Soy sauce brewing method and soy sauce

Abstract

The invention provides a soy sauce brewing method and soy sauce, the soy sauce brewing method adopts an ancient-process koji making and an ancient-process jar fermentation brewing, innovatively combines a gradient ratio hyperbolic process, double fermentation and double sun-curing, does not need to additionally add materials such as an exogenous enzyme preparation and caramel color, belongs to single-strain koji making, and is simple in process, low in cost and easy to popularize. The koji making technology is relatively simple, long-period brewing is conducted in the natural environment, the Maillard reaction is more sufficient, and the produced ancient-method soy sauce is thicker in body, more fragrant and sweet in taste and richer in sauce fragrance.

Description

Technical Field

[0001] This application relates to the field of soy sauce brewing technology, and in particular to soy sauce brewing methods and soy sauce. Background Technology

[0002] Soy sauce is a traditional condiment with a long history, mainly made from soybeans and wheat through steaming, koji making, and fermentation. Its production and quality have always been a key research focus in the condiment industry. Traditionally brewed soy sauce is rich in flavor, mellow and fragrant, and has a long-lasting aftertaste.

[0003] Currently, the traditional brewing method for soy sauce has problems such as complex preparation process, need to add exogenous enzymes, and the resulting soy sauce has not a rich enough taste and aroma, which urgently need to be improved. Summary of the Invention

[0004] Based on this, this application provides a soy sauce brewing method and soy sauce with a relatively simple preparation process, no need to add exogenous enzymes, and a soy sauce with a rich taste and aroma.

[0005] The first aspect of this application provides a method for brewing soy sauce, comprising the following steps:

[0006] The first portion of cooked soybeans, the first portion of wheat flour, and the first portion of Aspergillus oryzae are mixed and then subjected to the first koji-making process to prepare the first koji material; the mass percentage of the first portion of cooked soybeans to the total mass of the first portion of cooked soybeans and the first portion of wheat flour is ≤30%;

[0007] The second part of cooked soybeans, the second part of wheat flour, and the second part of Aspergillus oryzae are mixed and then subjected to a second koji-making process to prepare the second koji material; the mass percentage of the second part of cooked soybeans to the total mass of the second part of cooked soybeans and the second part of wheat flour is ≥60%;

[0008] The first batch of starter culture is mixed with salt water and then fermented for the first time. On the 5th-10th day, the 15th-20th day, and after the fermentation is completed, fermented crude oil A1, fermented crude oil A2, and fermented crude oil A3 are extracted from the fermented mash. The fermented crude oil A1, the fermented crude oil A2, and the fermented crude oil A3 are combined to form combined crude oil B.

[0009] After the second koji material is mixed with a portion of the combined crude oil B, a second fermentation is carried out under sunlight, and during the fermentation period, crude oil is periodically extracted from the mash to irrigate the mash.

[0010] Oil is extracted from the fermented mash obtained after the second fermentation to obtain crude fermented mash.

[0011] The crude soy sauce mash is sun-dried in earthenware jars to obtain the soy sauce.

[0012] The fermented crude oil A1, fermented crude oil A2 and fermented crude oil A3 have the following mass percentages in the combined crude oil B: m1, m2 and m3, respectively, with 0 ≤ m1 ≤ 30%, 0 ≤ m2 ≤ 30%, and 40% ≤ m3 ≤ 100%.

[0013] In some embodiments, the combined crude oil B is added in stages during the second fermentation process.

[0014] In some embodiments, the total mass of the combined crude oil B added during the second fermentation process is 2.1 to 2.3 times the mass of the second koji material.

[0015] In some embodiments, the salinity of the combined crude oil B added during the second fermentation process is controlled to be 18°Bé-22°Bé. In some embodiments, the second fermentation time is ≥6 months, optionally 6-8 months.

[0016] In some embodiments, the sun-drying time is 30-60 days.

[0017] In some embodiments, the salt solution has a salt content of 18°Bé-22°Bé.

[0018] In some embodiments, the brine has a salt content of 18°Bé-22°Bé, and the mass of the brine is 2.1 to 2.3 times the mass of the first koji material.

[0019] In some embodiments, the temperature of the first fermentation is 20°C-40°C, and the time is 3-5 months.

[0020] In some embodiments, the temperature for the first fermentation is 30°C-40°C, and the time is 40-60 hours.

[0021] In some embodiments, the mass of the first portion of Aspergillus oryzae is 0.2%-0.7% of the total mass of the first portion of cooked soybeans and the first portion of wheat flour.

[0022] In some embodiments, the temperature for the second fermentation process is 30°C-40°C, and the time is 40-60 hours.

[0023] In some embodiments, the mass of the second part of Aspergillus oryzae is 0.2%-0.7% of the total mass of the second part of cooked soybeans and the second part of wheat flour.

[0024] The second aspect of this application provides a soy sauce, which is brewed using the soy sauce brewing method described above.

[0025] The above-mentioned soy sauce brewing method has at least the following beneficial effects:

[0026] (1) In this soy sauce brewing method, cooked soybeans and wheat flour with different raw material ratios are used to make koji, resulting in first koji material and second koji material used for the first fermentation and the second fermentation, respectively. The raw material for making the first koji material uses a high carbon source, which can significantly improve the activity of enzymes such as amylase and saccharifying enzyme; the raw material for making the second koji material uses a high nitrogen source, which can significantly improve the activity of protease and glutaminase. Thus, by adopting a gradient ratio double koji process, amylase, saccharifying enzyme, protease and glutaminase achieve complementary advantages, and the enzyme activity of the fermentation system is significantly improved.

[0027] (2) In this soy sauce brewing method, double sun-drying (sun-drying of the second fermentation mash and sun-drying of crude oil) and traditional earthenware jar slow brewing process are adopted. The Maillard reaction occurs fully under the sun, which improves the appearance and preservation of the traditional soy sauce. The content of key aroma substances such as 4-ethylguaiacol, HEMF and HDMF in the soy sauce is significantly increased, resulting in a rich aroma and obvious soy sauce flavor. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application and to more completely understand this application and its beneficial effects, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 A process flow diagram of a soy sauce brewing method provided in one embodiment. Detailed Implementation

[0030] To facilitate understanding of this application, a more complete description of the application will be provided below with reference to relevant embodiments. Preferred embodiments of the application are given below. However, the application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of this application.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0032] As used herein, the terms "and / or," "or / and," and "and / or" encompass any one of two or more of the related listed items, as well as any and all combinations of the related listed items. These arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. It should be noted that when at least three items are connected using at least two conjunctions selected from "and / or," "or / and," and "and / or," it should be understood that, in this application, the technical solution undoubtedly includes solutions connected by "logical AND," and also undoubtedly includes solutions connected by "logical OR."

