Method for rapidly judging property change of pit sealing mud

Abstract

The invention relates to a method for quickly judging the property change of pit sealing mud in the technical field of white spirit brewing, which comprises the following steps: S1, sample collection: collecting pit sealing mud samples before different rounds of pit opening in Maotai-flavor white spirit brewing; s2, index detection: carrying out soil shear strength and pH value detection on the collected sample; measuring the soil organic matter content by adopting an ignition loss method; determining the available nitrogen content of the soil by adopting an alkaline hydrolysis diffusion method; determining the total potassium content of the soil by adopting a sodium hydroxide melting-flame photometer method; the total phosphorus in the soil is determined by adopting a sodium hydroxide alkali fusion-molybdenum antimony anti-spectrophotometric method; s3, quality evaluation: setting a quality evaluation threshold value of the pit sealing mud, and judging that the pit sealing mud is qualified when the shear strength of the pit sealing mud is greater than or equal to 25kPa and the pH is 6.0-6.8; when the shear strength is less than 25kPa or the pH value is less than 6.0, the product is judged to be unqualified; and when the shear strength is less than 18kPa and the pH value is less than 5.9, the complete failure is judged. According to the scheme, the problem that existing cellar sealing mud quality evaluation cannot meet the real-time monitoring requirement in actual production is solved.

Description

Technical Field

[0001] This invention relates to the field of baijiu brewing technology, specifically to a method for rapidly determining changes in the properties of sealing mud. Background Technology

[0002] The brewing process of Maotai-flavor liquor is complex, and sealing the fermentation pits is a crucial technical step. The sealing mud, as the core sealing material, provides a sealed, anaerobic environment for the fermentation mash, regulating the types and quantities of brewing microorganisms and directly affecting the formation of ethanol and flavor compounds. Currently, the sealing mud for Maotai-flavor liquor fermentation pits is mainly made from locally unique purplish-red clay. This resource is non-renewable, and with the development of the industry, demand is increasing daily, making resource scarcity a more prominent issue.

[0003] According to relevant requirements in Guizhou Province, the recycling rate of sealing mud should reach 50%. However, in actual production, due to technological limitations, improper production methods, and inadequate management, the recycling rate is generally low. One Maotai-flavor liquor company's average recycling rate is only 18.9%, with a maximum of only 35.22%, far below the required level. During recycling, sealing mud is prone to problems such as decreased adhesion, poor sealing, and cracking / collapse. Furthermore, excessive husk content and bacterial invasion / molding can lead to unstable microbial composition, affecting the quality of the liquor product. Ultimately, this results in the disposal of the sealing mud, causing resource waste and the risk of non-point source pollution in the Chishui River basin.

[0004] Current technologies for assessing the quality of sealing mud primarily focus on its impact on microbial composition and flavor compounds, lacking systematic research from a soil science perspective. Furthermore, the assessment methods are complex, time-consuming, and cannot achieve rapid, real-time monitoring. Some studies focus on indicators such as pH, available phosphorus, and moisture content of the sealing mud, but fail to define core evaluation indicators and thresholds, resulting in insufficient accuracy and difficulty in guiding the recycling and maintenance of sealing mud in actual production. Therefore, developing a simple, rapid, and accurate method for assessing the quality of sealing mud is of great significance for improving the recycling rate of sealing mud, reducing resource waste, and ensuring the stability of baijiu quality. Summary of the Invention

[0005] The present invention aims to provide a method for rapidly determining changes in the properties of sealing mud, in order to solve the problems that existing methods for assessing the quality of sealing mud are complex, time-consuming, and lack accuracy, and cannot meet the real-time monitoring needs in actual production.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a method for rapidly determining changes in the properties of sealing mud, comprising the following steps: S1, Sample collection: Before opening the cellar in different rounds of brewing sauce-flavored baijiu, the original sample of the sealing mud was collected using a ring cutter, and unused purple-red mud was collected as a control sample. S2, Index Testing: Soil shear strength and pH value were tested on the collected sealing mud samples. For pH value determination, the soil sample was mixed with ultrapure water at a ratio of 1:2.5, shaken, and allowed to stand for 1-3 hours. The supernatant was then measured using a pH meter. Soil organic matter content was determined using the loss on ignition method. Soil available nitrogen content was determined using the alkaline diffusion method. Soil total potassium content was determined using the sodium hydroxide fusion-flame photometry method. Soil total phosphorus content was determined using the sodium hydroxide alkaline fusion-molybdenum antimony spectrophotometric method. S3, Quality Assessment: Set quality assessment thresholds for the sealing mud. When the shear strength of the sealing mud is ≥25kPa and the pH value is between 6.0 and 6.8, it is considered qualified and can continue to be recycled. When the shear strength is <25kPa or the pH value is <6.0, it is considered unqualified and requires maintenance treatment or replacement. When the shear strength is <18kPa and the pH value is <5.9, it is considered completely ineffective and its continued use is prohibited.

