Wine preparation method for improving flavor by using compound yeast

Abstract

The invention discloses a grape wine preparation method for improving flavor by using compound yeast, and relates to the technical field of grape wine fermentation and flavor improvement. The method comprises the following steps: preparing raw material grape juice, screening and preparing proper yeast strains, adding auxiliary materials, selecting an inoculation mode, controlling fermentation conditions and the like. Non-saccharomyces cerevisiae and saccharomyces cerevisiae are inoculated according to a certain proportion; the yeast nutritional agent is obtained through a specific preparation process, and is added twice to maintain the activity of yeast. And after fermentation is finished, performing low-temperature cold stabilization treatment to optimize the flavor of the wine body. The fruit fragrance, flower fragrance, ester content and terpene content of the grape wine can be remarkably improved, the content of high alcohol and volatile acid is reduced, and the taste and structure are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of wine fermentation and flavor improvement, in particular to a method for preparing wine by utilizing composite yeast to enhance flavor. Background Art

[0002] Wine's unique flavor primarily stems from microbial metabolic activity during fermentation, with aroma components such as esters, higher alcohols, and terpenes playing a key role in the sensory experience. However, traditional industrial brewing relies solely on a single strain of Saccharomyces cerevisiae. While this method offers high fermentation efficiency, it often results in a relatively monotonous aroma profile, making it difficult to develop complex flavor profiles.

[0003] At the same time, naturally fermented grape juice also contains a large number of non-Saccharomyces yeasts. In the past, these strains were often regarded as sources of secondary contamination. However, recent studies have shown that carefully selected non-Saccharomyces yeasts, such as Metschnikowia pulcherrima, Torulaspora delbrueckii, Hansenula spp., and Lachancea thermotolerans, can positively influence flavor components through their metabolic functions.

[0004] For example, the Chinese invention patent application with publication number CN116855396A provides a strain of Hanseniaspora uvarum G2, including its fermentation agent and application. The Hanseniaspora uvarum G2 used is numbered CGMCC No. 25348 and has the excellent characteristic of high production of β-glucosidase (66.03±2.46U / mL). Its application in winemaking can significantly increase the content of esters and alcohols in wine. At the same time, it can also increase the content and types of terpenes in wine, thereby enhancing the flavor complexity of wine.

[0005] Chinese invention patent publication number CN113502233B provides a strain of Maggi yeast and its application in winemaking. A strain of Maggi yeast was obtained through screening. This strain grows well at a low temperature of 4°C. After inoculating this strain into grape juice for low-temperature fermentation, and then using brewer's yeast for alcohol fermentation, a low-alcohol wine with a mellow aroma can be obtained.

[0006] On the one hand, this type of strain often has esterification ability and β-glucosidase activity, which can increase the content of substances such as phenylethyl acetate, isopentanol ester and terpenes (such as β-damascenone and linalool), enhance the fruity and floral aroma characteristics, and effectively inhibit green flavor compounds (such as C6 alcohols).

[0007] Alternatively, sequential inoculation (first with non-Saccharomyces yeast, then with Saccharomyces cerevisiae) can achieve the combined effect of controlled alcohol reduction and aroma enhancement. For example, using Maggi Mechnitzschia or Delburia sporogenes for the initial fermentation, followed by inoculation with Saccharomyces cerevisiae, can reduce final alcohol while increasing the contribution of volatile compounds to the overall aroma profile. This strategy is particularly effective in increasing the concentrations of key aroma components such as ethyl acetate, isobutanol, and 3-methyl-1-butanol.

[0008] Furthermore, different non-Saccharomyces yeast strains can positively impact wine color and structure. For example, Saccharomyces cerevisiae can release mannoproteins, promoting color stability and enhancing taste structure. Thermotolerant Lachancea can produce lactic acid, replacing malolactic fermentation to soften acidity and enrich the taste.

[0009] However, non-brewery yeasts themselves have weak fermentation capabilities and are prone to fermentation stagnation problems. Therefore, their cooperative use in the form of composite inoculation is still the mainstream method for industrial applications.