[0033] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0034] In this application, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0035] This document only specifically discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form an unspecified range; and any lower limit can be combined with other lower limits to form an unspecified range, just as any upper limit can be combined with any other upper limit to form an unspecified range. Furthermore, each individually disclosed point or single value can itself serve as a lower or upper limit and be combined with any other point or single value or with other lower or upper limits to form an unspecified range.

[0036] Unless otherwise specified, the temperature parameters in this application may be either constant temperature processing or processing within a certain temperature range. The constant temperature processing allows temperature fluctuations within the precision range controlled by the instrument, such as ±5°C, ±4°C, ±3°C, ±2°C, or ±1°C.

[0037] In this document, the term "suitable" as used in phrases such as "suitable combination," "suitable method," and "any suitable method" refers to the ability to implement the technical solution of this application, solve the technical problem of this application, and achieve the expected technical effect of this application.

[0038] In this application, terms such as "further," "even further," and "particularly" are used to describe purposes and indicate differences in content, but should not be construed as limiting the scope of protection of this application.

[0039] In this application, "optionally," "optionally," and "optional" mean that something is optional, that is, it means that it is selected from either "with" or "without." If there are multiple "optional" entries in a technical solution, unless otherwise specified, and there are no contradictions or mutual constraints, each "optional" entry shall be independent.

[0040] In the description of the application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0041] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions. Unless otherwise specified, all technical features and optional technical features of this application can be combined to form new technical solutions.

[0042] Unless otherwise specified, all steps of this application may be performed sequentially or randomly, but sequentially is preferred.

[0043] Traditional brewing methods produce soy sauce with a rich, mellow, and savory flavor, and a lingering aftertaste. However, current methods for producing traditional soy sauce suffer from problems such as complex processes, the need to add exogenous enzymes, and a lack of intense flavor and aroma, all of which urgently require improvement.

[0044] To address the aforementioned issues, this application provides a soy sauce brewing method that employs traditional koji-making techniques and fermentation in traditional earthenware jars. It innovatively utilizes a gradient-ratio double-koji process, combining double fermentation and double sun-drying. This method eliminates the need for additional exogenous enzymes, caramel coloring, or other materials. Furthermore, it involves single-strain koji-making, resulting in a relatively simple process. The long-term brewing under natural conditions allows for a more complete Maillard reaction, producing a soy sauce with a richer body, sweeter taste, and more intense soy sauce aroma.

[0045] One or more embodiments of this application provide a soy sauce brewing method, comprising the following steps: mixing a first portion of cooked soybeans, a first portion of wheat flour, and a first portion of Aspergillus oryzae for a first koji-making process to prepare a first koji material; the mass percentage of the first portion of cooked soybeans to the total mass of the first portion of cooked soybeans and the first portion of wheat flour is ≤30%; mixing a second portion of cooked soybeans, a second portion of wheat flour, and a second portion of Aspergillus oryzae for a second koji-making process to prepare a second koji material; the mass percentage of the second portion of cooked soybeans to the total mass of the second portion of cooked soybeans and the second portion of wheat flour is ≥60%; mixing the first koji material with brine for a first fermentation, and then, on days 5-10, 15-20, and after fermentation, respectively, extracting the soy sauce mash from the brine. Fermented crude oil A1, fermented crude oil A2, and fermented crude oil A3 are extracted and combined to form combined crude oil B. The second batch of starter culture is mixed with a portion of combined crude oil B and subjected to a second fermentation under sunlight. During fermentation, crude oil is periodically extracted from the fermented mash and used to irrigate it. Oil is extracted from the fermented mash after the second fermentation to obtain fermented mash crude oil. The fermented mash crude oil is then sun-dried in earthenware jars to obtain soy sauce. The mass percentages of fermented crude oil A1, fermented crude oil A2, and fermented crude oil A3 in combined crude oil B are m1, m2, and m3, respectively, with 0 ≤ m1 ≤ 30%, 0 ≤ m2 ≤ 30%, and 40% ≤ m3 ≤ 100%.

[0046] As a non-limiting example, the mass percentage m1 of fermented crude oil A1 in blended crude oil B can be, but is not limited to, 0%, 1%, 2%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, or any range between two of the above values. Optionally, 0 < m1 ≤ 30%.

[0047] The mass percentage m2 of fermented crude oil A2 in blended crude oil B can be, but is not limited to, 0%, 1%, 2%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, or any range between two of the above values. Optionally, 0 < m2 ≤ 30%.

[0048] The mass percentage (m3) of fermented crude oil A3 in blended crude oil B can be, but is not limited to, 40%, 44%, 48%, 52%, 56%, 60%, 64%, 68%, 72%, 76%, 80%, 84%, 88%, 92%, 96%, 98%, 100%, or any range between two of the above values. Optionally, 40% ≤ m3 < 100%.

[0049] It should be noted that the sum of m1, m2, and m3 is 100%. When m3 = 100%, it means that only fermented crude oil A3 is used as crude oil B for the second fermentation.

[0050] Understandably, the soy sauce brewing method of this application has at least the following beneficial effects:

[0051] (1) In this soy sauce brewing method, cooked soybeans and wheat flour with different raw material ratios are used to make koji, resulting in first koji material and second koji material used for the first fermentation and the second fermentation, respectively. The raw material for making the first koji material uses a high carbon source, which can significantly improve the activity of amylase, saccharifying enzyme, etc.; the raw material for making the second koji material uses a high nitrogen source, which can significantly improve the activity of protease and glutaminase. Thus, by adopting a gradient ratio double koji process, amylase, saccharifying enzyme, protease and glutaminase achieve complementary advantages, and the enzyme activity of the fermentation system is significantly improved.

[0052] (2) In this soy sauce brewing method, double sun-drying (sun-drying of the second fermentation mash and sun-drying of crude oil) and traditional earthenware jar slow brewing process are adopted. The Maillard reaction occurs fully under the sun, which improves the appearance and preservation of the traditional soy sauce. The content of key aroma substances such as 4-ethylguaiacol, HEMF and HDMF in the soy sauce is significantly increased, resulting in a rich aroma and obvious soy sauce flavor.