[0007] Preferably, as an improvement, the sample collection time in step S1 is as follows: the control sample is collected before the sand is added in September of the same year, and the sealing mud samples are collected in the following rounds: first round, mid-January of the following year; second round, mid-February of the following year; third round, mid-April of the following year; fourth round, mid-June of the following year; fifth round, mid-July of the following year; sixth round, mid-August of the following year; seventh round, mid-September of the following year; and before opening the pit.

[0008] Preferably, as an improvement, the sample collection in step S1 uses a volume of 100 cm³. 3 Soil samples of purplish-red clay and sealing mud were collected using a ring cutter, with each batch containing more than or equal to nine soil samples.

[0009] Preferably, as an improvement, in step S1, when collecting samples, more than or equal to 3 samples of sealing mud soil are collected from each pit. Then, the sealing mud samples collected in the same batch are mixed and collected using the quartering method. After the samples are freeze-dried, the soil samples are crushed using a multi-purpose pulverizer used in the experiment, passed through a 100-mesh sieve, and then placed in polyethylene self-sealing bags for low-temperature storage.

[0010] Preferably, as an improvement, in step S2, when testing the soil shear strength, the measuring head is inserted into the soil to a depth of 2-3 cm, and the rotation speed is controlled at 2-5 r / min to ensure the stability of the measurement data.

[0011] The beneficial effects of this plan are: 1. This scheme reveals the changes in properties such as bulk density, pH, shear strength, and organic matter content of the sealing mud during the brewing process of Maotai-flavor liquor from a soil science perspective. It proposes that soil shear strength and pH can be used as rapid detection indicators for problems such as decreased adhesion and poor sealing of the sealing mud. This can continuously monitor the applicability of the sealing mud and help improve the sealing mud production process.

[0012] 2. The core indicator measurement is simple to operate and takes little time (≤30 minutes). On-site testing causes little disturbance to the sealing performance of the sealing mud and can be completed on-site. This meets the needs of dynamic monitoring during multiple rounds of fermentation and avoids the quality risks caused by the lag of traditional methods.

[0013] 3. Through quality grading, the recycling rate of sealing mud can be increased to over 50%, which can reduce the consumption of purple-red mud by more than 30% annually, reduce the waste of non-renewable resources, and reduce environmental pollution caused by waste sealing mud.

[0014] 4. By promptly identifying ineffective sealing mud and optimizing the sealing effect, fluctuations in the fermentation environment are reduced, thereby decreasing the fluctuation range of key indicators such as total acidity of the base liquor by 40% and improving product quality consistency. Attached Figure Description

[0015] Figure 1 This is a graph showing the change in bulk density of the sealing mud soil during the brewing process of soy sauce-flavored liquor in an embodiment of the present invention.

[0016] Figure 2 This is a diagram showing the change in field water holding capacity of the sealing mud soil during the brewing process of Maotai-flavor liquor in an embodiment of the present invention.

[0017] Figure 3 This diagram illustrates the variation in shear strength of the sealing mud soil during the brewing process of Maotai-flavor liquor in this embodiment of the invention.

[0018] Figure 4 This is a graph showing the changes in pH value of the sealing mud soil during the brewing process of Maotai-flavor liquor in this embodiment of the invention (left Y-axis) and the changes in total acid content during the brewing process of Maotai-flavor liquor (right Y-axis).

[0019] Figure 5 This is a graph showing the changes in total organic matter (A), available nitrogen (B), total potassium (C), and total phosphorus (D) in the soil of the sealing cellar mud during the brewing process of Maotai-flavor liquor in this embodiment of the invention.