[0010] In summary, the shift from fermentation yeast alone to a combination of non-Saccharomyces and Saccharomyces is a trend in wine flavor improvement. This not only enhances aroma diversity and structural complexity but also significantly improves product quality through strain synergy. Therefore, designing a complex yeast fermentation method with controllable processes, efficient strain combinations, and suitability for industrial operation has significant practical significance and market prospects. Summary of the Invention

[0011] Based on the problems raised by the above background technology, the present invention proposes a method for preparing wine by using composite yeast to enhance the flavor. By screening dominant non-brewing yeast and compounding it with brewing yeast, the content of flavor substances such as esters, alcohols, acids, terpenes in the wine can be increased, thereby improving the aroma complexity and taste structure.

[0012] The present invention adopts the following technical solutions: A method for preparing wine by using composite yeast to enhance flavor comprises the following steps, calculated by weight: A. Raw material preparation: 1000 portions of grape juice; B. Screen and prepare strains: 50-200 copies of brewer's yeast; 5-100 copies of non-brewer's yeast; C. Accessories: 20-100 parts of sulfur dioxide (calculated as SO2), added after the grape juice in step A is tanked; 5-50 parts of yeast nutrient, add the yeast nutrient in two times, and the amount added in both times is the same; D. Vaccination method: The strains are inoculated by simultaneous inoculation or interval inoculation; Simultaneous inoculation: non-brewers yeast and brewer's yeast are inoculated into grape juice according to the mass ratio for fermentation; Interval inoculation: First inoculate non-brewer yeast into the grape juice, then inoculate brewer yeast to continue fermentation; E. Fermentation conditions: Fermentation temperature: 15-25℃; Fermentation time: 7-30 days, until the specific gravity of the fermentation liquid is ≤1.000; Fermentation broth pH: 3.0-3.8; After fermentation, a wine with enhanced flavor from complex yeasts is produced; The yeast nutrient is prepared by reacting L-cysteine ​​salt, phosphate buffer and limonene.

[0013] Furthermore, the brewer's yeast is in the form of dry powder, with an activity of ≥20×10 9 CFU / g.

[0014] Furthermore, the non-brewery yeast is in the form of dry powder, with an activity of ≥10 8 CFU / g.

[0015] Furthermore, the non-Saccharomyces yeast is selected from one of Hansenula spp., Metschnikowia pulcherrima, and Lachancea thermotolerans.

[0016] Furthermore, the preparation method of the yeast nutrient comprises: H1, reaction step: dissolving 8-22 parts by mass of L-cysteine ​​salt in 70-130 parts by mass of phosphate buffer, adjusting the pH to 7.2-8.3, to obtain solution A; adding 8-22 parts by mass of limonene to solution A, stirring and reacting at 38-47° C. and 130-270 rpm for 2.5-3.5 hours to generate a cysteine-limonene conjugate, to obtain solution B; H2. Post-processing step: spray-drying the solution B obtained in step H1. The inlet air temperature of the spray-drying process is 145-155° C., and the outlet air temperature is 72-78° C. The yeast nutrient is obtained by adjusting the feed rate and atomization pressure. The atomization pressure is 0.2-0.6 MPa.

[0017] Furthermore, the yeast nutrient is added twice, including the first addition immediately upon yeast inoculation and the second addition in the middle and late stages of fermentation when 36-40 wt% of the sugar in the grape juice is consumed.

[0018] Furthermore, in step D, when simultaneous inoculation is used, the mass ratio of non-brewers' yeast to brewer's yeast is 1:10 to 1:4.

[0019] Furthermore, in step D, when interval inoculation is adopted, 5-100 portions of non-brewer's yeast are first inoculated, and then 50-200 portions of brewer's yeast are inoculated after fermentation for 48-72 hours.

[0020] Furthermore, the step E is carried out in a closed fermentation tank, with static or light stirring, 1-2 times a day.

[0021] Furthermore, in step E, after the fermentation is completed, the obtained wine is cold-stabilized at 0-4° C. for 3-7 days.

[0022] Reaction mechanism of the present invention: Composite yeast synergistic metabolism and flavor construction: non-brewing yeast and brewing yeast divide the work and cooperate with each other. Non-brewing yeast secretes esterases, glycosidases, etc. to convert grape substances into flavor substances such as esters and free terpenes, and produce polyols and organic acids to improve the wine body; brewing yeast undergoes alcoholic fermentation to produce higher alcohols that constitute the aroma skeleton. The metabolites of non-brewing yeast and brewing yeast interact with each other to form a complex aroma network.

