A strong beer with rich fruity aroma and its preparation method

Abstract

The present invention provides a strong beer with rich fruity aroma and a preparation method thereof, belonging to the field of beer brewing, and capable of solving the technical problem that it is difficult to brew high-alcohol beer with an alcohol content greater than 9% in the existing beer brewing technology. The strong beer with rich fruity aroma of the present invention uses malt, wheat malt, and syrup as the main raw materials, and is prepared by bottom-fermentation yeast. By optimizing the malt raw materials, changing the syrup addition position, adjusting the fermentation process, etc., a strong beer with a strong body, rich fruity aroma, mellow, full, harmonious and sweet aftertaste is finally prepared. Its original wort concentration is 28-30°P, the alcohol content is ≥12.0% vol, the alcohol-ester ratio is 1.2-2.5, the RDF is between 65-68%, the total ester content in the beer is >50 mg / L, and the higher alcohols are <120 mg / L. The present invention can be applied to the production of strong beer.

Description

Technical Field

[0001] The present invention belongs to the field of beer brewing, and particularly relates to a strong beer with rich fruity aroma and a preparation method thereof. Background Art

[0002] With the continuous improvement of the consumption level, consumers' demands for beer flavors are more diversified and characteristic. The light beer flavor can no longer meet consumers' demands for personalized and characteristic beer products.

[0003] High-alcohol beer refers to beer products with an alcohol content exceeding 5% vol. Such beers are mainly known for their high alcohol content, strong taste, and rich and mellow flavor. Through market research by the British research institution Euromonitor International, it is found that the growth rate of high-alcohol beer is remarkable and it is particularly popular in the Asia-Pacific and Western European markets. In the beer classification, beers with an alcohol content of 6-9% are defined as high-alcohol beers; while an alcohol content greater than 9% is called an extremely high-alcohol content. In the field of beer brewing, the brewing technology for high-alcohol beer with an alcohol content greater than 9% has always been a difficult problem.

[0004] As is well known, beer yeast, brewing process, raw materials, etc. are all key factors affecting beer flavor. However, how to improve the above content, how to achieve the preparation of ultra-high-concentration wort in the process, and at the same time meet the normal high-concentration fermentation to prepare a strong beer with rich flavor, distinct characteristics and an alcohol content greater than 10% is an important topic studied by those skilled in the art. Summary of the Invention

[0005] In view of the technical problem that the existing beer brewing technology is difficult to achieve the brewing of high-alcohol beer with an alcohol content greater than 9%, the present invention provides a strong beer with rich fruity aroma and a preparation method thereof, which can brew a strong beer with rich fruity aroma, strong flavor characteristics and good drinkability on the premise of ensuring normal fermentation, and can meet consumers' special needs for strong beer.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A strong beer with rich fruity aroma, the beer is prepared by using malt, wheat malt and syrup as the main raw materials and fermenting with bottom yeast, the original wort concentration of the beer is 28-30 °P, the alcohol content ≥ 12.0% vol, the alcohol-ester ratio is 1.2-2.5, and the RDF is between 65-68%.

[0008] In one embodiment, the total ester content in the beer > 50 mg / L, and the higher alcohols < 120 mg / L.

[0009] In one embodiment, the total addition ratio of barley malt and wheat malt is 40 - 50% by weight, and the addition ratio of syrup is 50 - 60% by weight.

[0010] In one embodiment, by weight percentage, the addition amount of barley malt accounts for 70 - 80% of the total mass of malt, and wheat malt accounts for 20 - 30% of the total mass of malt. Among them, the α-N content of the barley malt is controlled at 140 - 170 mg / 100 g, and the α-N content of the wheat malt is controlled at 180 - 220 mg / 100 g.

[0011] In one embodiment, the syrup is corn starch syrup or malt syrup, and its solid content is 80%.

