Base liquor preparation method for improving ester aroma and grain aroma of low-alcohol strong-aroma white spirit

Abstract

The invention discloses a preparation method of base liquor for improving ester aroma and grain aroma of low-alcohol strong-aroma white spirit, which is characterized in that the production efficiency of flavor substances such as ethyl hexanoate in the base liquor of the low-alcohol strong-aroma white spirit is remarkably improved through compound functional pit mud enhanced esterifying enzyme activity, multi-grain raw material compound enzyme synergistic hydrolysis and a three-stage temperature control fermentation process; meanwhile, the problems of weak ester fragrance, insufficient grain fragrance, boring wine body and the like which are easily caused by low-alcohol wine are solved through a rear-section esterifying enzyme directional supplementing and double-temperature-zone molecular association aging technology.

Description

Technical Field

[0001] The invention relates to the technical field of liquor brewing, and in particular to a method for preparing a base liquor for enhancing the ester aroma and grain aroma of low-alcohol strong-flavor liquor. Background Art

[0002] The characteristic flavor of Luzhou-flavor liquor relies on esters, primarily ethyl caproate, and grain-flavoring ingredients. Traditionally, the production of low-alcohol liquor (alcohol content ≤42% vol) results in reduced ester solubility and a significant loss of aroma components due to the reduction of the base liquor's alcohol content. Existing technologies primarily address this issue through two approaches: First, the addition of external flavorings, such as a combination of ethyl caproate and ethyl lactate, results in inconsistent aromas and a harsh taste. Second, microbial enhancement, such as the addition of exogenous caproate bacteria, requires strict strain management and carries the risk of poor fermentation stability.

[0003] Furthermore, traditional pit mud is prone to aging (esterase activity below 100 U / g), resulting in inefficient ester synthesis and insufficient release of grain aroma precursors. Therefore, a method that does not rely on exogenous bacterial strains and can achieve natural aroma enhancement in low-alcohol liquors through process optimization is urgently needed. Summary of the Invention

[0004] The main purpose of the present invention is to provide a base wine preparation method and its product for improving the ester aroma and grain aroma of low-alcohol Luzhou-flavor liquor. The method can solve the problems of insufficient flavor fullness and lack of ester aroma and grain aroma of low-alcohol Luzhou-flavor liquor after the alcohol content is reduced, while avoiding the use of exogenous additives.

[0005] A method for preparing a base liquor for enhancing the ester aroma and grain aroma of low-alcohol Luzhou-flavor liquor comprises the following steps:

[0006] (1) Preparing composite functional pit mud: by weight percentage, 50%-55% yellow mud, 20%-25% Luzhou-flavor liquor pit mud, 15%-18% soybean meal powder, 5%-8% liquor tailings, and 2%-3% maltose are mixed, and anaerobically fermented at 35-38° C. for 20-25 days until the esterase activity in the pit mud is ≥180 U / g;

[0007] (2) Pretreatment of multi-grain raw materials: Soak sorghum, rice, glutinous rice, and barley separately, steam until there is no hard core, add complex enzyme and hydrolyze at 50℃ for 2 hours;

[0008] (3) Three-stage temperature-controlled fermentation:

[0009] The composite functional cellar mud in step (1) is applied to the inner wall of a ceramic vat, the mixed raw material hydrolyzed in step (2) is cooled, 15-20 wt% of medium-high temperature Luzhou-flavor Daqu is added, and after mixing, the mixture is poured into the ceramic vat covered with the composite cellar mud for staged fermentation;

[0010] (4) Distillation:

[0011] The distillation is a three-stage distillation. The mash is taken out for distillation. 0.3‰ of the weight of the original grain is taken as the head and retained separately. The distillation is continued until the alcohol content reaches 48%vol or above. The middle part of the wine is the required base wine. The distillation is continued again. The alcohol content between 40%vol-48%vol is the tail part, which is retained separately.

[0012] (5) Dual-temperature molecular association aging

[0013] The middle wine obtained by distillation in step (4) above is used as base wine for staged aging:

[0014] The first stage: the base wine is aged in a ceramic jar at 15-20℃ and 70-80% humidity for 3-4 months;

[0015] The second stage: transfer to stainless steel tanks and store at a constant temperature of 10-15℃ away from light for 1-2 months.