[0023] The thiol-olefin addition reaction synergizes nutritional flavor: Under weakly alkaline conditions, the thiol group of cysteine ​​is converted into a thiol anion, which undergoes a nucleophilic addition reaction with the double bond of limonene to form a cysteine-limonene conjugate. This conjugate decomposes during fermentation, and the limonene derivative acts as a terpene precursor and is converted into monoterpenoid compounds, imparting characteristic flavor to the wine. Meanwhile, the phosphate buffer maintains pH stability.

[0024] Compared with the prior art, the present invention has the following beneficial effects: 1. Compared with pure strain fermentation of a single strain of Saccharomyces cerevisiae, this invention significantly increases total ester content, specific ethyl esters by ≥30%, and terpenes, while maintaining or slightly reducing the levels of the higher alcohols isopentanol and isobutanol. The aroma is more complex and layered, the taste is smoother and more delicate, and the aftertaste is longer.

[0025] 2. Significantly improved flavor: Through the synergistic fermentation of complex yeasts and the decomposition of conjugates to generate flavor substances, the ester content and terpenes in the wine are increased, adding new aroma layers such as floral and tropical fruit aromas, with a fuller taste and softer acidity.

[0026] 3. Stable and controllable quality: By precisely controlling the inoculation method, fermentation conditions, and the use of additives, the risk of oxidation and the generation of undesirable flavors are reduced, and the shelf life of the finished wine is extended by 10-15%. The flavor can be customized according to the grape variety, achieving stable industrial production of high-quality wine. DETAILED DESCRIPTION

[0027] The following embodiments of the present invention are provided to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] It should be noted that among the non-Saccharomyces yeasts used in the following examples and comparative examples, Hansenula spp. represents Hansenula spp., Metschnikowia pulcherrima represents Metschnikowia pulcherrima, and Lachancea thermotolerans represents Lachancea thermotolerans, and therefore only the Chinese names are cited.

[0029] Example 1 A. Raw material preparation: prepare 1000g grape juice.

[0030] B. Screening and preparation of bacterial strains: 50 g of brewer's yeast and 5 g of non-brewer's yeast, wherein the non-brewer's yeast is Hansenula; wherein the brewer's yeast is in the form of dry powder, with an activity of ≥ 20 × 10 9 CFU / g, non-crystalactic yeast in dry powder form, activity ≥10 8 CFU / g.

[0031] C. Accessories: 20g of sulfur dioxide (as SO2), added after the grape juice in step A is tanked; 5g of a yeast nutrient is prepared by dissolving 8g of L-cysteine ​​hydrochloride in 70g of phosphate buffer and adjusting the pH to 7.2 to obtain solution A. 8g of limonene is added to solution A and stirred at 38°C and 130 rpm for 2.5 hours to produce a cysteine-limonene conjugate, obtaining solution B. Solution B is spray-dried at an inlet air temperature of 145°C and an outlet air temperature of 72°C. The feed rate and atomization pressure are adjusted to obtain the yeast nutrient. The atomization pressure is 0.2 MPa. The yeast nutrient is added in two additions: the first addition immediately upon yeast inoculation and the second addition in the middle and late stages of fermentation, when 36wt% of the grape juice sugar has been consumed.

[0032] D. Yeast inoculation method: Use interval inoculation, first inoculate 5g of non-brewer's yeast into the grape juice, then inoculate 50g of brewer's yeast after fermentation for 48 hours and continue fermentation.

[0033] E. Fermentation conditions: The fermentation temperature was controlled at 15°C; The fermentation time is 7 days, until the specific gravity of the fermentation liquid is ≤1.000; The pH of the fermentation broth was 3.0; The above step E is carried out in a closed fermentation tank with mild stirring, twice a day.

[0034] Example 2 A. Raw material preparation: prepare 1000g grape juice.

[0035] B. Screening and preparation of strains: 125 g of brewer's yeast and 52.5 g of non-brewer's yeast were taken. The non-brewer's yeast was selected from Maggi yeast. The brewer's yeast was in the form of dry powder with an activity of ≥ 20 × 10 9 CFU / g, non-crystalactic yeast in dry powder form, activity ≥10 8 CFU / g.