[0053] It should be noted that the terms "first batch of raw materials," "second batch of raw materials," "first batch production," "second batch production," "first fermentation," and "second fermentation" mentioned in the context are for descriptive purposes only and should not be interpreted as indicating or implying relative importance or quantity, nor should they be interpreted as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," etc., only serve the purpose of non-exhaustive enumeration and should be understood as not constituting a closed limitation on quantity.

[0054] Unrestricted, the method for extracting fermented crude oil A3 from the fermented mash after the first fermentation includes: stirring the fermented mash after the first fermentation is completed evenly and transferring it into a pressing bag, sealing the bag tightly, and pressing it using a heavy stone pressing method to produce the matured crude oil.

[0055] As a non-limiting example, both the first and second fermentations are carried out in earthenware vats.

[0056] In some embodiments, combined crude oil B is added in stages during the second fermentation process. This soy sauce brewing method employs a dynamic, double-fermentation process. During the first fermentation, brine is added, stirred, and kept warm, which helps to ensure that the fermented crude oil has a high sugar content and a strong malt aroma. During the second fermentation, combined crude oil B obtained from the first fermentation is added in stages and gradients. This helps to ensure that the system in the second fermentation process maintains high enzyme activity and the introduction of dominant microorganisms. Furthermore, the entire second fermentation process uses natural brewing and a long-cycle re-oiling process, ensuring that the fermented soy sauce mash has a sweet and savory flavor, a rich body, and a prominent soy sauce aroma. The second fermentation is a long-cycle, traditional earthenware jar fermentation, resulting in a high content of umami amino acids such as glutamic acid in the soy sauce mash.

[0057] It should be noted that the "phased replenishment" mentioned in the context refers to replenishing the combined crude oil B every 10 days starting from the second fermentation, with the mass of the combined crude oil B replenished each time being 0.1 to 0.2 times the mass of the koji material.

[0058] In some embodiments, the total mass of the combined crude oil B added during the second fermentation process is 2.1 to 2.3 times the mass of the second koji material; for example, it can be, but is not limited to, 2.1, 2.2, 2.3 times, or any range between the above two values. Therefore, maintaining a solid-liquid ratio of 2.1 to 2.3 times can maintain a high utilization rate of raw material protein, which is beneficial to the economic value of the produced crude oil.

[0059] It should be noted that the "total mass of combined crude oil B added during the second fermentation process" mentioned in the context refers to the total mass of combined crude oil B added during the entire second fermentation process, that is, the sum of the mass of combined crude oil B added at the beginning of the second fermentation and the mass of combined crude oil B added in subsequent stages.

[0060] As one possible implementation, the salinity of the combined crude oil B added during the second fermentation process is controlled to be between 18°Bé and 22°Bé; for example, it can be, but is not limited to, 18°Bé, 19°Bé, 20°Bé, 21°Bé, 22°Bé, or any range between two of the above salinity levels. This effectively controls the risk of spoilage of the fermented mash during the brewing process.

[0061] In some embodiments, the second fermentation time is ≥6 months. Optionally, the second fermentation time is 6-8 months; for example, it can be, but is not limited to, 6 months, 7 months, 8 months or any range between the above two times.

[0062] As one possible implementation method, the sun-drying time is 30-60 days; for example, it can be, but is not limited to, 30 days, 32 days, 34 days, 36 days, 38 days, 40 days, 42 days, 44 days, 46 days, 48 ​​days, 50 days, 52 days, 54 days, 56 days, 58 days, 60 days, or any range between two of the above times. When the sun-drying time of the crude soy sauce is within the above range, the overall flavor of the soy sauce can be maintained at its best.

[0063] In some embodiments, the brine used for the first fermentation has a salt content of 18°Bé-22°Bé; for example, it can be, but is not limited to, 18°Bé, 19°Bé, 20°Bé, 21°Bé, 22°Bé or any range between two of the above salt contents.

[0064] As one possible implementation, the brine used in the first fermentation has a salt content of 18°Bé-22°Bé, and the mass of the brine is 2.1 to 2.3 times the mass of the first koji material; for example, it can be, but is not limited to, 2.1, 2.2, 2.3 times, or any range between two of the above values. Therefore, maintaining a solid-liquid ratio of 2.1 to 2.3 times can maintain a high utilization rate of raw material protein, which is beneficial to the economic value of the crude oil produced.

[0065] In some embodiments, the temperature of the first fermentation is 20°C-40°C; for example, it can be, but is not limited to, 20°C, 22°C, 24°C, 26°C, 28°C, 30°C, 32°C, 34°C, 36°C, 38°C, 40°C, or any range between two of the above temperatures.

[0066] In some exemplary embodiments, the first fermentation time is ≥3 months.

[0067] Optionally, the first fermentation time is 3 to 5 months; for example, it can be, but is not limited to, 3 months, 4 months, 5 months or any two of the above time ranges.

[0068] In some embodiments, the first fermentation temperature is 30°C-40°C; for example, it can be, but is not limited to, 30°C, 32°C, 34°C, 36°C, 38°C, 40°C, or any two of the above temperatures.

[0069] As one possible implementation, the first fermentation time is 40-60 hours; for example, it can be, but is not limited to, 40 hours, 42 hours, 44 hours, 46 hours, 48 ​​hours, 50 hours, 52 hours, 54 hours, 56 hours, 58 hours, 60 hours, or any range between two of the above times.

[0070] In some embodiments, the mass of the first portion of Aspergillus oryzae is 0.2%-0.7% of the total mass of the first portion of cooked soybeans and the first portion of wheat flour. For example, it can be, but is not limited to, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, or any range between two of the above values.

[0071] In some embodiments, the second fermentation temperature is 30°C-40°C. For example, it can be, but is not limited to, 30°C, 32°C, 34°C, 36°C, 38°C, 40°C, or any range between two of the above temperatures.

[0072] As one possible implementation, the second fermentation time is 40-60 hours; for example, it can be, but is not limited to, 40 hours, 42 hours, 44 hours, 46 hours, 48 ​​hours, 50 hours, 52 hours, 54 hours, 56 hours, 58 hours, 60 hours, or any range between two of the above times.

[0073] In some embodiments, the mass of the second part of Aspergillus oryzae is 0.2%-0.7% of the total mass of the second part of cooked soybeans and the second part of wheat flour. For example, it can be, but is not limited to, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, or any range between two of the above values.

[0074] It should be noted that during the first and second koji-making processes, cooked soybeans are thoroughly mixed with Aspergillus oryzae and wheat flour, so that the Aspergillus oryzae spores and wheat flour coat the surface of the cooked soybeans.