[0016] Preferably, the Luzhou-flavor liquor pit mud in step (1) is taken from a Luzhou-flavor liquor pit that has been used continuously for more than 10 years, and the caproic acid bacteria content in the pit mud is ≥1×10 6 CFU / g.

[0017] Preferably, the tail wine in step (1) is a strong-flavored tail wine, which comes from the tail wine of the distillation of the strong-flavored mash (alcohol content ≤ 42% vol). The tail wine part in step (4) is preferably used to adjust the pH value to 5.5-6.0. By adjusting the pH of the tail wine, the optimal action environment of functional microorganisms and enzymes is created, and miscellaneous bacteria are inhibited. At the same time, the organic components of the tail wine are used to synergistically enhance the function of the cellar mud, and ultimately improve the ester aroma and grain aroma quality of the base wine.

[0018] Preferably, the complex enzyme in step (2) is prepared by compounding α-amylase and cellulase in a mass ratio of 1:2; the added amount is 0.3%-0.5% of the total mass of the raw materials, and the reducing sugar content after hydrolysis is ≥24g / 100g.

[0019] Preferably, in step (2), the raw materials are mixed according to the raw grain mass ratio of 70% sorghum, 15% rice, 10% glutinous rice and 5% barley.

[0020] Preferably, in step (3), the composite functional pit mud is applied to the bottom and sides of the pottery jar with a thickness of 5-10 cm.

[0021] Preferably, the staged fermentation in step (3) is divided into three stages:

[0022] First 0-7 days: Regulate the ambient temperature to keep the center temperature of the mash in the ceramic vat at 20-25°C to promote bacterial enrichment and the production of ethanol and ethyl acetate;

[0023] Middle stage (8-20 days): Regulate the ambient temperature to raise the center temperature of the mash to 32-38°C, activating the microorganisms in the mud to synthesize flavor substances such as caproic acid;

[0024] Later stage 21-38 days: Regulate the ambient temperature to cool the center temperature of the mash in the ceramic vat to 28°C ± 3°C and add 0.1% -0.3% esterification enzyme preparation to carry out catalytic esterification reaction.

[0025] Preferably, the esterification enzyme preparation is prepared by compounding lipase and esterase in a mass ratio of 3:1, with an enzyme activity of ≥5000 U / g and an ethanol concentration resistance of ≥20% vol. The enzyme used is an acid-resistant enzyme (pH 4.5-6.0).

[0026] Preferably, the alcohol content of the middle base wine obtained by distillation in step (4) is between 56% and 67%, the total acid is ≥1.6g / L, and the total ester is ≥4.5g / L.

[0027] As another object of the present invention, the present invention also provides a low-alcohol Luzhou-flavor liquor prepared by the above method, which has an alcohol content of 33%-42% vol, an ethyl hexanoate content ≥1.2g / L, a total ester content ≥2.3g / L, and good sensory evaluation.

[0028] Compared with the existing technology, the present invention significantly improves the production efficiency of flavor substances such as ethyl hexanoate in the base wine of low-alcohol strong-flavor liquor through the strengthening of esterase activity by composite functional pit mud, synergistic hydrolysis of multi-grain raw materials by composite enzymes and a three-stage temperature-controlled fermentation process. At the same time, through the targeted addition of esterase in the latter stage and the dual-temperature zone molecular association aging technology, the problems of weakened ester aroma, insufficient grain aroma and bland wine body that are prone to occur in low-alcohol liquor are solved, so that the product after alcohol reduction (33%-42% vol) still maintains the sensory characteristics of rich ester aroma, coordinated grain aroma and mellow taste, and the total ester content (≥2.3g / L) and flavor stability are better than those of traditional processes, taking into account the dual needs of low alcohol content and fullness of flavor. DETAILED DESCRIPTION

[0029] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] 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 embodiments of the present invention belong. If the definitions set forth in this section are contrary to or otherwise inconsistent with definitions set forth in the patents, patent applications, published patent applications, and other publications incorporated herein by reference, the definitions listed in this section take precedence over the definitions incorporated herein by reference.

[0031] The methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, and instruments used, unless otherwise specified, are conventional in the art and are commercially available to those skilled in the art. When an amount, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper preferred values ​​and lower preferred values, this should be understood to specifically disclose all ranges formed by any pairing of any upper range limit or preferred value with any lower range limit or preferred value, regardless of whether the range is disclosed separately. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted as including the ranges "1 to 4," "1 to 3," "1 to 2," "1 to 2 and 4 to 5," "1 to 3 and 5," etc. When a numerical range is described herein, unless otherwise specified, the range is intended to include the endpoints and all integers and fractions within the range. In the present specification and claims, range definitions may be combined and / or interchanged, and unless otherwise specified, such ranges include all subranges contained therein.

