阅读说明：本技术 一种麦芽精酿啤酒发酵工艺 (Fermentation process for malt refined beer ) 是由 全玲峰 于 2021-08-31 设计创作，主要内容包括：本发明公开了一种麦芽精酿啤酒发酵工艺,包括以下步骤：S1：通过氧气将酵母从底部压入前发酵罐内,并继续充氧2～3min；S2：接种后第二天起,每天排杂一次；S3：接种后第二天至封罐前,每天测糖一次；S4：大麦啤酒保持温度8.8～9.2℃、压力0～0.03Mpa至封罐；小麦啤酒保持温度12.8～13.2℃,24小时后升温至18℃、压力0～0.03Mpa至封罐；S5：糖度降到4.0～4.4BX时,大麦啤酒自然升温至12℃,同时封罐、升压至0.09MPa；小麦啤酒保持温度为18℃,同时封罐、升压至0.09MPa；S6：还原结束后,在24小时内降温至0℃,同时保持罐内压力0.09Mpa。(The invention discloses a fermentation process of malt refined beer, which comprises the following steps: s1: pressing the yeast into the fore-fermentation tank from the bottom through oxygen, and continuously oxygenating for 2-3 min; s2: impurities are removed once a day from the next day after inoculation; s3: measuring sugar once every day from the next day after inoculation to before can sealing; s4: keeping the barley beer at the temperature of 8.8-9.2 ℃ and the pressure of 0-0.03 MPa until the barley beer is canned; keeping the temperature of the wheat beer at 12.8-13.2 ℃, heating to 18 ℃ after 24 hours, and sealing the beer tank under the pressure of 0-0.03 MPa; s5: when the sugar degree is reduced to 4.0-4.4 BX, naturally heating the barley beer to 12 ℃, and simultaneously sealing the tank and boosting the pressure to 0.09 MPa; keeping the temperature of the wheat beer at 18 ℃, simultaneously sealing the tank and boosting the pressure to 0.09 MPa; s6: after the reduction is finished, the temperature is reduced to 0 ℃ within 24 hours, and the pressure in the tank is kept at 0.09 MPa.)

1. The fermentation process of the malt refined beer is characterized by comprising the following steps:

s1: inoculating into a tank: pressing the activated yeast into a pre-fermentation tank from the bottom through oxygen, and continuously oxygenating for 2-3 min to uniformly distribute the yeast in the wort;

s2: impurity removal: the next day after inoculation, slowly opening an impurity discharge valve, and discharging condensed solids; removing impurities once a day;

s3: and (3) sugar measurement: the next day after inoculation, samples were taken for sugar testing; measuring sugar once a day before can sealing;

s4: pre-fermentation: ventilating and stirring in the early stage of fermentation, and then keeping the temperature of the barley beer at 8.8-9.2 ℃ and the pressure at 0-0.03 MPa until the barley beer is canned; keeping the temperature of the wheat beer at 12.8-13.2 ℃, heating to 18 ℃ after 24 hours, and sealing the beer tank under the pressure of 0-0.03 MPa;

s5: and (3) sealing the tank and reducing: when the sugar degree of the barley beer is reduced to 4.0-4.4 BX, naturally heating to 12 ℃, keeping, sealing the tank, and boosting the pressure to 0.09 MPa; when the sugar degree of the wheat beer is reduced to 4.0-4.4 BX, keeping the temperature at 18 ℃, and simultaneously sealing the tank and boosting the pressure to 0.09 MPa;

s6: and (3) after-fermentation: after the reduction is complete, CO is used within 24 hours₂Washing the fermentation liquid, cooling to 0 deg.C, and maintaining the pressure in the tank at 0.09 MPa.

2. The malt brew beer fermentation process of claim 1 further comprising: in step S1, the inoculation device, tubing, connectors, and control valves are thoroughly sterilized with 75% medical/food grade alcohol prior to inoculation.

3. The malt brew beer fermentation process of claim 1 further comprising: in step S1, the addition amount of yeast is 0.08-0.12% of the weight of wort.