[0036] C. Accessories: 60g of sulfur dioxide (as SO2), added after the grape juice in step A is tanked; 27.5g of yeast nutrient was prepared by dissolving 15g of L-cysteine ​​hydrochloride in 100g of phosphate buffer and adjusting the pH to 7.75. 15g of limonene was added and the mixture was stirred at 42.5°C and 200 rpm for 3 hours. The mixture was then spray-dried with an inlet air temperature of 150°C and an outlet air temperature of 75°C, adjusting the feed rate and atomization pressure of 0.4MPa. The mixture was added in two stages: the first at yeast inoculation and the second in the middle to late fermentation period, when the grape juice sugar content was approximately 38wt%.

[0037] D. Yeast inoculation method: simultaneous inoculation is adopted, with the mass ratio of non-brewers yeast to brewer's yeast being 1:5 and both yeasts are inoculated into grape juice for fermentation.

[0038] E. Fermentation conditions: The fermentation temperature was controlled at 18°C; The fermentation time is 18 days, until the specific gravity of the fermentation liquid is ≤1.000; The pH of the fermentation broth was 3.4; The above step E is carried out in a closed fermentation tank with mild stirring, twice a day.

[0039] Example 3 A. Raw material preparation: prepare 1000g grape juice.

[0040] B. Screening and preparation of strains: 175 g of brewer's yeast and 77.5 g of non-brewer's yeast were taken. The non-brewer's yeast was selected from the heat-resistant Lachancea yeast. The brewer's yeast was in the form of dry powder with an activity of ≥20 × 10 9 CFU / g, non-crystalactic yeast in dry powder form, activity ≥10 8 CFU / g.

[0041] C. Accessories: 80g of sulfur dioxide (as SO2), added after the grape juice in step A is tanked; 42.5g of yeast nutrient, prepared as follows: 20g of L-cysteine ​​hydrochloride is dissolved in 120g of phosphate buffer and the pH is adjusted to 8.0; 20g of limonene is added to the solution and stirred at 45°C and 240 rpm for 3.25 hours to produce a cysteine-limonene conjugate; the mixed solution is spray-dried at an inlet air temperature of 153°C and an outlet air temperature of 76°C. The feed rate and atomization pressure of 0.5MPa are adjusted to obtain the yeast nutrient. The yeast nutrient is added in two steps: the first immediately upon yeast inoculation and the second in the middle and late stages of fermentation, when the grape juice sugar content is approximately 39wt%.

[0042] D. Yeast inoculation method: Use interval inoculation, first inoculate 77.5g of non-brewer's yeast into the grape juice, and then inoculate 175g of brewer's yeast after fermentation for 60 hours to continue fermentation.

[0043] E. Fermentation conditions: The fermentation temperature was controlled at 22°C; The fermentation time is 24 days, until the specific gravity of the fermentation liquid is ≤1.000; The pH of the fermentation broth was 3.6; The above step E is carried out in a closed fermentation tank with mild stirring, twice a day.

[0044] Example 4 A. Raw material preparation: prepare 1000g grape juice.

[0045] B. Screening and preparation of strains: Take 200g of brewer's yeast and 100g of non-brewer's yeast, the non-brewer's yeast being Hansenula; wherein the brewer's yeast is in the form of dry powder, with an activity of ≥20×10 9 CFU / g, non-crystalactic yeast in dry powder form, activity ≥10 8 CFU / g.

[0046] C. Accessories: 100g of sulfur dioxide (as SO2), added after the grape juice in step A is tanked; 50g of yeast nutrient is prepared by dissolving 22g of L-cysteine ​​hydrochloride in 130g of phosphate buffer and adjusting the pH to 8.3; adding 22g of limonene and stirring at 47°C and 270 rpm for 3.5 hours; then spray drying with an inlet air temperature of 155°C and an outlet air temperature of 78°C, adjusting the feed rate and atomization pressure of 0.6MPa. Add the nutrient in two steps: the first at yeast inoculation and the second in the middle to late fermentation period, when the grape juice has consumed approximately 40wt% of its sugar content.

[0047] D. Yeast inoculation method: Inoculate simultaneously, with the mass ratio of non-brewer yeast to brewer yeast being 1:4, and inoculate into grape juice for fermentation.

[0048] E. Fermentation conditions: The fermentation temperature was controlled at 25°C; The fermentation time is 30 days, until the specific gravity of the fermentation liquid is ≤1.000; The pH of the fermentation broth was 3.8; The above step E is carried out in a closed fermentation tank with mild stirring, twice a day.