[0032] Example 1

[0033] 1. Materials and Equipment

[0034] 1. Raw materials: The raw grain mass ratio of sorghum, rice, glutinous rice and barley is 70:15:10:5;

[0035] Composite functional cellar mud raw materials: yellow mud 52%, Luzhou-flavor liquor cellar mud (taken from a Luzhou-flavor liquor factory in Sichuan with a 15-year-old cellar, with a caproic acid bacteria content of ≥1.2×10 6 CFU / g) 23%, soybean meal 16%, wine tail (adjusted to pH 6) 7%, maltose 2%;

[0036] Complex enzyme: α-amylase and cellulase (mass ratio 1:2, enzyme activities of 4000U / g and 8000U / g respectively);

[0037] Medium-high temperature Luzhou-flavor Daqu (saccharification capacity ≥800U / g, fermentation capacity ≥1.5g CO2 / 100g·72h);

[0038] Esterifying enzyme preparation: lipase (enzyme activity 6000U / g) and esterase (enzyme activity 2000U / g, mass ratio 3:1).

[0039] 2. Equipment:

[0040] Ceramic vat (500L capacity), constant temperature fermentation room, stainless steel tank (200L), distiller, air conditioner and humidifier to control ambient temperature and humidity.

[0041] 2. Specific implementation steps

[0042] (1) Preparation of composite functional pit mud

[0043] Weigh 52% yellow mud, 23% old cellar mud, 16% soybean meal powder, 7% wine tail, and 2% maltose according to the mass ratio, mix them, and add sterile water to adjust the water content to 40%;

[0044] After anaerobic fermentation at 36°C for 22 days in a sealed fermentation tank, the pit mud esterase activity reached 195 U / g, meeting the requirement of ≥180 U / g. This process effectively promotes the proliferation of esterifying bacteria.

[0045] (2) Pretreatment of multi-grain raw materials

[0046] Soak 105kg of sorghum, 22.5kg of rice, 15kg of glutinous rice, and 7.5kg of barley for 4 hours, then steam until the core is no longer hard.

[0047] After mixing in proportion, 0.4% complex enzyme (α-amylase: cellulase = 1:2) was added, and hydrolyzed at 50°C for 2 hours. The reducing sugar content was measured to be 25.3g / 100g; the mixture was cooled to 28°C and set aside.

[0048] (3) Three-stage temperature-controlled fermentation

[0049] Apply the composite pit mud evenly to the inner wall of the pottery jar (8cm thick), add the hydrolyzed raw materials; add 18% medium-high temperature Luzhou-flavor Daqu, stir evenly, and ferment in a sealed container for 38 days, with temperature control in three stages:

[0050] First stage (0-7 days): The ambient temperature is adjusted to 22-24°C at the center of the mash to promote bacterial enrichment;

[0051] Middle stage (8-20 days): Raise the temperature to 35-37℃ to activate the caproic acid bacteria in the pit mud to synthesize ethyl caproate;

[0052] Later stage (21-38 days): Cool down to 26-28°C, and add 0.2% esterification enzyme preparation (lipase:esterase = 3:1) on the 30th day to strengthen the esterification reaction.

[0053] The esterification enzyme should be added during the later low-temperature period to avoid high-temperature inactivation and improve esterification efficiency.

[0054] (4) Three-stage distillation

[0055] After the mash is distilled, the wine is taken in sections:

[0056] Wine head: take 0.3‰ (about 0.45kg) of the total weight of the raw materials and store it separately;

[0057] Middle base wine: alcohol content 66%vol, total acid 1.8g / L, total ester 5.2g / L;

[0058] Wine tail: The portion below 42% vol alcohol is retained and used for cellar mud reclamation.

[0059] (5) Dual-temperature molecular association aging

[0060] The first stage: the middle base wine is put into ceramic jars and aged for 3 months at 18°C ​​and 75% humidity; the ceramic jar stage promotes molecular association.

[0061] The second stage: transfer to stainless steel tanks and store in the dark at a constant temperature of 12°C for 2 months; the stainless steel tank stage stabilizes the wine structure.