4. The malt brew beer fermentation process of claim 1 further comprising: in step S4, the time from pre-fermentation to can sealing is 3-4 days for barley beer and 2-3 days for wheat beer.

5. The malt brew beer fermentation process of claim 1 further comprising: in step S5, the jar sealing reduction time is 4 days for barley beer and wheat beer.

6. The malt brew beer fermentation process of claim 1 further comprising: in step S5, after the can is sealed for 4 days, if no diacetyl taste is obvious, the temperature can be reduced; if the diacetyl taste is obvious, the cooling is delayed for 1 to 3 days.

7. The malt brew beer fermentation process of claim 1 further comprising: in step S6, the cooling method includes: cooling to 5 ℃ at the speed of 0.5-0.7 ℃/h, and then cooling to 0 ℃ at the speed of 0.1-0.3 ℃/h.

8. The malt brew beer fermentation process of claim 1 further comprising: in step S6, the post-fermentation time is 3-5 days for barley beer and 1-3 days for wheat beer.

9. The malt brew beer fermentation process of claim 1 further comprising: in step S6, when the temperature is reduced to 5 ℃, recovering the yeast for reuse; if the yeast is not used any more, the yeast is discharged when the temperature is reduced to 2 ℃.

Technical Field

The invention relates to the technical field of beer production and fermentation, in particular to a fermentation process for brewing beer by using malt.

Background

The beer is the beverage with the third global sales rank after water and tea drinking, China is the largest global beer producing country, the beer yield in 2019 reaches 3765.3 ten thousand liters, and the beer yield accounts for about 24.5 percent of the global beer yield; in three quarters before 2020, the beer demand in China is 2832.05 kiloliters, the export amount is 28.35 kiloliters and the export amount is 17639.2 kiloliters.

With the rapid development of economy and the improvement of living standard of people in China, consumption concepts and consumption habits are greatly changed, young consumers continuously seek new experiences, the factors such as the taste and the package of beer are more emphasized, and the low-end beer with original weak taste and rough package is difficult to meet the requirements of the consumers. The appearance of the refined beer provides richer choices for consumers in China, the refined beer is a new high-end product in the beer industry, and the consumers are willing to spend more money to buy the small-batch and manually-made beer instead of the large-batch production beer. As the market of the Chinese refined beer is just started in recent years, according to incomplete statistics, the total number of workshops (including individuals) and enterprises for making the refined beer in China currently is estimated to be 3000-5000. However, the scales of the workshops and enterprises are very small, and the total production of the brewed beer is only about 2.5% of the beer sales volume in addition to the yield of large-scale domestic beer enterprises, the market gap is huge, and the future market demand of the brewed beer is still improved along with the development of bars, high-grade restaurants and night-night industry.

The beer fermentation process is the normal life activity of beer yeast under certain conditions by utilizing the fermentable substances in the wort. The fermentation process is the most critical step in beer brewing, and the flavor and the quality of the obtained finished product wine are different due to different yeast types, fermentation conditions and fermentation modes.

Disclosure of Invention

The invention aims to provide a fermentation process for brewing beer by malt, which improves the traditional beer fermentation process, reasonably adjusts process parameters, improves the production efficiency and quality of the beer, and meets the requirements of consumers on medium-high-end beer products.

In order to achieve the purpose, the invention adopts the following technical scheme:

a fermentation process of malt concentrated beer comprises the following steps:

s1: inoculating into a tank: pressing the activated yeast into a pre-fermentation tank from the bottom through oxygen, and continuously oxygenating for 2-3 min to uniformly distribute the yeast in the wort;

s2: impurity removal: the next day after inoculation, slowly opening an impurity discharge valve, and discharging condensed solids; removing impurities once a day;

s3: and (3) sugar measurement: the next day after inoculation, samples were taken for sugar testing; measuring sugar once a day before can sealing;