[0075] Non-limitingly, the method for preparing cooked soybeans includes: soaking soybeans in water for 6-14 hours, then adding them to a steamer and steaming over a gentle boil for 30-40 minutes. The soaking time can be, but is not limited to, 6 hours, 8 hours, 10 hours, 12 hours, 14 hours, or any range between two of the above times. The steaming time can be, but is not limited to, 30 minutes, 32 minutes, 34 minutes, 36 minutes, 38 minutes, 40 minutes, or any range between two of the above times.

[0076] In some embodiments, the method for preparing cooked soybeans further includes: selecting soybeans that are plump, intact, uniform in size, fresh, and free from mold before soaking them in water.

[0077] In some embodiments, prior to the step of extracting oil from the mash obtained after the second fermentation, the soy sauce brewing method further includes: using a shovel to remove the mash in the middle (the width of a bamboo basket), slowly inserting the bamboo basket to the bottom of the vat, and scooping out the soy sauce with mash particles from the surface of the bamboo basket every day, repeating this process multiple times until there are no visible fermented soybean particles in the soy sauce inside the basket.

[0078] As one possible implementation method, during the sun-drying process of using earthenware jars to sun-dry the crude soy sauce mash, a glass or bamboo hat is used to cover the jar, and the lid is fixed to the jar with wood or other materials on the opposite side. The mixture is stirred regularly, and salt crystals are removed periodically during the sun-drying process. Hygiene is maintained during the sun-drying process, and attention is paid to preventing insects and flies.

[0079] As a non-restrictive example, such as Figure 1 As shown, the soy sauce brewing method includes the following steps:

[0080] Step S1, Raw material processing: Select plump, whole, uniform, fresh soybeans without mold, put them in a wooden barrel, and soak them in clean water for 6-14 hours; after soaking, put them in a steamer and steam them for 30-40 minutes at a gentle boil.

[0081] Step S2, Koji Making: Use a bamboo basket to drain the cooked soybeans processed in Step S1 until they no longer drip, and spread them out to cool naturally. Weigh out the first portion of cooked soybeans and the second portion of cooked soybeans. Add the first portion of Aspergillus oryzae and the first portion of wheat flour to the first portion of cooked soybeans. Mix the first portion of cooked soybeans with the first portion of Aspergillus oryzae and the first portion of wheat flour thoroughly, so that the spores of the first portion of Aspergillus oryzae and the first portion of wheat flour coat the surface of the first portion of cooked soybeans. The mass of the first portion of cooked soybeans should be ≤30% of the total mass of the first portion of cooked soybeans and wheat flour. After mixing, place the koji material in a bamboo basket, spread it evenly on a bamboo tray, and incubate it in a koji room for 40-60 hours. After that, the surface of the soybean koji will turn yellowish-green, and all the spores will be fully matured, thus obtaining the first koji material. Add a second portion of Aspergillus oryzae and a second portion of wheat flour to a second portion of cooked soybeans. Mix the second portion of cooked soybeans with the second portion of Aspergillus oryzae and the second portion of wheat flour thoroughly, so that the spores of the second portion of Aspergillus oryzae and the second portion of wheat flour coat the surface of the second portion of cooked soybeans. The mass of the second portion of cooked soybeans accounts for ≥60% of the total mass of the second portion of cooked soybeans and the second portion of wheat flour. After mixing, place the koji material in bamboo trays and spread it evenly on bamboo trays. After culturing in a koji room for 40-60 hours, the surface of the soybean koji turns yellow-green and all the spores are fully matured, thus obtaining the second koji material.

[0082] Step S3, First Fermentation: The first batch of starter culture is manually added to the fermentation vat. After the starter culture is added, a brine solution of 18°Bé-22°Bé is added all at once to make the fermented mash. The brine solution is 2.1 to 2.3 times the mass of the first batch of starter culture. The vat is then placed in a warm room (20°C-40°C) for fermentation for at least 3 months. During fermentation, fermented crude oil A1, fermented crude oil A2, and fermented crude oil A3 are extracted from the mash on days 5-10, 15-20, and after fermentation is complete, respectively. Based on the enzyme activity and sensory characteristics of the fermented crude oils, they are combined to form combined crude oil B for use in the second fermentation. The mass percentages of fermented crude oil A1, fermented crude oil A2, and fermented crude oil A3 in combined crude oil B are m1, m2, and m3, respectively, where 0 ≤ m1 ≤ 30%, 0 ≤ m2 ≤ 30%, and 40% ≤ m3 ≤ 100%.

[0083] Step S4, Second Fermentation: The second batch of starter culture is manually added to the fermentation vat. After the starter culture is added, a certain amount of combined crude oil B is added to form a new mash. The mash is then fermented and brewed under sunlight for a long period (i.e., the second fermentation), which takes 6 to 8 months. During the fermentation period, combined crude oil B is added in stages, and crude oil is periodically extracted from the mash to irrigate it. The total mass of combined crude oil B added during the entire fermentation process is 2.1 to 2.3 times the mass of the second batch of starter culture. The salt content of the combined crude oil B added during the fermentation process is controlled at 18°Bé to 22°Bé. The staged addition means that starting from the second fermentation, combined crude oil B is added every 10 days, and the mass of combined crude oil B added each time is 0.1 to 0.2 times the mass of the starter culture.

[0084] Step S5, Extracting Oil: When the crude oil is nearly mature, before releasing the oil, use a curved rake to remove the fermented soy sauce in the middle (the width of a bamboo basket), and slowly insert the bamboo basket to the bottom of the vat. During the process, scoop out the soy sauce with fermented soy sauce particles from the surface of the bamboo basket every day, repeating this process several times until there are no visible fermented soybean particles in the soy sauce inside the basket. Then, extract the oil to obtain the crude fermented soy sauce.

[0085] Step S6, Crude Oil Sun-drying: Crude oil for soy sauce fermentation is sun-dried in earthenware jars. Glass or bamboo lids are used to cover the jars, and wooden or other materials are used to secure them to the sides. Stir regularly, and periodically remove salt crystals during the sun-drying process. Maintain hygiene during the sun-drying process and take precautions against insects and flies. The sun-drying period is controlled to 30-60 days to obtain soy sauce.

[0086] One or more embodiments of this application provide a soy sauce, which is brewed using the soy sauce brewing method described above.

[0087] The technical solutions of this application will be described in detail below with reference to specific embodiments. It should be understood that these embodiments are only for illustrating this application and are not intended to limit the scope of this application. For experimental methods in the following embodiments where specific conditions are not specified, please refer to the guidelines given in this application first, or follow experimental manuals or conventional conditions in the field, or follow the conditions recommended by the manufacturer, or refer to experimental methods known in the field.