[0012] The present invention also provides a preparation method of the strong beer described in any one of the above embodiments, including the following steps:

[0013] Mashing: Select barley malt and wheat malt as the main raw materials, mix them in a ratio of 1:(2.8 - 3.0) of material to water and add them to the mashing pot, and carry out a segmented mashing process at 45 - 78 °C;

[0014] Wort filtration: After mashing is completed, when the iodine test is qualified, carry out wort filtration and lauter, and obtain unboiled whole wheat wort;

[0015] Wort boiling: Transfer the unboiled whole wheat wort to the boiling pot for boiling, control the boiling time and boiling evaporation rate, and add hops or hop products during the boiling process;

[0016] Wort cooling: The boiled whole wheat wort is subjected to whirlpool precipitation, and syrup is added before wort cooling so that it is fully mixed with the hot wort after whirlpool precipitation, and then enters the thin plate cooling device to cool the mixed syrup and whole wheat wort, and obtain cooled wort of 28 - 30 °P;

[0017] Fermentation: The cooled wort is aerated and inoculated with beer yeast, put into the fermentation tank, and fermented at the main fermentation temperature of 18 - 20 °C to obtain the fermented liquor;

[0018] Liquor filtration and dilution: The fermented liquor is cooled and stored cold, centrifuged, filtered, diluted, sterilized, and bottled to obtain the finished product.

[0019] In one embodiment, the segmented mashing process includes:

[0020] First, add xylanase complex to the mashing pot, adjust the pH value of the mash to 5.5 - 5.8, and keep it at 45 - 50 °C for 60 - 90 min for low-temperature protein rest;

[0021] Subsequently, raise the temperature to 63 - 66 °C and keep it for 40 - 80 min;

[0022] Finally, the temperature is raised to 76 - 78 °C and held for 10 - 15 minutes to complete the saccharification process. During the whole saccharification process, stirring is carried out throughout, and the stirring rate is 5 - 10 rpm;

[0023] Among them, the addition amount of the xylan complex enzyme is 0.2 - 0.5 kg / T of wheat malt.

[0024] In one embodiment, in the wort boiling step, the wort boiling time is 60 - 90 minutes, the boiling evaporation rate is 6 - 10%, and the addition amount of hops or hop products is 0.05 - 0.06% of the total mass of the wort.

[0025] In one embodiment, the brewer's yeast is the extra-high gravity beer Lager yeast strain TG - 01, with the preservation number of CGMCC No. 19839, and the taxonomic name is Saccharomyces pastorianus (Pasteur yeast). It was preserved in the General Microbiology Center of the China Committee for Culture Collection of Microorganisms on May 19, 2020, at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing.

[0026] In one embodiment, the fermentation step includes:

[0027] The cooled wort is aerated and inoculated with brewer's yeast, and then put into the fermentation tank. The yeast count at full tank is controlled to be 13 million / ml - 18 million / ml, and fermentation is carried out at the main fermentation temperature of 18 - 20 °C;

[0028] When the diacetyl drops to 0.1 mg / L, it enters the cooling and cold storage process. Among them, the cold storage temperature is -1 - 0 °C, and the cold storage time is more than 7 days.

[0029] Compared with the prior art, the advantages and positive effects of the present invention are as follows:

[0030] 1. The strong beer with rich fruity aroma and its preparation method provided by the present invention can brew a strong beer with rich fruity aroma, strong flavor characteristics and good drinkability on the premise of ensuring normal fermentation, which can meet the special needs of consumers for strong beer. Among them, the original wort concentration of this beer is 28 - 30 °P, the alcohol content ≥ 12.0% vol, and the alcohol - ester ratio is 1.2 - 2.5;

[0031] 2. The strong beer with rich fruity aroma and its preparation method provided by the present invention have the same fermentation cycle as ordinary beer, can complete fermentation within 14 days, have good maturity, low acetaldehyde, and high ester content at the same time;

[0032] 3. The strong beer with rich fruity aroma provided by the present invention and its preparation method solve the production bottleneck that the separation of the whirlpool precipitation coagulum is not complete due to high viscosity in the preparation of 30°P extra-high-concentration wort at present by optimizing the syrup addition process and changing the syrup addition position, and realize industrial production.