[0062] The final base liquor is reduced to 36% vol as needed and blended into a low-alcohol strong-flavor liquor.

[0063] 3. Product Testing and Sensory Evaluation

[0064] 1. Physical and chemical indicators:

[0065] Alcohol content: 36% vol;

[0066] Total ester content: 2.6g / L (≥2.3g / L);

[0067] Ethyl hexanoate content: 1.4g / L (≥1.2g / L);

[0068] 2. Sensory characteristics:

[0069] Aroma: Ester aroma is prominent (pineapple, apple aroma), and grain aroma (sweet aroma of cooked grains) is coordinated;

[0070] Taste: Sweet and smooth at first, clean and long aftertaste, low alcohol but not bland;

[0071] Style: Typical characteristics of Luzhou-flavor liquor, without the taste of hydrolysis or fusel alcohol stimulation.

[0072] Example 2

[0073] 1. Materials and Equipment

[0074] 1. Raw materials: The raw grain mass ratio of sorghum, rice, glutinous rice and barley is 70:15:10:5;

[0075] Composite functional cellar mud raw materials: yellow mud 50%, Luzhou-flavor liquor cellar mud (taken from a 10-year-old cellar of a Luzhou-flavor liquor factory in Sichuan, with a caproic acid bacteria content ≥1.0×10 6CFU / g) 20%, soybean meal 18%, wine tail (adjusted to pH 5.5) 8%, maltose 3%;

[0076] Complex enzyme: α-amylase and cellulase (mass ratio 1:2, enzyme activities of 4000U / g and 8000U / g respectively);

[0077] Medium-high temperature Luzhou-flavor Daqu (saccharification capacity ≥800U / g, fermentation capacity ≥1.5g CO2 / 100g·72h);

[0078] Esterifying enzyme preparation: lipase (enzyme activity 6000U / g) and esterase (enzyme activity 2000U / g, mass ratio 3:1).

[0079] 2. Equipment:

[0080] Ceramic vat (500L capacity), constant temperature fermentation room, stainless steel tank (200L), distiller, air conditioner and humidifier to control ambient temperature and humidity.

[0081] 2. Specific implementation steps

[0082] (1) Preparation of composite functional pit mud

[0083] Weigh 50% yellow mud, 20% old cellar mud, 18% soybean meal powder, 8% wine tail, and 3% maltose according to the mass ratio, mix them, and add sterile water to adjust the water content to 40%;

[0084] After anaerobic fermentation at 35°C for 22 days in a sealed fermentation tank, the pit mud esterase activity reached 182 U / g, meeting the requirement of ≥180 U / g. This process effectively promotes the proliferation of esterifying bacteria.

[0085] (2) Pretreatment of multi-grain raw materials

[0086] Soak 105kg of sorghum, 22.5kg of rice, 15kg of glutinous rice, and 7.5kg of barley for 4 hours, then steam until the core is no longer hard.

[0087] After mixing in proportion, 0.3% complex enzyme (α-amylase: cellulase = 1:2) was added, and hydrolyzed at 50°C for 2 hours. The reducing sugar content was measured to be 24.5g / 100g; the mixture was cooled to 28°C and set aside.

[0088] (3) Three-stage temperature-controlled fermentation

[0089] Apply the composite pit mud evenly to the inner wall of the pottery jar (8cm thick), add the hydrolyzed raw materials; add 18% medium-high temperature Luzhou-flavor Daqu, stir evenly, and ferment in a sealed container for 38 days, with temperature control in three stages:

[0090] First stage (0-7 days): The ambient temperature is adjusted to 22-24°C at the center of the mash to promote bacterial enrichment;

[0091] Middle stage (8-20 days): Raise the temperature to 35-37℃ to activate the caproic acid bacteria in the pit mud to synthesize ethyl caproate;

[0092] Later stage (21-38 days): Cool down to 26-28°C, and add 0.1% esterification enzyme preparation (lipase:esterase = 3:1) on the 28th day to strengthen the esterification reaction.

[0093] The esterification enzyme should be added during the later low-temperature period to avoid high-temperature inactivation and improve esterification efficiency.

[0094] (4) Three-stage distillation

[0095] After the mash is distilled, the wine is taken in sections:

[0096] Wine head: take 0.3‰ (about 0.45kg) of the total weight of the raw materials and store it separately;

[0097] Middle base wine: alcohol content 65% vol, total acid 1.6g / L, total ester 4.7g / L;

[0098] Wine tail: The portion below 42% vol alcohol is retained and used for cellar mud reclamation.