[0088] In the specific embodiments described below, the measurement parameters involving raw material components may have slight deviations within the weighing accuracy range unless otherwise specified. Temperature and time parameters are subject to acceptable deviations due to instrument testing accuracy or operational precision.

[0089] I. Preparation of Soy Sauce

[0090] Example 1

[0091] Step S1, Raw material processing: Select plump, intact, uniform-sized, fresh soybeans without mold, put them in a wooden barrel, and soak them in clean water for 6 hours; after soaking, add them to a steamer and steam them for 30 minutes at a gentle boil.

[0092] Step S2, Koji Making: Use a bamboo basket to drain the cooked soybeans processed in Step S1 until they no longer drip, and spread them out to cool naturally. Weigh out the first portion and the second portion of cooked soybeans separately. Add the first portion of Aspergillus oryzae and the first portion of wheat flour to the first portion of cooked soybeans. Mix the first portion of cooked soybeans thoroughly with the first portion of Aspergillus oryzae and the first portion of wheat flour, so that the spores of the first portion of Aspergillus oryzae and the first portion of wheat flour coat the surface of the first portion of cooked soybeans. The mass percentage of the first portion of cooked soybeans is 30% of the total mass of the first portion of cooked soybeans and the first portion of wheat flour, and the mass percentage of the first portion of wheat flour is 70% of the total mass of the first portion of cooked soybeans and the first portion of wheat flour. The amount of the first portion of Aspergillus oryzae added is 0.7% of the total mass of the first portion of cooked soybeans and the first portion of wheat flour. After mixing, put the koji material into a bamboo basket, spread the koji material evenly on a bamboo tray, and incubate it in a koji room for 40 hours. After that, the surface of the soybean koji turns yellowish-green, and all the spores are fully matured, thus obtaining the first koji material. A second portion of Aspergillus oryzae and a second portion of wheat flour were added to a second portion of cooked soybeans. The second portion of cooked soybeans, Aspergillus oryzae, and wheat flour were thoroughly mixed so that the spores of the second portion of Aspergillus oryzae and the second portion of wheat flour coated the surface of the second portion of cooked soybeans. The mass percentage of the second portion of cooked soybeans to the total mass of the second portion of cooked soybeans and the second portion of wheat flour was 70%, and the mass percentage of the second portion of wheat flour to the total mass of the second portion of cooked soybeans and the second portion of wheat flour was 30%. The amount of the second portion of Aspergillus oryzae added was 0.7% of the total mass of the second portion of cooked soybeans and the second portion of wheat flour. After mixing, the koji material was placed in bamboo trays and spread evenly. After 40 hours of cultivation in a koji room, the surface of the soybean koji turned yellowish-green, and all the spores were fully matured, thus obtaining the second koji material.

[0093] Step S3, First Fermentation: The first batch of starter culture is manually added to the fermentation vat. After the starter culture is added, 20°Bé brine is added all at once to make the fermented mash. The brine is 2.1 times the mass of the first batch of starter culture. The vat is then placed in a warm room (20°C-40°C) for 100 days of fermentation. During fermentation, on day 5, day 15, and after fermentation, fermented crude oil A1, fermented crude oil A2, and fermented crude oil A3 are extracted from the fermented mash, respectively. Based on the enzyme activity and sensory characteristics of the fermented crude oil, they are combined to form combined crude oil B for use in the second fermentation. The mass percentages of fermented crude oil A1, fermented crude oil A2, and fermented crude oil A3 in combined crude oil B are m1, m2, and m3, respectively, where m1=30%, m2=30%, and m3=40%.

[0094] Step S4, Second Fermentation: The second batch of starter culture is manually added to the fermentation vat. After the starter culture is added, a certain amount of combined crude oil B is added to form a new fermented mash. The mash is then fermented and brewed under sunlight for a long period (i.e., the second fermentation), which takes 180 days. During the fermentation period, combined crude oil B is added every 10 days, with each addition being 0.1 times the mass of the starter culture. Crude oil is also periodically extracted from the fermented mash and used to irrigate it until the mash has a rich aroma and a mature taste. The total mass of combined crude oil B added during the entire fermentation process is 2.3 times the mass of the second batch of starter culture. The salt content of the combined crude oil B added during the fermentation process is controlled at 22°Bé.

[0095] Step S5, Extracting Oil: When the crude oil is nearly mature, before releasing the oil, use a curved rake to remove the fermented soy sauce in the middle (the width of a bamboo basket), and slowly insert the bamboo basket to the bottom of the vat. During the process, scoop out the soy sauce with fermented soy sauce particles from the surface of the bamboo basket every day, repeating this process several times until there are no visible fermented soybean particles in the soy sauce inside the basket. Then, extract the oil to obtain the crude fermented soy sauce.

[0096] Step S6, Crude Oil Sun-drying: Crude oil for soy sauce mash is sun-dried in earthenware jars, covered with glass lids and secured to the jars with wooden supports. Stir regularly, and periodically remove salt crystals during the sun-drying process. Maintain hygiene during the sun-drying process and take precautions against insects and flies. The sun-drying period is controlled to 60 days to obtain soy sauce.

[0097] Comparative Example 1

[0098] The preparation method of Comparative Example 1 is similar to that of Example 1, except that the first and second koji materials in step S2 of Comparative Example 1 are prepared using the same raw material ratio; all other aspects are the same. Step S2 of Comparative Example 1 is as follows:

[0099] Step S2, Koji Making: Use a bamboo basket to drain the cooked soybeans processed in Step S1 until they no longer drip, and spread them out to cool naturally. Weigh out the first portion and the second portion of cooked soybeans separately. Add the first portion of Aspergillus oryzae and the first portion of wheat flour to the first portion of cooked soybeans. Mix the first portion of cooked soybeans thoroughly with the first portion of Aspergillus oryzae and the first portion of wheat flour, so that the spores of the first portion of Aspergillus oryzae and the first portion of wheat flour coat the surface of the first portion of cooked soybeans. The mass percentage of the first portion of cooked soybeans is 70% of the total mass of the first portion of cooked soybeans and the first portion of wheat flour, and the mass percentage of the first portion of wheat flour is 30% of the total mass of the first portion of cooked soybeans and the first portion of wheat flour. The amount of the first portion of Aspergillus oryzae added is 0.7% of the total mass of the first portion of cooked soybeans and the first portion of wheat flour. After mixing, put the koji material into a bamboo basket, spread the koji material evenly on a bamboo tray, and incubate it in a koji room for 40 hours. After that, the surface of the soybean koji turns yellow-green, and all the spores are fully matured, thus obtaining the first koji material. A second portion of Aspergillus oryzae and a second portion of wheat flour were added to a second portion of cooked soybeans. The second portion of cooked soybeans, Aspergillus oryzae, and wheat flour were thoroughly mixed so that the spores of the second portion of Aspergillus oryzae and the second portion of wheat flour coated the surface of the second portion of cooked soybeans. The mass percentage of the second portion of cooked soybeans to the total mass of the second portion of cooked soybeans and the second portion of wheat flour was 70%, and the mass percentage of the second portion of wheat flour to the total mass of the second portion of cooked soybeans and the second portion of wheat flour was 30%. The amount of the second portion of Aspergillus oryzae added was 0.7% of the total mass of the second portion of cooked soybeans and the second portion of wheat flour. After mixing, the koji material was placed in bamboo trays and spread evenly. After 40 hours of cultivation in a koji room, the surface of the soybean koji turned yellowish-green, and all the spores were fully matured, thus obtaining the second koji material.

[0100] Example 2

[0101] Step S1, Raw material processing: Select plump, intact, uniform-sized, fresh soybeans without mold, put them in a wooden barrel, and soak them in clean water for 14 hours; after soaking, add them to a steamer and steam them for 40 minutes at a gentle boil.

[0102] Step S2, Koji Making: Use a bamboo basket to drain the cooked soybeans processed in Step S1 until they no longer drip, and spread them out to cool naturally. Weigh out the first portion and the second portion of cooked soybeans separately. Add the first portion of Aspergillus oryzae and the first portion of wheat flour to the first portion of cooked soybeans. Mix the first portion of cooked soybeans thoroughly with the first portion of Aspergillus oryzae and the first portion of wheat flour, so that the spores of the first portion of Aspergillus oryzae and the first portion of wheat flour coat the surface of the first portion of cooked soybeans. The mass percentage of the first portion of cooked soybeans is 20% of the total mass of the first portion of cooked soybeans and the first portion of wheat flour, and the mass percentage of the first portion of wheat flour is 80% of the total mass of the first portion of cooked soybeans and the first portion of wheat flour. The amount of the first portion of Aspergillus oryzae added is 0.5% of the total mass of the first portion of cooked soybeans and the first portion of wheat flour. After mixing, put the koji material into a bamboo basket, spread the koji material evenly on a bamboo tray, and incubate it in a koji room for 60 hours. After that, the surface of the soybean koji turns yellowish-green, and all the spores are fully matured, thus obtaining the first koji material. A second portion of Aspergillus oryzae and a second portion of wheat flour were added to a second portion of cooked soybeans. The second portion of cooked soybeans, Aspergillus oryzae, and wheat flour were thoroughly mixed so that the spores of the second portion of Aspergillus oryzae and the second portion of wheat flour coated the surface of the second portion of cooked soybeans. The mass percentage of the second portion of cooked soybeans to the total mass of the second portion of cooked soybeans and the second portion of wheat flour was 60%, and the mass percentage of the second portion of wheat flour to the total mass of the second portion of cooked soybeans and the second portion of wheat flour was 40%. The amount of the second portion of Aspergillus oryzae added was 0.5% of the total mass of the second portion of cooked soybeans and the second portion of wheat flour. After mixing, the koji material was placed in bamboo trays and spread evenly. After 60 hours of cultivation in a koji room, the surface of the soybean koji turned yellowish-green, and all the spores were fully matured, thus obtaining the second koji material.

[0103] Step S3, First Fermentation: The first batch of starter culture is manually added to the fermentation vat. After the starter culture is added, 18°Bé brine is added all at once to make the fermented mash. The brine is 2.3 times the mass of the first batch of starter culture. The vat is then placed in a warm room (20°C-40°C) for 90 days of fermentation. During fermentation, on day 10, day 20, and after fermentation, fermented crude oil A1, fermented crude oil A2, and fermented crude oil A3 are extracted from the fermented mash, respectively. Based on the enzyme activity and sensory characteristics of the fermented crude oil, they are combined to form combined crude oil B for use in the second fermentation. The mass percentages of fermented crude oil A1, fermented crude oil A2, and fermented crude oil A3 in combined crude oil B are m1, m2, and m3, respectively, where m1=20%, m2=20%, and m3=60%.

[0104] Step S4, Second Fermentation: The second batch of starter culture is manually added into the fermentation vat. After the starter culture is added, a certain amount of combined crude oil B is added to form a new fermented mash. This mash is then fermented and brewed under sunlight for a long period (i.e., the second fermentation), which takes 210 days. During the fermentation period, combined crude oil B is added every 10 days, with each addition being 0.2 times the mass of the starter culture. Crude oil is also periodically extracted from the fermented mash and used to irrigate it until the mash has a rich aroma and a mature taste. The total mass of combined crude oil B added during the entire fermentation process is 2.1 times the mass of the second batch of starter culture. The salt content of the combined crude oil B added during the fermentation process is controlled at 18°Bé.

[0105] Step S5, Extracting Oil: When the crude oil is nearly mature, before releasing the oil, use a curved rake to remove the fermented soy sauce in the middle (the width of a bamboo basket), and slowly insert the bamboo basket to the bottom of the vat. During the process, scoop out the soy sauce with fermented soy sauce particles from the surface of the bamboo basket every day, repeating this process several times until there are no visible fermented soybean particles in the soy sauce inside the basket. Then, extract the oil to obtain the crude fermented soy sauce.

[0106] Step S6, Crude Oil Sun-drying: Crude oil for soy sauce mashing is sun-dried in earthenware jars, covered with glass lids and secured to the jars with wooden supports. Stir regularly, and periodically remove salt crystals during the sun-drying process. Maintain hygiene during the sun-drying process and take precautions against insects and flies. The sun-drying period is controlled to 30 days to obtain soy sauce.