[0033] 4. The strong beer with rich fruity aroma provided by the present invention and its preparation method adopt a combination of low pitching yeast number and high-temperature fermentation process to produce flavor substances with high esters and low alcohols in the beer. Finally, the total ester content of the brewed beer is higher than 50mg / L, the higher alcohols are less than 120mg / L, the alcohol-ester ratio is 1.2 - 2.5, and the RDF is between 65 - 68%. The beer body is strong, with rich fruity aroma, mellow, full, coordinated taste and aftertaste. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the difference comparison of the wort viscosities with different wort concentrations provided by the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0036] The embodiment of the present invention provides a strong beer with rich fruity aroma. The beer is prepared by using barley malt, wheat malt and syrup as the main raw materials and fermenting with bottom yeast. The original wort concentration of the beer is 28 - 30°P, the alcohol content is ≥12.0% vol, the alcohol-ester ratio is 1.2 - 2.5, and the RDF is between 65 - 68%.

[0037] In a specific embodiment, the content of total ester substances in the beer is >50mg / L, and the higher alcohols are <120mg / L.

[0038] In a specific embodiment, by weight percentage, the total addition ratio of barley malt and wheat malt is 40 - 50%, and the syrup addition ratio is 50 - 60%.

[0039] In a specific embodiment, by weight percentage, the addition amount of barley malt accounts for 70 - 80% of the total mass of malt, and wheat malt accounts for 20 - 30% of the total mass of malt. Among them, the α-N content of the barley malt is controlled at 140 - 170mg / 100g, and the α-N content of the wheat malt is controlled at 180 - 220mg / 100g.

[0040] In the above embodiment, the α-N content of barley malt and wheat malt is controlled within the above range in order to provide sufficient nitrogen source nutrition for yeast fermentation and ensure normal fermentation requirements.

[0041] In a specific embodiment, the syrup is corn starch syrup or maltose syrup, and the solid content of the syrup is 80%.

[0042] The present invention also provides a method for preparing the strong beer with rich fruity aroma as described in any one of the above embodiments, comprising the following steps:

[0043] S1. Saccharification: Barley malt and wheat malt are selected as the main raw materials, mixed in a ratio of 1:(2.8-3.0) and added into the saccharification pot, and the saccharification process is carried out in stages at 45-78°C;

[0044] S2. Wort filtration: After saccharification is completed, the wort is filtered and the tank is washed to obtain unboiled whole wheat wort;

[0045] S3. Wort boiling: transfer the unboiled whole wheat wort into a boiling pot for boiling, control the boiling time and boiling evaporation rate, and add hops or hop products during the boiling process;

[0046] S4, wort cooling: after the whole wheat wort after boiling is vortexed and precipitated, syrup is added to the wort before the wort is cooled, so that it is fully mixed with the hot wort after vortexing, and then enters the thin plate cooling device to cool the mixed syrup and whole wheat wort to obtain a cooled wort with a pH of 28-30°;

[0047] S5, fermentation: the cooled wort is oxygenated and added with beer yeast, then put into a fermentation tank, and fermented at a main fermentation temperature of 18-20°C to obtain fermented wine;

[0048] S6. Filtration and dilution of wine: The fermented wine is cooled and stored cold, centrifuged, filtered, diluted, sterilized and packaged to obtain the finished product.

[0049] In the above embodiment, a method for preparing a strong beer with rich fruity aroma is provided. The method solves the production bottleneck of incomplete separation of vortex precipitation coagulants due to high viscosity in the current preparation of 30°P ultra-high concentration wort by optimizing the syrup addition process and changing the syrup addition position, solves the problems of residual coagulants adsorbing yeast, affecting yeast fermentation, rough beer taste and increased beer loss, and realizes industrial production; on this basis, by controlling the addition amount of low full tank yeast and combining high temperature fermentation process, the production of high-ester and low-alcohol flavor substances in beer is achieved, the final brewed beer has a total ester content of higher than 50 mg / L, higher alcohols of less than 120 mg / L, an alcohol-ester ratio of 1.2-2.5, and an RDF of between 65-68%. The beer has a strong body, rich fruity aroma, and a mellow, full, coordinated taste with a sweet aftertaste.