[0049] Comparative Example 1 A. Raw material preparation: prepare 1000g grape juice.

[0050] B. Screening and preparation of bacterial strains: 50 g of brewer's yeast and 5 g of non-brewer's yeast, wherein the non-brewer's yeast is Hansenula; wherein the brewer's yeast is in the form of dry powder, with an activity of ≥ 20 × 10 9 CFU / g, non-crystalactic yeast in dry powder form, activity ≥10 8 CFU / g.

[0051] C. Accessories: 20g of sulfur dioxide (as SO2), added after the grape juice in step A is tanked; 5g of yeast nutrient was prepared by adding 8g of limonene to 70g of phosphate buffer, adjusting the pH to 7.2, and stirring at 38°C and 130 rpm for 2.5 hours. After the reaction, the mixed solution was spray-dried at an inlet air temperature of 145°C and an outlet air temperature of 72°C. The feed rate and atomization pressure of 0.2 MPa were adjusted to obtain the yeast nutrient. The yeast nutrient was added in two steps: the first step immediately upon yeast inoculation and the second step in the middle and late stages of fermentation, when the grape juice sugar content was approximately 36wt%.

[0052] D. Yeast inoculation method: Use interval inoculation, first inoculate 5g of non-brewer's yeast into the grape juice, and then inoculate 50g of brewer's yeast after fermentation for 48 hours to continue fermentation.

[0053] E. Fermentation conditions: The temperature is controlled at 15°C; The fermentation time is 7 days, until the specific gravity of the fermentation liquid is ≤1.000; The pH of the fermentation broth was 3.0; The above step E is carried out in a closed fermentation tank with mild stirring, twice a day.

[0054] Comparative Example 2 A. Raw material preparation: prepare 1000g grape juice.

[0055] B. Screening and preparation of bacterial strains: 50 g of brewer's yeast and 5 g of non-brewer's yeast, wherein the non-brewer's yeast is Hansenula; wherein the brewer's yeast is in the form of dry powder, with an activity of ≥ 20 × 10 9 CFU / g, non-crystalactic yeast in dry powder form, activity ≥10 8 CFU / g.

[0056] C. Accessories: 20g of sulfur dioxide (as SO2), added after the grape juice in step A is tanked; 5g of yeast nutrient was prepared by adding 8g of L-cysteine ​​hydrochloride to 70g of phosphate buffer, adjusting the pH to 7.2, and stirring at 38°C and 130 rpm for 2.5 hours. After the reaction, the mixed solution was spray-dried at an inlet air temperature of 145°C and an outlet air temperature of 72°C. The feed rate and atomization pressure of 0.2 MPa were adjusted to obtain the yeast nutrient. The yeast nutrient was added in two steps: the first step immediately upon yeast inoculation and the second step in the middle and late stages of fermentation, when the grape juice sugar content was approximately 36wt%.

[0057] D. Yeast inoculation method: Use interval inoculation, first inoculate 5g of non-brewer's yeast into the grape juice, and then inoculate 50g of brewer's yeast after fermentation for 48 hours to continue fermentation.

[0058] E. Fermentation conditions: The temperature is controlled at 15°C; The fermentation time is 7 days, until the specific gravity of the fermentation liquid is ≤1.000; The pH of the fermentation broth was 3.0; The above step E is carried out in a closed fermentation tank with mild stirring, twice a day.

[0059] Test method and results of the present invention: 1) Sample preparation: The fermented wine samples were extracted using liquid-liquid extraction (methylene chloride as the solvent and 1-octanol as the internal standard) and then concentrated for analysis. This method has been validated and demonstrates good linearity and reproducibility. The volatile aroma compounds were pre-concentrated using HS-SPME and subsequently quantified by GC-MS analysis.

[0060] 2) Quantitative analysis: Total esters and phenylethyl acetate were quantified by GC-MS using standards for calibration; β-damascus terpenes were assessed using OAV (Aroma Activity Value); higher alcohols (isoamyl alcohol) and volatile acids (e.g., caprylic acid, acetic acid) were measured using the methods recommended by the International Wine Organization (OIV).