[0020] Figure 6 This is a correlation analysis diagram of the physicochemical properties of the sealing mud in an embodiment of the present invention. Detailed Implementation

[0021] The following detailed description illustrates the specific implementation method: Example A method for quickly determining changes in the properties of sealing mud includes the following steps: S1, Sample Collection: Before opening the fermentation pits at different stages of the brewing process of Maotai-flavor liquor, samples with a volume of 100 cm³ were collected. 3 Unused purplish-red mud samples were collected using a ring cutter, and unused mud samples were collected as a control. The control sample (CK) was collected before the sand was added in September. The mud samples were collected in the following rounds: first round, mid-January of the following year (1st); second round, mid-February of the following year (2nd); third round, mid-April of the following year (3rd); fourth round, mid-June of the following year (4th); fifth round, mid-July of the following year (5th); sixth round, mid-August of the following year (6th); and seventh round, mid-September of the following year (7th). Samples were collected before opening the pits. At least nine soil samples were collected from each batch, and at least three mud samples were collected from each pit. The mud samples from the same batch were then mixed and collected using the quartering method. After freeze-drying, the soil samples were pulverized using a multi-purpose pulverizer, passed through a 100-mesh sieve, and stored in polyethylene self-sealing bags at 4°C.

[0022] S2, Index Testing: Soil shear strength and pH value were tested on the collected sealing mud samples. Soil shear strength was determined by vertically inserting a soil shear tester into the soil surface and rotating it at a constant speed until shear failure occurred, then reading the scale data. pH value was determined by mixing soil sample with ultrapure water at a ratio of 1:2.5, shaking, allowing it to stand for 1-3 hours, and then measuring the supernatant with a pH meter. Soil organic matter content was determined using the loss on ignition method. Available nitrogen content was determined using the alkaline diffusion method. Total potassium content was determined using the sodium hydroxide fusion-flame photometry method. Total phosphorus content was determined using the sodium hydroxide alkaline fusion-molybdenum antimony spectrophotometric method. S3, Quality Assessment: Set quality assessment thresholds for the sealing mud. When the shear strength of the sealing mud is ≥25kPa and the pH value is between 6.0 and 6.8, it is considered qualified and can continue to be recycled. When the shear strength is <25kPa or the pH value is <6.0, it is considered unqualified and requires maintenance treatment or replacement. When the shear strength is <18kPa and the pH value is <5.9, it is considered completely ineffective and its continued use is prohibited.

[0023] Analysis of experimental results: (1) Changes in soil bulk density, porosity and field water holding capacity Soil bulk density is an important indicator of soil compaction, closely related to parent rock, local climate, and organic matter content, and greatly affected by human factors. Soil porosity is the percentage of soil pore volume to total soil volume, and is generally not measured directly but calculated by dividing soil bulk density by specific gravity. A well-designed soil pore system provides a sealed environment for fermenting mash while promoting the exchange of substances at the soil-air interface and the formation of flavor compounds. Research results are as follows... Figure 1 As shown, the bulk density of the purplish-red clay before its use as sealing mud was 1.75 g / cm³. 3 The soil structure is relatively compact. The bulk density of the sealing mud varies from 1.75 to 2.03 g / cm³ during use. 3 The average bulk density is 1.88 ± 0.11 g / cm³. 3 As the fermentation cycles increased, the differences in soil bulk density of the sealing mud from each cycle became increasingly apparent, exhibiting a parabolic upward trend. In particular, the seventh-cycle sealing mud showed a significantly higher bulk density than the control group (CK group, p < 0.05), reaching 1.16 times the bulk density of the original purple-red mud. This increase in bulk density led to a decrease in soil porosity. Measurements showed that soil porosity varied from 20.70% to 31.51%, with an average porosity of 27.34 ± 4.16%. These changes may be related to the processing techniques involved in removing, stirring, and compacting the sealing mud during each fermentation cycle, which prevented it from maintaining its original soil structure and continuously damaged the internal capillaries, resulting in decreased porosity and a continuously increasing bulk density. Observations showed that the trend of field water holding capacity was opposite to that of soil bulk density; that is, with the increasing number of cycles of sealing mud use, field water holding capacity showed a decreasing trend (see...). Figure 2 The field water holding capacity of the sealing mud varied from 24.34% to 21.07%, with an average value of 22.62 ± 0.21% during the production idle period, which was 0.92 times that of the control group. These results indicate that the increased bulk density and decreased field water holding capacity suggest that the sealing mud preparation process ensured relatively good sealing performance, but its water retention capacity was affected, making it prone to water loss and cracking. This is the reason for the decreased structural integrity of the sealing mud. Therefore, in the later stages of the pit-keeping period, the sealing mud should be strengthened and kept moist to prevent cracking.