[0050] In a specific embodiment, the segmented saccharification process includes:

[0051] First, add xylanase complex to the saccharification pot, adjust the pH value of the mash to 5.5 - 5.8, keep it at 45 - 50 °C, and hold for 60 - 90 min for low-temperature protein rest;

[0052] Subsequently, raise the temperature to 63 - 66 °C and hold for 40 - 80 min;

[0053] Finally, raise the temperature to 76 - 78 °C, hold for 10 - 15 min to complete the saccharification process. During the whole saccharification process, stir continuously, and the stirring rate is 5 - 10 rpm;

[0054] Among them, the addition amount of the xylanase complex is 0.2 - 0.5 kg / T of wheat malt.

[0055] In a specific embodiment, in the wort boiling step, the wort boiling time is 60 - 90 min, the boiling evaporation rate is 6 - 10%, and the addition amount of hops or hop products is 0.05 - 0.06% of the total mass of the wort.

[0056] In a specific embodiment, the brewer's yeast is the extra-high gravity beer Lager yeast strain TG-01, with the preservation number CGMCC No. 19839, and the taxonomic name is Saccharomyces pastorianus (Pasteur yeast). It was deposited in the General Microbiological Center of the China National Culture Collection Center on May 19, 2020, at the address: No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing.

[0057] In a specific embodiment, the fermentation step includes:

[0058] The cooled wort is aerated and inoculated with brewer's yeast, put into the fermentation tank, and the yeast count at full tank is controlled to be 13 million / ml - 18 million / ml, and fermentation is carried out at the main fermentation temperature of 18 - 20 °C;

[0059] When the diacetyl drops to 0.1 mg / L, enter the cooling and cold storage process. Among them, the cold storage temperature is -1 - 0 °C, and the cold storage time is more than 7 days.

[0060] In order to introduce the strong beer with rich fruity aroma and its preparation method provided by the embodiments of the present invention more clearly and in detail, the following will be described in combination with specific embodiments.

[0061] Example 1

[0062] This example provides a preparation method of a strong beer with rich fruity aroma, specifically as follows:

[0063] (1) Raw material crushing: By weight percentage, the proportion of malt used is 40%, and the proportion of auxiliary material syrup used is 60%. In the malt formula, the proportion of barley malt accounts for 60% of the total mass of malt, and the proportion of wheat malt accounts for 40% of the total mass of malt (weight percentage). The α-N index of barley malt is controlled at 150 mg / 100 g, the α-N index of wheat malt is controlled at 220 mg / 100 g, and the total protein content is controlled at 13.0 - 15.0%. The syrup used is corn starch syrup or malt syrup, and its solid content is 75 - 80%;

[0064] (2) Saccharification: The crushed barley malt and wheat malt raw materials are slurried with brewing water (the ratio of material to water is 1:3.0), added to the saccharification pot, and the pH value of the mash is adjusted to 5.5 - 5.8 with lactic acid. Xylanase complex is added, and the addition amount is 0.2 - 0.5 kg / T malt. It is kept at 45°C for 90 min for low-temperature protein rest; then it is heated to the saccharification temperature of 66°C and kept for 40 min; the whole process is stirred throughout, and the stirring rate is 5 - 10 rpm. After that, it is heated to 78°C and kept for 15 min;

[0065] (3) Wort filtration: After passing the iodine test, wort filtration and sparging are carried out to obtain unboiled mixed wort;

[0066] (4) Wort boiling: The mixed wort is transferred to the boiling pot for wort boiling for 45 minutes, and the evaporation rate is controlled at 6%. During the wort boiling process, 0.05% of the wort weight of hops or hop products, such as Qingdao Dahua, Cascade hops, etc., are added;