[0061] 3) Sensory evaluation This study involved 15 professional wine tasters blindly evaluating samples. The wines were scored on aroma complexity, fruity and floral notes, mouthfeel softness, structural balance, and aftertaste using a 0-100 scale. Details are shown in Tables 1 and 2.

[0062] Table 1 Quantitative test results

[0063] Table 2 Sensory evaluation results

[0064] It can be seen from the test results of the above embodiments and comparative examples that the present invention can effectively increase the total ester content, making the wine aroma more complex, the layered feeling enhanced, the taste smoother and more delicate, and the aftertaste long.

[0065] 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 wine by using a composite yeast to enhance the flavor, characterized by: According to parts by mass, the method comprises the following steps: A. Raw material preparation: 1000 parts of grape juice; B. Screening and preparation of bacterial strains: 50-200 parts of brewer's yeast; 5-100 parts of non-brewer's yeast; C. Accessories: 20-100 parts of sulfur dioxide, added after the grape juice in step A is tanked; 5-50 parts of yeast nutrient, add the yeast nutrient in two times, and the amount added in both times is the same; D. Vaccination method: The strains are inoculated by simultaneous inoculation or interval inoculation; Simultaneous inoculation: non-brewers yeast and brewer's yeast are inoculated into grape juice according to the mass ratio for fermentation; Interval inoculation: First inoculate non-brewer yeast into the grape juice, then inoculate brewer yeast to continue fermentation; E. Fermentation conditions: Fermentation temperature: 15-25℃; Fermentation time: 7-30 days, until the specific gravity of the fermentation liquid is ≤1.000; Fermentation broth pH: 3.0-3.8; After fermentation, a wine with enhanced flavor from complex yeasts is produced.

2. The method for preparing wine by using composite yeast to enhance flavor according to claim 1, characterized in that: The brewer's yeast is in the form of dry powder, with an activity of ≥20×10 9 CFU / g.

3. The method for preparing wine by using composite yeast to enhance flavor according to claim 1, characterized in that: The non-brewery yeast is in the form of dry powder, with an activity of ≥10 8 CFU / g.

4. The method for preparing wine by using composite yeast to enhance flavor according to claim 1, characterized in that: The non-brewery yeast is selected from one of Hansenula, Maggi, and Lachancea thermotolerant.

5. The method for preparing wine by using composite yeast to enhance flavor according to claim 1, characterized in that: The preparation method of the yeast nutrient comprises, by mass fraction: H1, reaction step: dissolving 8-22 parts of L-cysteine ​​salt in 70-130 parts of phosphate buffer and adjusting the pH to 7.2-8.3 to obtain solution A; Add 8-22 parts of limonene to solution A, stir and react at 38-47° C. and 130-270 rpm for 2.5-3.5 hours to generate a cysteine-limonene conjugate, thereby obtaining solution B; H2. Post-processing step: spray-drying the solution B obtained in step H1. The inlet air temperature of the spray-drying process is 145-155° C., and the outlet air temperature is 72-78° C. The yeast nutrient is obtained by adjusting the feed rate and atomization pressure. The atomization pressure is 0.2-0.6 MPa.

6. The method for preparing wine by using composite yeast to enhance flavor according to claim 1, characterized in that: The yeast nutrient is added twice, including the first addition immediately upon yeast inoculation and the second addition in the middle and late stages of fermentation when 36-40 wt% of the grape juice sugar is consumed.

7. The method for preparing wine by using composite yeast to enhance flavor according to claim 1, characterized in that: In the step D, when the simultaneous inoculation is adopted, the mass ratio of the non-brewer's yeast to the brewer's yeast is 1:10 to 1:

4.

8. The method for preparing wine by using composite yeast to enhance flavor according to claim 1, characterized in that: In the step D, when the interval inoculation is adopted, 5-100 portions of non-brewer's yeast are first inoculated, and then 50-200 portions of brewer's yeast are inoculated after fermentation for 48-72 hours.

9. The method for preparing wine by using composite yeast to enhance flavor according to claim 1, characterized in that: The step E is carried out in a closed fermentation tank, statically or with slight stirring, 1-2 times a day.

10. The method for preparing wine by using composite yeast to enhance flavor according to claim 1, characterized in that: In the step E, after the fermentation is completed, the obtained wine is cold-stabilized at 0-4° C. for 3-7 days.

Images