[0099] (5) Dual-temperature molecular association aging

[0100] The first stage: the middle base wine is put into ceramic jars and aged for 3 months at 18°C ​​and 75% humidity; the ceramic jar stage promotes molecular association.

[0101] The second stage: transfer to stainless steel tanks and store in the dark at a constant temperature of 12°C for 2 months; the stainless steel tank stage stabilizes the wine structure.

[0102] The final base liquor is reduced to 36% vol as needed and blended into a low-alcohol strong-flavor liquor.

[0103] 3. Product Testing and Sensory Evaluation

[0104] 1. Physical and chemical indicators:

[0105] Alcohol content: 36% vol;

[0106] Total ester content: 2.4g / L (≥2.3g / L);

[0107] Ethyl hexanoate content: 1.3g / L (≥1.2g / L);

[0108] 2. Sensory characteristics:

[0109] Aroma: Fresh ester aroma (apple aroma), soft grain aroma, harmonious body;

[0110] Taste: Sweet and smooth at first, clean and long aftertaste, low alcohol but not bland;

[0111] Style: Typical characteristics of Luzhou-flavor liquor, without the taste of hydrolysis or fusel alcohol stimulation.

[0112] Example 3

[0113] 1. Materials and Equipment

[0114] 1. Raw materials: The raw grain mass ratio of sorghum, rice, glutinous rice and barley is 70:15:10:5;

[0115] Composite functional cellar mud raw materials: yellow mud 55%, Luzhou-flavor liquor cellar mud (taken from a 12-year-old cellar of a Luzhou-flavor liquor factory in Hubei, with a caproic acid bacteria content ≥1.0×10 6 CFU / g) 25%, soybean meal 15%, wine tail (adjusted to pH 6.0) 5%, maltose 2%;

[0116] Complex enzyme: α-amylase and cellulase (mass ratio 1:2, enzyme activities of 4000U / g and 8000U / g respectively);

[0117] Medium-high temperature Luzhou-flavor Daqu (saccharification capacity ≥800U / g, fermentation capacity ≥1.5g CO2 / 100g·72h);

[0118] Esterifying enzyme preparation: lipase (enzyme activity 6000U / g) and esterase (enzyme activity 2000U / g, mass ratio 3:1).

[0119] 2. Equipment:

[0120] Ceramic vat (500L capacity), constant temperature fermentation room, stainless steel tank (200L), distiller, air conditioner and humidifier to control ambient temperature and humidity.

[0121] 2. Specific implementation steps

[0122] (1) Preparation of composite functional pit mud

[0123] Weigh 55% yellow mud, 25% old cellar mud, 15% soybean meal powder, 5% wine tail, and 2% maltose according to the mass ratio, mix them, and add sterile water to adjust the water content to 40%;

[0124] After anaerobic fermentation at 37°C for 22 days in a sealed fermentation tank, the pit mud esterase activity reached 195 U / g, meeting the requirement of ≥180 U / g. This process effectively promotes the proliferation of esterifying bacteria.

[0125] (2) Pretreatment of multi-grain raw materials

[0126] Soak 105kg of sorghum, 22.5kg of rice, 15kg of glutinous rice, and 7.5kg of barley for 4 hours, then steam until the core is no longer hard.

[0127] After mixing in proportion, 0.5% complex enzyme (α-amylase: cellulase = 1:2) was added, and hydrolyzed at 50°C for 2 hours. The reducing sugar content was measured to be 26.8g / 100g; the mixture was cooled to 28°C and set aside.

[0128] (3) Three-stage temperature-controlled fermentation

[0129] Apply the composite pit mud evenly to the inner wall of the pottery jar (8cm thick), add the hydrolyzed raw materials; add 18% medium-high temperature Luzhou-flavor Daqu, stir evenly, and ferment in a sealed container for 38 days, with temperature control in three stages:

[0130] First stage (0-7 days): The ambient temperature is adjusted to 22-24°C at the center of the mash to promote bacterial enrichment;

[0131] Middle stage (8-20 days): Raise the temperature to 35-38℃ to activate the caproic acid bacteria in the pit mud to synthesize ethyl caproate;

[0132] Later stage (21-38 days): Cool down to 26-28°C, and add 0.3% esterification enzyme preparation (lipase:esterase = 3:1) on the 28th day to strengthen the esterification reaction.