[0067] (5) Wort cooling: The whole wheat wort after boiling is put into the whirlpool settling tank. After 20 min of whirlpool settling, syrup is added before wort cooling and is fully mixed with the hot wort after whirlpool settling. Then it enters the plate heat exchanger to cool the mixed syrup and whole wheat wort to prepare 30°P cooled wort;

[0068] (6) Fermentation: The cooled wort is filled with pure oxygen into the fermentation tank, and at the same time, a super-high gravity beer yeast strain is added. The fermentation process parameters are controlled as follows: the yeast count at full tank is 15 million / ml, the fermentation temperature is controlled at 18°C. When the diacetyl drops to 0.1 mg / L, it is cooled to 0°C for cold storage. Among them, the super-high gravity beer yeast strain is the super-high gravity beer Lager yeast strain TG-01, and its preservation number is CGMCC No. 19839. Its taxonomic name is Saccharomyces pastorianus (Pasteur yeast), and it was preserved in the China General Microbiological Culture Collection Center on May 19, 2020, at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing;

[0069] (7) Filtration and dilution of the liquor: The liquor obtained from fermentation is cold stored at 0°C for more than 7 days, centrifuged to remove the yeast remaining in the fermentation broth, and the centrifuged liquor is filtered through diatomaceous earth, clarified liquor and other processes, and then filled, sterilized and sub-packed to obtain the finished product.

[0070] Example 2

[0071] This example provides a method for preparing a strong beer with rich fruity aroma, specifically as follows:

[0072] (1) Raw material crushing: By weight percentage, the usage ratio of malt is 50%, and the usage ratio of auxiliary material syrup is 50%. In the malt formula, the proportion of barley malt accounts for 80% of the total mass of malt, and the proportion of wheat malt accounts for 20% of the total mass of malt (by weight percentage). The α-N index of barley malt is controlled at 160 mg / 100 g, and the α-N index of wheat malt is controlled at 210 mg / 100 g. The syrup used is corn starch syrup or malt syrup, and its solid content is 80%;

[0073] (2) Saccharification: The crushed barley malt and wheat malt raw materials are slurried with brewing water (the ratio of material to water is 1:3.0), added to the saccharification pot, the pH value of the mash is adjusted to 5.5 - 5.8 with lactic acid, xylanase complex is added, and the addition amount is 0.2 - 0.5 kg / T malt. It is kept warm at 50°C for 60 min for low-temperature protein rest; then it is heated to the saccharification temperature of 66°C and kept warm for 60 min; the whole process is stirred throughout, and the stirring rate is 5 - 10 rpm. After that, it is heated to 78°C and kept warm for 10 min;

[0074] (3) Wort filtration: After the iodine test is qualified, wort filtration and sparging are carried out to obtain the unboiled mixed wort;

[0075] (4) Wort boiling: The mixed wort is transferred to the boiling pot for wort boiling for 60 minutes, and the evaporation rate is controlled at 8%. During the wort boiling process, 0.06% of the wort weight of hops or hop products, such as Qingdao Dahua, Cascade hops, etc., are added;

[0076] (5) Wort cooling: The whole wheat wort after boiling is put into the whirlpool settling tank. After 20 min of whirlpool settling, syrup is added before wort cooling and is fully mixed with the hot wort after whirlpool settling, and then enters the plate heat exchanger to cool the mixed syrup and whole wheat wort to prepare 30°P cooled wort;

[0077] (6) Fermentation: The cooled wort is filled with pure oxygen into the fermentation tank, and at the same time, a super-high-gravity beer yeast strain is added. The fermentation process parameters are controlled as follows: the yeast count at the start of fermentation is 18 million / ml, the fermentation temperature is controlled at 18 °C. When the diacetyl content drops to 0.1 mg / L, the temperature is lowered to 0 °C for cold storage. Among them, the super-high-gravity beer yeast strain is the super-high-gravity beer Lager yeast strain TG-01, with the preservation number of CGMCC No. 19839, and the taxonomic name is Saccharomyces pastorianus. It was preserved in the General Microbiological Center of the China Committee for Culture Collection of Microorganisms on May 19, 2020, at No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing;

[0078] (7) Filtration and dilution of the liquor: The liquor obtained from fermentation is cold-stored at 0 °C for more than 7 days, and the yeast remaining in the fermentation broth is removed by centrifugation. After centrifugation, the liquor is filtered through diatomaceous earth, clarified, and then filled, sterilized, and sub-packaged to obtain the finished product.