[0107] Comparative Example 2

[0108] The preparation method of Comparative Example 2 is similar to that of Example 2, except that the composition of the combined crude oil B in step S3 of Comparative Example 2 is different; everything else is the same. Step S3 of Comparative Example 2 is as follows:

[0109] Step S3, First Fermentation: The first batch of starter culture is manually added to the fermentation vat. After the starter culture is added, 18°Bé brine is added all at once to make the fermented mash. The brine is 2.3 times the mass of the first batch of starter culture. The vat is then placed in a warm room (20°C-40°C) for 90 days of fermentation. During fermentation, on day 10, day 20, and after fermentation, fermented crude oil A1, fermented crude oil A2, and fermented crude oil A3 are extracted from the fermented mash, respectively. Based on the enzyme activity and sensory characteristics of the fermented crude oils, they are combined to form combined crude oil B for use in the second fermentation. The mass percentages of fermented crude oil A1, fermented crude oil A2, and fermented crude oil A3 in combined crude oil B are m1, m2, and m3, respectively, where m1=40%, m2=0%, and m3=60%.

[0110] Comparative Example 3

[0111] The preparation method of Comparative Example 3 is similar to that of Example 2, except that the composition of the combined crude oil B in step S3 of Comparative Example 3 is different; all other aspects are the same. Step S3 of Comparative Example 3 is as follows:

[0112] Step S3, First Fermentation: The first batch of starter culture is manually added to the fermentation vat. After the starter culture is added, 18°Bé brine is added all at once to make the fermented mash. The brine is 2.3 times the mass of the first batch of starter culture. The vat is then placed in a warm room (20°C-40°C) for 90 days of fermentation. During fermentation, on day 10, day 20, and after fermentation, fermented crude oil A1, fermented crude oil A2, and fermented crude oil A3 are extracted from the fermented mash, respectively. Based on the enzyme activity and sensory characteristics of the fermented crude oil, they are combined to form combined crude oil B for use in the second fermentation. The mass percentages of fermented crude oil A1, fermented crude oil A2, and fermented crude oil A3 in combined crude oil B are m1, m2, and m3, respectively, where m1=0%, m2=40%, and m3=60%.

[0113] Example 3

[0114] Step S1, Raw material processing: Select plump, whole, uniform, fresh soybeans without mold, put them in a wooden barrel, and soak them in clean water for 10 hours; after soaking, add them to a steamer and steam them for 35 minutes at a gentle boil.

[0115] Step S2, Koji Making: Use a bamboo basket to drain the cooked soybeans processed in Step S1 until they no longer drip, and spread them out to cool naturally. Weigh out the first portion and the second portion of cooked soybeans separately. Add the first portion of Aspergillus oryzae and the first portion of wheat flour to the first portion of cooked soybeans. Mix the first portion of cooked soybeans thoroughly with the first portion of Aspergillus oryzae and the first portion of wheat flour so that the spores of the first portion of Aspergillus oryzae and the first portion of wheat flour coat the surface of the first portion of cooked soybeans. The mass percentage of the first portion of cooked soybeans to the total mass of the first portion of cooked soybeans and the first portion of wheat flour is 0%, and the mass percentage of the first portion of wheat flour to the total mass of the first portion of cooked soybeans and the first portion of wheat flour is 100%. The amount of the first portion of Aspergillus oryzae added is 0.2% of the mass of the first portion of wheat flour. After mixing, place the koji material in a bamboo basket, spread it evenly on a bamboo tray, and incubate it in a koji room for 50 hours. After that, the surface of the soybean koji turns yellowish-green, and all the spores are fully matured, thus obtaining the first koji material. A second portion of Aspergillus oryzae and a second portion of wheat flour were added to a second portion of cooked soybeans. The second portion of cooked soybeans, Aspergillus oryzae, and wheat flour were thoroughly mixed so that the spores of the second portion of Aspergillus oryzae and the second portion of wheat flour coated the surface of the second portion of cooked soybeans. The mass percentage of the second portion of cooked soybeans to the total mass of the second portion of cooked soybeans and the second portion of wheat flour was 100%, and the mass percentage of the second portion of wheat flour to the total mass of the second portion of cooked soybeans and the second portion of wheat flour was 0%. The amount of the second portion of Aspergillus oryzae added was 0.2% of the mass of the second portion of cooked soybeans. After mixing, the starter culture was placed in bamboo trays and spread evenly. After 50 hours of cultivation in a starter culture room, the surface of the soybean starter culture turned yellowish-green, and all the spores were fully matured, thus obtaining the second starter culture.

[0116] Step S3, First Fermentation: The first batch of starter culture is manually added to the fermentation vat. After the starter culture is added, 22°Bé brine is added all at once to make the fermented mash. The brine is 2.2 times the mass of the first batch of starter culture. The mash is then placed in a warm room (20°C-40°C) for 120 days of fermentation. The fermented mash is stirred evenly and placed into a pressing bag. The bag is sealed tightly and pressed using a heavy stone pressing method to produce the matured crude oil A3, which is used for the second fermentation. The mass percentages of fermented crude oil A1, fermented crude oil A2, and fermented crude oil A3 in the combined crude oil B are m1, m2, and m3, respectively, where m1=0%, m2=0%, and m3=100%.

[0117] Step S4, Second Fermentation: The second batch of starter culture is manually added to the fermentation vat. After the starter culture is added, a certain amount of combined crude oil B is added to form a new mash. The mash is then fermented and brewed under sunlight for a long period (i.e., the second fermentation), which takes 200 days. During the fermentation period, crude oil B is added every 10 days, with each addition being 0.1 times the mass of the starter culture. Crude oil is also periodically extracted from the mash and used to irrigate it until the mash has a rich aroma and a mature taste. The total mass of combined crude oil B added during the entire fermentation process is 2.2 times the mass of the second batch of starter culture. The salt content of the crude oil B added during the fermentation process is controlled at 22°Bé.

[0118] Step S5, Extracting Oil: When the crude oil is nearly mature, before releasing the oil, use a curved rake to remove the fermented soy sauce in the middle (the width of a bamboo basket), and slowly insert the bamboo basket to the bottom of the vat. During the process, scoop out the soy sauce with fermented soy sauce particles from the surface of the bamboo basket every day, repeating this process several times until there are no visible fermented soybean particles in the soy sauce inside the basket. Then, extract the oil to obtain the crude fermented soy sauce.

[0119] Step S6, Crude Oil Sun-drying: Crude oil for soy sauce fermentation is sun-dried in earthenware jars. Bamboo hats are used to cover the jars, and wooden supports are used to secure them to the sides. The mixture is stirred regularly, and salt crystals are periodically removed during the sun-drying process. Hygiene is maintained throughout the sun-drying process, and care is taken to prevent insects and flies. The sun-drying period is controlled to 40 days to obtain soy sauce.