[0133] The esterification enzyme should be added during the later low-temperature period to avoid high-temperature inactivation and improve esterification efficiency.

[0134] (4) Three-stage distillation

[0135] After the mash is distilled, the wine is taken in sections:

[0136] Wine head: take 0.3‰ (about 0.45kg) of the total weight of the raw materials and store it separately;

[0137] Middle base wine: alcohol content 67%vol, total acid 2g / L, total ester 5.6g / L;

[0138] Wine tail: The portion below 42% vol alcohol is retained and used for cellar mud reclamation.

[0139] (5) Dual-temperature molecular association aging

[0140] The first stage: the middle base wine is put into ceramic jars and aged for 4 months at 18°C ​​and 75% humidity; the ceramic jar stage promotes molecular association.

[0141] The second stage: transfer to stainless steel tanks and store in the dark at a constant temperature of 12°C for 2 months; the stainless steel tank stage stabilizes the wine structure.

[0142] The final base liquor is reduced to 36% vol as needed and blended into a low-alcohol strong-flavor liquor.

[0143] 3. Product Testing and Sensory Evaluation

[0144] 1. Physical and chemical indicators:

[0145] Alcohol content: 36% vol;

[0146] Total ester content: 3.2g / L (≥2.3g / L);

[0147] Ethyl hexanoate content: 1.8g / L (≥1.2g / L);

[0148] 2. Sensory characteristics:

[0149] Aroma: Complex ester aroma (tropical fruit aroma), rich grain aroma (baked cereal aroma), and mellow body;

[0150] Taste: Sweet and smooth at first, clean and long aftertaste, low alcohol but not bland;

[0151] Style: Typical characteristics of Luzhou-flavor liquor, without the taste of hydrolysis or fusel alcohol stimulation.

[0152] Comparative summary of the effects of the embodiments

[0153]

[0154] Comparative Example 1

[0155] Compared with Example 1, this comparative example does not add maltose to the composite functional pit mud, and the rest is the same as Example 1.

[0156] After the base liquor was blended to 36% vol as required, the product testing and sensory evaluation were as follows:

[0157] index Example 1 Comparative Example 1 Total ester content g / L 2.6 2.4 Ethyl hexanoate content g / L 1.4 1.3 Sensory evaluation Harmony of grain aroma and ester aroma Light grain aroma, single ester aroma

[0158] Comparative Example 2

[0159] Compared with Example 1, this comparative example did not add esterase in the latter part of fermentation, and the rest was the same as Example 1.

[0160] After the base liquor was blended to 36% vol as required, the product testing and sensory evaluation were as follows:

[0161] index Example 1 Comparative Example 2 Total ester content g / L 2.6 2.3 Ethyl hexanoate content g / L 1.4 1.2 Sensory evaluation Ester aroma is obvious Slightly weak ester aroma

[0162] Comparative Example 3

[0163] Compared with Example 1, this comparative example added esterase in the early stage of fermentation, and the rest was the same as Example 1.

[0164] After the base liquor was blended to 36% vol as required, the product testing and sensory evaluation were as follows:

[0165] index Example 1 Comparative Example 3 Total ester content g / L 2.6 2.4 Ethyl hexanoate content g / L 1.4 1.3 Sensory evaluation Long-lasting ester fragrance The ester aroma is short-lived and the aftertaste is light

[0166] Comparative Example 4

[0167] Compared with Example 1, this comparative example does not adjust the pH of the wine tail (the original wine tail pH is ≈ 4.2), and the rest is the same as Example 1.

[0168] After the base liquor was blended to 36% vol as required, the product testing and sensory evaluation were as follows:

[0169]

[0170]

[0171] Comparative Example 5

[0172] Compared with Example 1, this comparative example is stored in a ceramic jar at 18° C. and 75% humidity for 5 months without the second stage of low-temperature aging in a stainless steel tank. The rest is the same as Example 1.