[0079] Example 3

[0080] This example provides a method for preparing a strong beer with a rich fruity aroma, specifically as follows:

[0081] (1) Raw material crushing: By weight percentage, the usage ratio of malt is 45%, and the usage ratio of the auxiliary material syrup is 55%. In the malt formula, the proportion of barley malt accounts for 70% of the total mass of malt, and the proportion of wheat malt accounts for 30% of the total mass of malt (by weight percentage). The α-N index of barley malt is controlled at 150 mg / 100 g, and the α-N index of wheat malt is controlled at 220 mg / 100 g. The syrup used is corn starch syrup or malt syrup, with a solid content of 80%;

[0082] (2) Saccharification: The crushed barley malt and wheat malt raw materials are slurried with brewing water (the ratio of material to water is 1:2.8), added to the saccharification pot, and the pH value of the mash is adjusted to 5.5 - 5.8 with lactic acid. Xylanase complex is added, and the addition amount is 0.2 - 0.5 kg / T malt. It is kept at 50 °C for 90 min for low-temperature protein rest; then the temperature is raised to the saccharification temperature of 65 °C and kept for 60 min; the whole process is stirred throughout, and the stirring rate is 5 - 10 rpm. After that, the temperature is raised to 78 °C and kept for 15 min;

[0083] (3) Wort filtration: After passing the iodine test, wort filtration and sparging are carried out to obtain the unboiled mixed wort;

[0084] (4) Wort boiling: The mixed wort is transferred to the boiling pot for wort boiling for 75 minutes, and the evaporation rate is controlled at 10%. During the wort boiling process, 0.06% of the wort weight of hops or hop products, such as Qingdao Dahua, Cascade hops, etc., are added;

[0085] (5) Wort cooling: The whole wheat wort after boiling is put into a whirlpool sedimentation tank. After 20 minutes of whirlpool sedimentation, syrup is added before wort cooling and is fully mixed with the hot wort after whirlpool sedimentation, and then enters a thin plate cooling device to cool the mixed syrup and whole wheat wort to prepare a 30°P cooled wort;

[0086] (6) Fermentation: The cooled wort is filled with pure oxygen into a fermentation tank, and at the same time, a super-high gravity beer yeast strain is added. The fermentation process parameters are controlled as follows: the yeast count at full tank is 15 million / ml, the fermentation temperature is controlled at 20°C. When the diacetyl drops to 0.1 mg / L, the temperature is lowered to 0°C for cold storage. Among them, the super-high gravity beer yeast strain is the super-high gravity beer Lager yeast strain TG-01, and its preservation number is CGMCC No. 19839. Its taxonomic name is Saccharomyces pastorianus, and it was preserved in the General Microbiology Center of the China Committee for Culture Collection of Microorganisms on May 19, 2020, at the address: No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing;

[0087] (7) Wine filtration and dilution: The wine obtained from fermentation is cold stored at 0°C for more than 7 days, and the yeast remaining in the fermentation broth is removed by centrifugation. After centrifugation, the wine is filtered through diatomaceous earth, clarified wine and other processes, and then filled, sterilized and sub-packed to obtain the finished product.

[0088] Comparative Example 1

[0089] This comparative example provides a conventional beer preparation method, specifically:

[0090] Its preparation method is the same as that of Example 1, except that the syrup addition position is directly added to the boiling pot.