[0024] (2) Changes in soil shear strength Generally, soil shear strength is positively correlated with soil bulk density, but soil particle size, shape, and root distribution also affect soil shear strength. The research results contradict those of the soil under the aforementioned natural conditions; the shear strength of the sealing mud from each round of sealing is as follows: Figure 3As shown in the figure, the greater the shear strength of the sealing mud, the stronger its soil cohesion. During the pit-keeping period, the average shear strength of the sealing mud was 33.93±10.77 kPa, with the first round of sealing mud exhibiting the highest shear strength at 52.00 kPa. This is equivalent to 1.26 times that of the purplish-red mud (41.25±2.87 kPa, CK), significantly higher than the original shear strength of the purplish-red mud. This is because the sealing mud needs to be mixed and kneaded with water before its first use, which reduces soil porosity, makes soil particles more compact, and increases viscosity, thus maintaining good sealing performance. However, with the increase in the number of use rounds, the shear strength of the sealing mud showed a significant linear decreasing trend. By the final round, the shear strength of the sealing mud was only 0.44 times that of the purplish-red mud, and only 0.35 times that of the first round. These changes may be related to the intrusion of materials such as rice husks into the soil. Although the soil bulk density continued to increase during the use of the sealing mud, the entry of tiny intruders made the soil prone to cracking, resulting in a significant reduction in shear strength. Because soil shear strength measurement is simple and easy to perform, and the test results are intuitive and stable, the change in the shear strength of the sealing mud may become an important factor in evaluating the sealing performance of the sealing mud in production practice.

[0025] (3) Changes in pH value of sealing mud soil The purplish-red mud has a pH of 6.88±0.02, classifying it as neutral soil. During the anaerobic fermentation of soy sauce-flavored baijiu, the main acids produced are acetic acid and lactic acid. These acids migrate to the sealing mud, thus affecting its pH value. Figure 4 As shown, the pH of the sealing mud continuously decreased throughout the fermentation period, reaching 5.91±0.11 in the final batch, a significant decrease of 14.06% compared to the purple-red mud. Related studies indicate that the pH of the base liquor ranged from 3.515 to 3.767, and the total acid content of the base liquor across seven batches exhibited a single-peak curve, with the peak occurring in the second batch. The first and second batches were also the batches in which the mash produced the most acetic acid and lactic acid, and the pH of the sealing mud also showed a significant decrease in these two batches, subsequently stabilizing. However, by the seventh batch, the pH of the sealing mud decreased significantly again, indicating that the acid accumulated in the sealing mud reached or exceeded the soil buffering threshold, further acidifying the soil colloids. Furthermore, the pH changes in the sealing mud may also be related to the gleying process. In a consistently moist environment, the organic matter in the sealing mud decomposes, producing more reducing substances, thus acidifying the sealing mud soil.

[0026] (4) Changes in soil organic matter, available nitrogen, total potassium, and total phosphorus in the sealing mud like Figure 5As shown, the organic matter, available nitrogen, total potassium, and total phosphorus in the sealing mud soil all generally increased significantly with each fermentation cycle. Specifically, compared to the purple-red clay soil, the sealing mud soil showed an average increase of 24.46% in organic matter, 391.68% in available nitrogen, 16.81% in total potassium, and 2.54% in total phosphorus. This indicates that during the use of the sealing mud, a significant material exchange occurred between the soil and the fermentation mash. Microbial activity in the fermentation mash was intense, and the rate of microbial decomposition of organic matter in the mash accelerated further with each fermentation cycle. As the solid matter in the fermentation mash decreased, the content of soluble organic matter continuously increased, which promoted the migration of substances into the sealing mud, thus leading to an increase in the content of the aforementioned substances in the sealing mud. Moreover, the distillation process does not cause a large amount of the above-mentioned substances to migrate into the base liquor. The abundance of these substances in the mash continues to increase. For example, studies have shown that the extraction rate of protein from the mash of Maotai-flavor liquor can reach 25.76%, which is a high extraction rate. It also contains a rich variety of amino acids and small molecule peptides. The total potassium content of the mash is high (about 28.1 g / kg), and the total phosphorus content of sorghum seeds, which is the main component of the mash, is about 329 mg / kg. Both are higher than those of the purple-red mud soil. These factors further increase the concentration gradient of the above-mentioned substances in the mash relative to the sealing mud, which in turn increases the migration rate of the substances.

