 5% of the mass of the mixed attapulgite clay; the ball milling process parameters are: ball-to-material ratio 10:1 to 40:1, rotation speed 300 to 700 rpm, and time 0.5 to 2 hours; (2) Preparation of pit mud matrix: The modified attapulgite clay obtained in step (1) is mixed with the treated loess to form pit mud matrix; wherein the modified attapulgite clay accounts for 5%-50% of the total mass of the pit mud matrix; (3) Preparation of artificial cellar mud: Add 3% to 8% of the mass of vanilla medium-temperature koji, 3% to 8% of the mass of pea flour and 0.025% to 0.25% of the mass of yeast paste to the cellar mud matrix obtained in step (2), mix and stir evenly; then slowly add 30% to 50% of the mass of cellar mud liquid to the cellar mud matrix in batches, mix repeatedly, seal the mixture, and ferment and mature at 35 to 40°C for 30 to 120 days to obtain artificial cellar mud.
2. The method according to claim 1, characterized in that, The mixed attapulgite clay mentioned in step (1) is crushed and sieved through an 80-mesh sieve before use, and has a moisture content of ≤30%.
3. The method according to claim 1, characterized in that, The loess described in step (2) is crushed and sieved through an 80-mesh sieve before use.
4. The method according to claim 1, characterized in that, The cellar mud liquid mentioned in step (3) consists of yellow water, wine tails, alcohol and lees liquid, with a weight ratio of (5-10): (4-8): (1-3): (30-35).
5. The method according to claim 1, characterized in that, The vanilla content in the vanilla koji in step (3) shall not be less than 10%.
6. The method according to claim 1, characterized in that: The artificial cellar mud is suitable for brewing nine-grain aroma-type baijiu made from sorghum, rice, glutinous rice, peas, wheat, mung beans, glutinous rice, corn, and glutinous rice.