[0091] Syrup addition position screening test

[0092] The present invention discovers by comparing the differences in the viscosities of worts with different concentrations (the results are as Figure 1 shown) that when the syrup addition position as shown in Comparative Example 1 (i.e., directly added to the boiling pot) is adopted, when the wort concentration is 30°P, the viscosity is 4.2 Mpas. Compared with the viscosity of 20°P wort, the viscosity increases by 83%. According to Stokes' sedimentation formula, due to the increase in wort viscosity, the coagulants generated during boiling are suspended in the wort and are not easily sedimented, resulting in incomplete separation of the coagulants in the whirlpool sedimentation and poor whirlpool sedimentation effect. Thus, it can be seen that as the concentration of the prepared wort increases, the wort viscosity increases. The traditional method of adding syrup to the boiling pot greatly limits the whirlpool sedimentation effect of the wort, and the traditional syrup addition position cannot meet the needs of the present invention for preparing super-high concentration wort. In order to completely solve this problem, it is necessary to first optimize the syrup addition position to solve the technical problem of poor whirlpool sedimentation effect mentioned above.

[0093] Based on the above analysis, the present invention attempts to change the position of syrup addition, and finally selects to add syrup before wort cooling, fully mix it with the hot wort after whirlpool precipitation, and then enter the thin plate cooling device to cool the mixed syrup and whole wheat wort, and prepare 30°P cooled wort, which solves the production bottleneck that the separation of the coagulum in whirlpool precipitation is not thorough due to high viscosity in the preparation of 30°P extra-high gravity wort at present, and realizes industrial production.

[0094] Screening test of yeast inoculation amount and fermentation temperature

[0095] The purpose of this experiment is to optimize the 30°P extra-high gravity fermentation process by studying the metabolic rules of key extra-high gravity fermentation process parameters on sugar reduction, flavors such as alcohols and esters. The specific experimental process and results are as follows:

[0096] (1) Experimental conditions:

[0097] Yeast strain: TG-01;

[0098] Fermented wort: 13°P whole wheat wort, add syrup to make it into 30°P extra-high gravity wort, add yeast extract powder to control the a-N content of the wort above 300 mg / L;

[0099] Fermentation process: Select 500 ml fermentation bottles, add 300 ml of 30°P extra-high gravity wort to the fermentation bottles, conduct fermentation experiments according to the following designed test plan, and measure and count the physical and chemical parameters such as the total alcohol, total ester content and alcohol-ester ratio in the obtained fermented liquor:

[0100] Table 1 Test plan for the influence of process parameters on alcohols, esters and fermentation rate

[0101]

[0102] As can be seen from the above table, this DOE design experiment sets two factors and two levels with 2 central points, among which the inoculation amount (15 million / ml, 35 million / ml), fermentation temperature (14 °C, 20 °C), central point (inoculation amount 25 million, fermentation temperature 17 °C). According to the DOE test data analysis in Table 1, both the inoculation amount and the fermentation temperature have a significant impact on sugar reduction, while the fermentation temperature has a significant impact on the formation of esters. Therefore, low inoculation amount and high-temperature fermentation are beneficial to the formation of a fermentation flavor with rich fruity aroma. Considering the change rules of alcohols and esters and normal fermentation, a verification experiment is carried out on the process parameters of an inoculation amount of 15 million / ml and a fermentation temperature of 18 °C. The results conform to the change rules of flavor substances, and the alcohol-ester ratio is controlled at about 2.0 and meets the requirements of brewing sugar reduction.