s4: pre-fermentation: ventilating and stirring in the early stage of fermentation, and then keeping the temperature of the barley beer at 8.8-9.2 ℃ and the pressure at 0-0.03 MPa until the barley beer is canned; keeping the temperature of the wheat beer at 12.8-13.2 ℃, heating to 18 ℃ after 24 hours, and sealing the beer tank under the pressure of 0-0.03 MPa;

s5: and (3) sealing the tank and reducing: when the sugar degree of the barley beer is reduced to 4.0-4.4 BX, naturally heating to 12 ℃, keeping, sealing the tank, and boosting the pressure to 0.09 MPa; when the sugar degree of the wheat beer is reduced to 4.0-4.4 BX, keeping the temperature at 18 ℃, and simultaneously sealing the tank and boosting the pressure to 0.09 MPa;

s6: and (3) after-fermentation: after the reduction is complete, CO is used within 24 hours₂Washing the fermentation liquid, cooling to 0 deg.C, and maintaining the pressure in the tank at 0.09 MPa.

Further, in step S1, the inoculation device, tubing, connectors, and control valves are fully sterilized with 75% medical/food grade alcohol prior to inoculation.

Further, in step S1, the amount of yeast added is 0.08-0.12% by weight of the wort.

Further, in step S4, the time from pre-fermentation to can-sealing is 3-4 days for barley beer and 2-3 days for wheat beer.

Further, in step S5, the jar-sealing reduction time is 4 days for both barley beer and wheat beer.

Further, in step S5, after the can is sealed for 4 days, if the diacetyl taste is not obvious, the temperature can be reduced; if the diacetyl taste is obvious, the cooling is delayed for 1 to 3 days.

Further, in step S6, the cooling method includes: cooling to 5 ℃ at the speed of 0.5-0.7 ℃/h, and then cooling to 0 ℃ at the speed of 0.1-0.3 ℃/h.

Further, in step S6, the post-fermentation time is 3-5 days for barley beer and 1-3 days for wheat beer.

Further, in step S6, when the temperature is reduced to 5 ℃, the yeast is recovered for reuse; if the yeast is not used any more, the yeast is discharged when the temperature is reduced to 2 ℃.

In the common saying of "no acid does not turn into wine", although the acid does not contribute to the flavor of beer, it is the main flavor-developing substance. The proper amount of acid in the beer ensures that the beer has active and refreshing taste and lacks of dull, sticky and uncomfortable taste; the excessive acid makes the beer have rough, soft and inconsistent taste, and the excessive acid also means that the beer is not fermented normally and is a mark for polluting acid-producing bacteria. Therefore, the control of the total acid content in a reasonable range is an important index for ensuring the wine quality. The fermentation temperature and pressure are key factors of acid production, the acid production amount can be increased in response under the conditions of higher temperature and higher pressure, and the increase of the pressure can also increase the amount of volatile acid dissolved in the beer, so that the acid stimulation of the beer is strong and the acid is exposed; a too high volatile acid content means that the beer has been rancid.

The main products of beer fermentation are alcohol and carbon dioxide, so carbon dioxide is not only unavoidable but also of great benefit to beer. Firstly, in the beer brewing process, the yeast decomposes the fermentable sugar into alcohol and carbon dioxide in an anaerobic environment, and the carbon dioxide can be combined with water to form carbonic acid, so that the effect of reducing the pH value of the beer body and prolonging the shelf life of the beer is achieved, and the effects of removing oxygen in the beer and preventing the beer from being oxidized are also achieved. The carbon dioxide and organic acid in beer have refreshing and refreshing effects. On one hand, the appropriate amount of the tea can reduce the hyperexcitability and the tension, and can promote the muscle relaxation; on the other hand, carbon dioxide stimulates oral nerves and plays a role in promoting digestion. The carbon dioxide in the beer also gives the beer refreshing mouthfeel and abundant foams, and the foams are just that the carbon dioxide in the beer exists in the beer in various forms such as dissolution, adsorption and compounds under certain pressure and low temperature conditions. When the bottle is opened, the carbon dioxide is released from the wine liquid and rises to the liquid surface due to the change of pressure, vibration, splash and the like, and the viscosity of the beer and the existence of some surface active substances, particularly protein, ensure that the foam is not easy to break and is kept for a period of time to form beautiful, white and fine foam accumulation. Therefore, the carbon dioxide acid content in the beer bottle is too low, which affects the product quality.