[0120] Comparative Example 4

[0121] The preparation method of Comparative Example 4 is similar to that of Example 3, except that the fermentation time of the second fermentation in step S4 of Comparative Example 4 is 240 days, and the crude oil evaporation in step S6 is not carried out; all other aspects are the same.

[0122] II. Performance Testing

[0123] 1. Enzyme activity was detected in the crude mash obtained after the second fermentation in Examples 1-3 and Comparative Examples 1-3. α-Amylase was detected by iodine colorimetric method, saccharifying enzyme by DNS method, protease by Folin-Ciocalteu method, and glutaminase by ammonia assay method. The enzyme activity dominance of the fermentation system was determined, and the results are shown in Table 1.

[0124] Table 1

[0125]

[0126] 2. The aroma compounds and sensory evaluation of the brewed soy sauces obtained in Examples 1-3 and Comparative Examples 1-4 were analyzed. The sensory evaluation form and its scoring criteria are as follows:

[0127] (1) The appearance, taste and aroma of each sample are evaluated and scored from 1 to 10 (from weak to strong), that is, 1 point is the weakest and 10 points is the strongest; the comprehensive score is the average of the three dimensions.

[0128] (2) The number of samples in the table is set according to the actual test samples, and generally does not exceed 8; the number of evaluators is required to be ≥15 people, and the final sample score is the average of the total number of people's comprehensive scores.

[0129] The test results of Examples 1-3 and Comparative Examples 1-4 are shown in Table 2.

[0130] Table 2

[0131]

[0132] In Table 2, HEMF refers to 4-hydroxy-2(5)-ethyl-5(2)-methyl-3(2H)furan; HDMF refers to 4-hydroxy-2,5-dimethyl-3(2H)-furanone. A comparison of the results of Example 1 and Comparative Example 1 in Tables 1 and 2 shows that, compared to Comparative Example 1, the α-amylase and saccharifying enzyme activities of the crude oil obtained after the second fermentation in Example 1 were significantly increased, and the activities of protease and glutaminase were also somewhat improved; the final brewed soy sauce had higher aroma components and a better overall taste. This indicates that by using a gradient ratio double-cured process, the complementary advantages of amylase, saccharifying enzyme, protease, and glutaminase significantly improved the enzyme activity of the fermentation system.

[0133] As shown in Tables 1 and 2, comparing the results of Example 2 and Comparative Examples 2-3, the dynamic feeding dual fermentation process, which combines crude oil from different stages of the first fermentation and adds it to the second fermentation process in different proportions, maintains the high enzyme activity required by the soy sauce fermentation system while enhancing the flavor and taste of the crude oil mash obtained from the second fermentation. This results in a more prominent aroma in the produced soy sauce, demonstrating a more significant advantage. The scheme that adds all three groups of crude oil yields the best results.

[0134] Comparing the results of Example 3 and Comparative Example 4 in Tables 1 and 2, it can be seen that the total brewing cycle remained consistent. Example 3 employed a double-sun-drying process (sun-drying of the mash and sun-drying of the crude oil) using traditional earthenware jars for slow brewing, resulting in a richer and more robust flavor. The main aroma components, 4-ethylguaiacol, HDMF, and HEMF, were significantly increased, leading to better overall sensory qualities. This indicates that increasing the sun-drying of the crude oil, compared to simply extending the fermentation time, further prolongs the Maillard reaction and significantly enhances the overall flavor of the soy sauce.

[0135] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0136] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for brewing soy sauce, characterized in that, The steps include: The first portion of cooked soybeans, the first portion of wheat flour, and the first portion of Aspergillus oryzae are mixed and then subjected to the first koji-making process to prepare the first koji material; the mass percentage of the first portion of cooked soybeans to the total mass of the first portion of cooked soybeans and the first portion of wheat flour is ≤30%; The second part of cooked soybeans, the second part of wheat flour, and the second part of Aspergillus oryzae are mixed and then subjected to a second koji-making process to prepare the second koji material; the mass percentage of the second part of cooked soybeans to the total mass of the second part of cooked soybeans and the second part of wheat flour is ≥60%; The first batch of starter culture is mixed with salt water and then fermented for the first time. On the 5th-10th day, the 15th-20th day, and after the fermentation is completed, fermented crude oil A1, fermented crude oil A2, and fermented crude oil A3 are extracted from the fermented mash. The fermented crude oil A1, the fermented crude oil A2, and the fermented crude oil A3 are combined to form combined crude oil B. After the second koji material is mixed with a portion of the combined crude oil B, a second fermentation is carried out under sunlight, and during the fermentation period, crude oil is periodically extracted from the mash to irrigate the mash. Oil is extracted from the fermented mash obtained after the second fermentation to obtain crude fermented mash. The crude soy sauce mash is sun-dried in earthenware jars to obtain the soy sauce. The fermented crude oil A1, fermented crude oil A2 and fermented crude oil A3 have the following mass percentages in the combined crude oil B: m1, m2 and m3, respectively, with 0 ≤ m1 ≤ 30%, 0 ≤ m2 ≤ 30%, and 40% ≤ m3 ≤ 100%.

2. The soy sauce brewing method as described in claim 1, characterized in that, During the second fermentation process, the combined crude oil B was continued to be added in stages; Optionally, the total mass of the combined crude oil B added during the second fermentation process is 2.1 to 2.3 times the mass of the second koji material.

3. The soy sauce brewing method as described in claim 1, characterized in that, The salinity of the combined crude oil B added during the second fermentation process is controlled to be 18°Bé-22°Bé.

4. The soy sauce brewing method as described in claim 1, characterized in that, The second fermentation time is ≥6 months, and can be selected as 6-8 months.

5. The soy sauce brewing method as described in claim 1, characterized in that, The drying time is 30-60 days.

6. The soy sauce brewing method as described in claim 1, characterized in that, The salt solution has a salt content of 18°Bé-22°Bé; Optionally, the mass of the brine is 2.1 to 2.3 times the mass of the first koji.

7. The soy sauce brewing method as described in claim 1, characterized in that, The temperature for the first fermentation is 20℃-40℃, and the time is ≥3 months, which is 3-5 months.

8. The soy sauce brewing method according to any one of claims 1 to 7, characterized in that, The first fermentation process takes place at a temperature of 30℃-40℃ for 40-60 hours.

9. The soy sauce brewing method according to any one of claims 1 to 7, characterized in that, The second fermentation process involves a temperature of 30℃-40℃ and a time of 40-60 hours.

10. A soy sauce, characterized in that, It is brewed using the soy sauce brewing method as described in any one of claims 1 to 9.

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