[0173] After the base liquor was blended to 36% vol as required, the product testing and sensory evaluation were as follows:

[0174] index Example 1 Comparative Example 5 Total ester content g / L 2.6 2.5 Ethyl hexanoate content g / L 1.4 1.3 Sensory evaluation Soft and mellow taste Slightly loose wine

[0175] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a base liquor for enhancing the ester aroma and grain aroma of low-alcohol Luzhou-flavor liquor, characterized in that: The following steps are involved: (1) Preparing composite functional pit mud: by weight percentage, 50%-55% yellow mud, 20%-25% Luzhou-flavor liquor pit mud, 15%-18% soybean meal powder, 5%-8% liquor tailings, and 2%-3% maltose are mixed, and anaerobically fermented at 35-38° C. for 20-25 days until the esterase activity in the pit mud is ≥180 U / g; (2) Pretreatment of multi-grain raw materials: Soak sorghum, rice, glutinous rice, and barley separately, steam until there is no hard core, add complex enzyme and hydrolyze at 50℃ for 2 hours; (3) Three-stage temperature-controlled fermentation: The composite functional cellar mud in step (1) is applied to the inner wall of a ceramic vat, the mixed raw material hydrolyzed in step (2) is cooled, 15-20 wt% of medium-high temperature Luzhou-flavor Daqu is added, and after mixing, the mixture is poured into the ceramic vat covered with the composite cellar mud for staged fermentation; (4) Distillation: The distillation is a three-stage distillation. The mash is taken out for distillation. 0.3‰ of the weight of the original grain is taken as the head and retained separately. The distillation is continued until the alcohol content reaches 48%vol or above. The middle part of the wine is the required base wine. The distillation is continued again. The alcohol content between 40%vol-48%vol is the tail part, which is retained separately. (5) Dual-temperature molecular association aging The middle wine obtained by distillation in step (4) above is used as base wine for staged aging: The first stage: the base wine is aged in a ceramic jar at 15-20℃ and 70-80% humidity for 3-4 months; The second stage: transfer to stainless steel tanks and store at a constant temperature of 10-15℃ away from light for 1-2 months.

2. The method according to claim 1, characterized in that The Luzhou-flavor liquor pit mud in step (1) is taken from a Luzhou-flavor liquor pit that has been used continuously for more than 10 years, and the caproic acid bacteria content in the pit mud is ≥1×10 6 CFU / g.

3. The method according to claim 1, characterized in that The wine tail in step (1) is a Luzhou-flavor wine tail, which is obtained from the tail section of Luzhou-flavor fermented grains distilled from the fermented grains, and has an alcohol content of ≤42% vol. The pH is adjusted to 5.5-6.0 by using the wine tail. Preferably, the wine tail in step (4) is used. This not only creates an optimal environment for the functional microorganisms and enzymes, but also inhibits the growth of other bacteria. At the same time, it utilizes the organic components of the wine tail to synergistically enhance the function of the cellar mud, ultimately improving the ester and grain aroma quality of the base wine.

4. The method according to claim 1, wherein In step (2), the complex enzyme is prepared by compounding α-amylase and cellulase in a mass ratio of 1:2; the added amount is 0.3%-0.5% of the total mass of the raw materials, and the reducing sugar content after hydrolysis is ≥24g / 100g.

5. The method according to claim 1, wherein In the step (2), the raw materials are mixed according to the raw grain mass ratio of 70% sorghum, 15% rice, 10% glutinous rice and 5% barley.

6. The method according to claim 1, wherein In the step (3), the composite functional pit mud is applied to the bottom and sides of the pottery jar to a thickness of 5-10 cm.

7. The method according to claim 1, characterized in that The staged fermentation in step (3) is divided into three stages: First 0-7 days: Regulate the ambient temperature to keep the center temperature of the mash in the ceramic vat at 20-25°C to promote bacterial enrichment and the production of ethanol and ethyl acetate; Middle stage (8-20 days): Regulate the ambient temperature to raise the center temperature of the mash to 32-38°C, activating the microorganisms in the mud to synthesize flavor substances such as caproic acid; Later stage 21-38 days: Regulate the ambient temperature to cool the center temperature of the mash in the ceramic vat to 28°C ± 3°C and add 0.1% -0.3% esterification enzyme preparation to carry out catalytic esterification reaction.

8. The method according to claim 7, characterized in that The esterification enzyme preparation is prepared by compounding lipase and esterase in a mass ratio of 3:1, with an enzyme activity of ≥5000 U / g and an ethanol concentration resistance of ≥20% vol. The enzyme used is an acid-resistant enzyme.

9. The method according to claim 1, characterized in that The alcohol content of the middle base wine obtained by distillation in step (4) is between 56% and 67%, the total acid is ≥1.6g / L, and the total ester is ≥4.5g / L.

10. The method according to claim 3, characterized in that Use the wine tails from step (4).

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