Diacetyl is a representative, volatile and pungent by-product produced during beer fermentation, and if its content exceeds the threshold of flavour, it will have a rancid flavour. Therefore, the content and degree of reduction of diacetyl in beer are the main indicators of beer maturation. The diacetyl content of the high-quality light beer is required to be controlled below 0.1 mg/L.

Compared with the prior art, the invention has the beneficial effects that:

1. according to the invention, oxygen is oxygenated from the bottom of the fermentation tank, so that oxygen can be distributed in wort more uniformly, and yeast is suspended in the wort, thereby improving the fermentation efficiency; the fermentation process is carried out under the conditions of lower temperature and pressure, and the alcohol concentration, the total acid, the carbon dioxide and the diacetyl content can be controlled within a more reasonable range at the temperature, so that the appearance, the taste and the fragrance of the beer are excellent, and the requirements of medium-high end beer production are met.

2. Although the non-enzymatic decomposition speed of the alpha-acetolactate can be accelerated by increasing the fermentation temperature, and the reduction speed of the diacetyl can be increased, the increase of the temperature has a great influence on the alcohol concentration, the total acid, the carbon dioxide and the diacetyl content, so that the non-enzymatic decomposition speed of the alpha-acetolactate and the synthesis speed of the alpha-acetolactate can be accelerated by adopting a physical method instead of a chemical method and properly ventilating and stirring in the early stage of the primary fermentation, and the generation amount of the diacetyl can be reduced; and in the early stage of after-fermentation, CO is utilized₂The fermentation broth is washed to remove volatile diacetyl. The purpose of reducing diacetyl is achieved on the premise of not affecting other conditions.

Detailed Description

The invention is further illustrated by the following specific examples, but it will be understood that the scope of the invention is not limited by the specific examples.

Example 1

A fermentation process of malt concentrated beer comprises the following steps:

s1: inoculating into a tank: fully disinfecting an inoculation device, a pipeline, a joint and a control valve by using 75% medical/food grade alcohol before inoculation; then pressing the activated yeast into a fore-fermentation tank from the bottom through oxygen, and continuously oxygenating for 2min to uniformly distribute the yeast in the wort; the adding amount of the yeast is 0.1 percent of the weight of the wort;

s2: impurity removal: the next day after inoculation, slowly opening an impurity discharge valve, and discharging condensed solids; removing impurities once a day;

s3: and (3) sugar measurement: the next day after inoculation, samples were taken for sugar testing; measuring sugar once a day before can sealing;

s4: pre-fermentation: in the embodiment, barley beer is aerated and stirred in the early stage of fermentation, and then the temperature is kept at 8.8 ℃ and the pressure is kept at 0.03MPa until the tank is sealed for 4 days;

s5: and (3) sealing the tank and reducing: when the sugar degree is reduced to 4.0BX, naturally raising the temperature to 12 ℃, keeping the temperature, sealing the tank, and raising the pressure to 0.09Mpa for 4 days; after the can is sealed for 4 days, the obvious diacetyl taste exists, and the temperature reduction is delayed for 1 day;

s6: and (3) after-fermentation: after the reduction is complete, CO is used within 24 hours₂Washing the fermentation liquor, then cooling to 5 ℃ at the speed of 0.5 ℃/h, then cooling to 0 ℃ at the speed of 0.1 ℃/h, then maintaining, and simultaneously maintaining the pressure in the tank at 0.09Mpa for 5 days; when the temperature is reduced to 2 ℃, the yeast is discharged.