[0027] (5) Correlation between the physical and chemical properties of the sealing mud and soil like Figure 6 Correlation heatmaps show that among the soil physical properties of the sealing mud, soil bulk density and soil field water holding capacity (-0.84, p < 0.01) and soil shear strength (-0.83, p < 0.01) all exhibit highly significant negative correlations. Any one of these three can be used as a soil physical factor to measure the decline in the sealing performance of the sealing mud. To avoid significant damage to the sealing mud during the testing process, soil shear strength can be used as the measurement index. Soil shear strength data can be obtained quickly and can be continuously monitored during the use of the sealing mud, with minimal impact on the sealing performance. Among the soil chemical properties, soil pH shows highly significant negative correlations with soil organic matter (-0.94, p < 0.01), available nitrogen (-0.96, p < 0.01), total potassium (-0.82, p < 0.01), and total phosphorus (-0.76, p < 0.01). Given the simplicity and convenience of the soil pH testing method, soil pH can be used as the measurement index among the soil chemical indicators. In summary, considering the physical and chemical properties of the soil, soil shear strength and pH can be used as rapid detection indicators for the sealing performance of sealing mud during the brewing process of Maotai-flavor liquor. This allows for continuous monitoring of the suitability of sealing mud, significantly reducing the workload in the monitoring process and improving the effectiveness and efficiency of monitoring.

[0028] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for rapidly determining changes in the properties of sealing mud, characterized in that, Includes the following steps: S1, Sample collection: Before opening the cellar in different rounds of brewing sauce-flavored baijiu, the original sample of the sealing mud was collected using a ring cutter, and unused purple-red mud was collected as a control sample. S2, Index Testing: Soil shear strength and pH value were tested on the collected sealing mud samples. For pH value determination, the soil sample was mixed with ultrapure water at a ratio of 1:2.5, shaken, and allowed to stand for 1-3 hours. The supernatant was then measured using a pH meter. Soil organic matter content was determined using the loss on ignition method. Soil available nitrogen content was determined using the alkaline diffusion method. Soil total potassium content was determined using the sodium hydroxide fusion-flame photometry method. Soil total phosphorus content was determined using the sodium hydroxide alkaline fusion-molybdenum antimony spectrophotometric method. S3, Quality Assessment: Set quality assessment thresholds for the sealing mud. When the shear strength of the sealing mud is ≥25kPa and the pH value is between 6.0 and 6.8, it is considered qualified and can continue to be recycled. When the shear strength is <25kPa or the pH value is <6.0, it is considered unqualified and requires maintenance treatment or replacement. When the shear strength is <18kPa and the pH value is <5.9, it is considered completely ineffective and its continued use is prohibited.

2. The method for rapidly determining changes in the properties of sealing mud according to claim 1, characterized in that: The sample collection time in step S1 is as follows: the control sample is collected before the sand is added in September; the sealing mud samples are collected in the first round in mid-January of the following year; the second round in mid-February of the following year; the third round in mid-April of the following year; the fourth round in mid-June of the following year; the fifth round in mid-July of the following year; and the sixth round in mid-August of the following year. The seventh round will take place in mid-September of the following year. Collected before opening the cellar.

3. The method for rapidly determining changes in the properties of sealing mud according to claim 2, characterized in that: In step S1, a sample was collected using a volume of 100 cm³. 3 Soil samples of purplish-red clay and sealing mud were collected using a ring cutter, with each batch containing more than or equal to nine soil samples.

4. The method for rapidly determining changes in the properties of sealing mud according to claim 3, characterized in that: In step S1, when collecting samples, collect more than or equal to 3 samples of sealing mud soil from each pit. Then, mix the sealing mud samples collected in the same batch and collect the sealing mud samples using the quartering method. After the samples are freeze-dried, crush the soil samples using a multi-purpose pulverizer used in the experiment, pass them through a 100-mesh sieve, and then put them into polyethylene self-sealing bags for low-temperature storage.

5. The method for rapidly determining changes in the properties of sealing mud according to claim 4, characterized in that: In step S2, when testing the soil shear strength, the measuring head is inserted into the soil to a depth of 2-3 cm, and the rotation speed is controlled at 2-5 r / min to ensure the stability of the measurement data.

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