Example 2

A fermentation process of malt concentrated beer comprises the following steps:

s1: inoculating into a tank: fully disinfecting an inoculation device, a pipeline, a joint and a control valve by using 75% medical/food grade alcohol before inoculation; then pressing the activated yeast into a fore-fermentation tank from the bottom through oxygen, and continuously oxygenating for 2min to uniformly distribute the yeast in the wort; the adding amount of the yeast is 01 percent of the weight of the wort;

s2: impurity removal: the next day after inoculation, slowly opening an impurity discharge valve, and discharging condensed solids; removing impurities once a day;

s3: and (3) sugar measurement: the next day after inoculation, samples were taken for sugar testing; measuring sugar once a day before can sealing;

s4: pre-fermentation: in the embodiment, barley beer is aerated and stirred in the early stage of fermentation, and then the temperature is kept at 9 ℃ and the pressure is kept at 0.02Mpa until the tank is sealed for 4 days;

s5: and (3) sealing the tank and reducing: when the sugar degree is reduced to 4.2BX, naturally raising the temperature to 12 ℃, keeping the temperature, sealing the tank, and raising the pressure to 0.09Mpa for 4 days; after the can is sealed for 4 days, no obvious diacetyl smell exists, and the temperature can be reduced;

s6: and (3) after-fermentation: after the reduction is complete, CO is used within 24 hours₂Washing the fermentation liquor, then cooling to 5 ℃ at the speed of 0.6 ℃/h, then cooling to 0 ℃ at the speed of 0.2 ℃/h, then maintaining, and simultaneously maintaining the pressure in the tank at 0.09Mpa for 4 days; when the temperature is reduced to 5 ℃, the yeast is recovered for reuse.

Example 3

A fermentation process of malt concentrated beer comprises the following steps:

s1: inoculating into a tank: fully disinfecting an inoculation device, a pipeline, a joint and a control valve by using 75% medical/food grade alcohol before inoculation; then pressing the activated yeast into a fore-fermentation tank from the bottom through oxygen, and continuously oxygenating for 2min to uniformly distribute the yeast in the wort; the adding amount of the yeast is 0.1 percent of the weight of the wort;

s2: impurity removal: the next day after inoculation, slowly opening an impurity discharge valve, and discharging condensed solids; removing impurities once a day;

s3: and (3) sugar measurement: the next day after inoculation, samples were taken for sugar testing; measuring sugar once a day before can sealing;

s4: pre-fermentation: in the embodiment, barley beer is aerated and stirred in the early stage of fermentation, and then the temperature is kept at 9.2 ℃ and the pressure is kept at 0Mpa until the tank is sealed for 3 days;

s5: and (3) sealing the tank and reducing: when the sugar degree is reduced to 4.4BX, naturally raising the temperature to 12 ℃, keeping the temperature, sealing the tank, and raising the pressure to 0.09Mpa for 4 days; after the can is sealed for 4 days, no obvious diacetyl smell exists, and the temperature can be reduced;

s6: and (3) after-fermentation: after the reduction is complete, CO is used within 24 hours₂Washing the fermentation liquor, then cooling to 5 ℃ at the speed of 0.7 ℃/h, then cooling to 0 ℃ at the speed of 0.3 ℃/h, then maintaining, and simultaneously maintaining the pressure in the tank at 0.09Mpa for 3 days; when the temperature is reduced to 5 ℃, the yeast is recovered for reuse.

Example 4

A fermentation process of malt concentrated beer comprises the following steps:

s1: inoculating into a tank: fully disinfecting an inoculation device, a pipeline, a joint and a control valve by using 75% medical/food grade alcohol before inoculation; then pressing the activated yeast into a pre-fermentation tank from the bottom through oxygen, and continuously oxygenating for 2-3 min to uniformly distribute the yeast in the wort; the adding amount of the yeast is 0.1 percent of the weight of the wort;

s2: impurity removal: the next day after inoculation, slowly opening an impurity discharge valve, and discharging condensed solids; removing impurities once a day;

s3: and (3) sugar measurement: the next day after inoculation, samples were taken for sugar testing; measuring sugar once a day before can sealing;

s4: pre-fermentation: in the embodiment, the wheat beer is ventilated and stirred in the early stage of fermentation, then the temperature is kept at 12.8 ℃, the temperature is raised to 18 ℃ after 24 hours, the pressure is 0.03MPa, and the time is 2 days;

s5: and (3) sealing the tank and reducing: when the sugar degree is reduced to 4.0BX, keeping the temperature at 18 ℃, simultaneously sealing the tank and boosting the pressure to 0.09MPa for 4 days; after the can is sealed for 4 days, if the diacetyl taste is obvious, the cooling is delayed for 2 days;

s6: and (3) after-fermentation: after the reduction is complete, CO is used within 24 hours₂Washing the fermentation liquor, then cooling to 5 ℃ at the speed of 0.5 ℃/h, then cooling to 0 ℃ at the speed of 0.1 ℃/h, then maintaining, and simultaneously maintaining the pressure in the tank at 0.09Mpa for 3 days; when the temperature is reduced to 5 ℃, the yeast is recovered for reuse.

Example 5

A fermentation process of malt concentrated beer comprises the following steps:

s1: inoculating into a tank: fully disinfecting an inoculation device, a pipeline, a joint and a control valve by using 75% medical/food grade alcohol before inoculation; then pressing the activated yeast into a pre-fermentation tank from the bottom through oxygen, and continuously oxygenating for 2-3 min to uniformly distribute the yeast in the wort; the adding amount of the yeast is 0.1 percent of the weight of the wort;

s2: impurity removal: the next day after inoculation, slowly opening an impurity discharge valve, and discharging condensed solids; removing impurities once a day;

s3: and (3) sugar measurement: the next day after inoculation, samples were taken for sugar testing; measuring sugar once a day before can sealing;

s4: pre-fermentation: in the embodiment, the wheat beer is ventilated and stirred in the early stage of fermentation, then the temperature is kept at 13.0 ℃, the temperature is raised to 18 ℃ after 24 hours, the pressure is 0.02Mpa, and the time is 3 days;

s5: and (3) sealing the tank and reducing: when the sugar degree is reduced to 4.2BX, keeping the temperature at 18 ℃, simultaneously sealing the tank and boosting the pressure to 0.09MPa for 4 days; after the can is sealed for 4 days, no obvious diacetyl smell exists, and the temperature can be reduced;

s6: and (3) after-fermentation: after the reduction is complete, CO is used within 24 hours₂Washing the fermentation liquor, then cooling to 5 ℃ at the speed of 0.6 ℃/h, then cooling to 0 ℃ at the speed of 0.2 ℃/h, then maintaining, and simultaneously maintaining the pressure in the tank at 0.09Mpa for 2 days; when the temperature is reduced to 5 ℃, the yeast is recovered for reuse.

Example 6

A fermentation process of malt concentrated beer comprises the following steps:

s1: inoculating into a tank: fully disinfecting an inoculation device, a pipeline, a joint and a control valve by using 75% medical/food grade alcohol before inoculation; then pressing the activated yeast into a pre-fermentation tank from the bottom through oxygen, and continuously oxygenating for 2-3 min to uniformly distribute the yeast in the wort; the adding amount of the yeast is 0.1 percent of the weight of the wort;

s2: impurity removal: the next day after inoculation, slowly opening an impurity discharge valve, and discharging condensed solids; removing impurities once a day;

s3: and (3) sugar measurement: the next day after inoculation, samples were taken for sugar testing; measuring sugar once a day before can sealing;

s4: pre-fermentation: in the embodiment, the wheat beer is ventilated and stirred in the early stage of fermentation, then the temperature is kept at 13.2 ℃, the temperature is raised to 18 ℃ after 24 hours, the pressure is 0Mpa, and the time is 3 days;

s5: and (3) sealing the tank and reducing: when the sugar degree is reduced to 4.4BX, keeping the temperature at 18 ℃, simultaneously sealing the tank and boosting the pressure to 0.09MPa for 4 days; after the can is sealed for 4 days, if the diacetyl taste is obvious, the temperature reduction is delayed for 3 days;

s6: and (3) after-fermentation: after the reduction is complete, CO is used within 24 hours₂Washing the fermentation broth, cooling to 5 deg.C at a rate of 0.7 deg.C/h, and cooling to 0 deg.C at a rate of 0.3 deg.C/hKeeping the temperature, and keeping the pressure in the tank at 0.09Mpa for 1 day; when the temperature is reduced to 5 ℃, the yeast is recovered for reuse.

Comparative example 1

Basically the same as example 2, except that the wort can temperature was 9 ℃ and the temperature was naturally raised to 11.5 ℃ in step S4, and the pressure was not controlled.

Comparative example 2

Basically the same as example 2, except that in step S5, the pressure was raised to 0.1MPa without changing the temperature.

Comparative example 3

Basically the same as in example 2, except that, in step S6, the temperature was lowered within 36 hours.

Comparative example 4

Basically the same as example 5, except that in step S4, the wort was poured into the tank at 14.5 ℃ and naturally warmed to 20.5 ℃.

Comparative example 5

Basically the same as example 5, except that in step S5, the pressure was increased to 0.1 MPa.

Comparative example 6

Basically the same as in example 5, except that, in step S6, the temperature was lowered within 36 hours.

Comparison experiment of finished wine

According to the requirements of national standard GB4927-2008 of beer and the analysis method in GB/T4928, the indexes of the beer prepared by the fermentation method of the invention in the embodiments 1-6 and the comparative examples 1-6 are detected and subjected to sensory analysis,

1. the results of examining various indexes of the beers prepared by the fermentation methods of examples 1 to 6 and comparative examples 1 to 6 are shown in table 1.

Table 1 test results of each index

As can be seen from Table 1, the indexes of the finished wine obtained by the fermentation processes of examples 1 to 6 and comparative examples 1 to 6 are within the acceptable range. The indexes of the finished wine obtained in the examples 1 to 6 reach the top grade level, while the indexes of the finished wine obtained in the comparative examples 1 to 6 only reach the first grade level. This is because, in comparative examples 1, 3 to 4 and 6, fermentation is actually performed at a relatively high fermentation temperature, while in comparative examples 2 and 5, fermentation is performed under a relatively high pressure, and the fermentation temperature and the fermentation pressure are relatively high, so that the fermentation speed can be increased to some extent and the fermentation time can be shortened, but the aging of yeast is accelerated at a relatively high temperature, the amount of higher alcohols produced is increased, the taste of beer is not good, and the taste is poor. The higher fermentation temperature and pressure make the alcohol concentration, total acid, carbon dioxide and diacetyl content to be higher, and the value is beyond the range of the top grade, so that only the degradation treatment can be carried out.

2. The sensory analysis results are shown in table 2.

TABLE 2 sensory analysis results

As can be seen from Table 2, the appearance of the finished wine obtained in examples 1 to 6 was of the top grade, while the index of the finished wine obtained in comparative examples 1 to 6 was of the first grade. This is because, in comparative examples 1, 3 to 4 and 6, fermentation is actually performed at a relatively high fermentation temperature, while in comparative examples 2 and 5, fermentation is performed under a relatively high pressure, and the fermentation temperature and the fermentation pressure are relatively high, so that the fermentation speed can be increased to some extent and the fermentation time can be shortened, but the aging of yeast is accelerated at a relatively high temperature, the amount of higher alcohols produced is increased, the taste of beer is not good, and the taste is poor. As shown in the data of table 1, the higher fermentation temperature and fermentation pressure make the alcohol concentration, total acid, carbon dioxide, and diacetyl content to be higher, and the alcohol concentration, total acid, carbon dioxide, and diacetyl are the main factors affecting the appearance, foam characteristics, taste, aroma, and flavor, so that the appearance is beyond the range of high grade, and thus only the degradation treatment is performed.

The above-described embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solutions of the present invention can be made by those skilled in the art without departing from the spirit of the present invention, and the technical solutions of the present invention are within the scope of the present invention defined by the claims.