[0103] Comparison test of high-temperature and low-temperature fermentation processes

[0104] In this experiment, the differences in various physical and chemical parameters of the wine liquors prepared by two fermentation methods, namely high-temperature primary fermentation and low-temperature primary fermentation, were also compared, so as to optimize a fermentation method more suitable for the present invention. The specific experimental process and result analysis are as follows:

[0105] (1) The fermentation process is shown in Table 2:

[0106] Table 2 Fermentation processes of high-temperature primary fermentation and low-temperature primary fermentation

[0107]

[0108]

[0109] (2) Test results:

[0110] Table 3 Comparison of conventional indexes of cold-stored wines obtained by high-temperature primary fermentation and low-temperature primary fermentation processes

[0111]

[0112] Table 4 Comparison of maturity and flavor indexes of cold-stored wines obtained by high-temperature primary fermentation and low-temperature primary fermentation processes

[0113]

[0114]

[0115] Table 5 Sensory evaluation of cold-stored wines obtained by high-temperature primary fermentation and low-temperature primary fermentation processes

[0116]

[0117] As can be seen from the above tables, compared with low-temperature primary fermentation, the method of high-temperature primary fermentation adopted in the present invention finally obtains a strong-type beer with good maturity, low acetaldehyde, high ester content, and its fermentation cycle is the same as that of ordinary beer, and the fermentation can be completed within 14 days. This method combines a low yeast number addition at full tank and a high-temperature fermentation process to achieve the production of flavor substances with high esters and low alcohols in beer. Finally, the total ester content of the brewed beer is higher than 50 mg / L, the higher alcohols are less than 120 mg / L, the alcohol-ester ratio is 1.2 - 2.5, and the RDF is between 65 - 68%. The wine body is strong, with a rich fruity aroma, a mellow, full, harmonious and sweet aftertaste.

Claims

1. A method for preparing a strong beer with a rich fruity aroma, characterized in that, It includes the following steps: Saccharification: Selecting barley malt and wheat malt as the main raw materials, mixing them in a ratio of material to water of 1:(2.8 - 3.0) and adding them to a saccharification pot, and performing a segmented saccharification process at 45 - 78°C. Among them, by weight percentage, the total addition ratio of barley malt and wheat malt is 40 - 50%, and the α-N content of the barley malt is controlled at 140 - 170 mg / 100 g, and the α-N content of the wheat malt is controlled at 180 - 220 mg / 100 g; Wort filtration: After saccharification is completed, when the iodine test is qualified, perform wort filtration and sparging to obtain unboiled whole wheat wort; Wort boiling: Transfer the unboiled whole wheat wort to a boiling pot for boiling, control the boiling time and boiling evaporation rate, and add hops or hop products during the boiling process; Wort cooling: After the boiling of the whole wheat wort is completed, add syrup during the wort cooling process after whirlpool precipitation and before wort cooling, so that it is fully mixed with the hot wort after whirlpool precipitation, and then enter a thin plate cooling device to cool the mixed syrup and whole wheat wort to obtain cooled wort with a concentration of 28 - 30°P. Among them, by weight percentage, the syrup addition ratio is 50 - 60%; Fermentation: The cooled wort is aerated and inoculated with brewer's yeast, and then put into a fermentation tank. The yeast count at the full tank is controlled to be 13 million / ml - 18 million / ml, and fermentation is carried out at the main fermentation temperature of 18 - 20°C to obtain the fermented liquor. Among them, the brewer's yeast is the extra-high gravity beer Lager yeast strain TG-01, with the preservation number of CGMCC No. 19839, and the taxonomic name is Saccharomyces pastorianus , which was deposited at the General Microbiology Center of the China General Microbiological Culture Collection Center on May 19, 2020, at the address of No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing; Beer filtration and dilution: Cool and store the fermented beer liquid at a reduced temperature, centrifuge, filter, dilute, sterilize, and package it to obtain the finished beer. Among them, the original wort concentration of the beer is 28 - 30°P, the alcohol content is ≥12.0% vol, the alcohol-ester ratio is 1.2 - 2.5, and the RDF is between 65 - 68%.

2. The preparation method of the strong-type beer with rich fruity aroma according to claim 1, characterized in that, The total ester content in the beer is >50 mg / L, and the higher alcohols are <120 mg / L.

3. The preparation method of the strong beer with rich fruity aroma according to claim 1, characterized in that, By weight percentage, the addition amount of barley malt accounts for 70 - 80% of the total mass of malt, and the wheat malt accounts for 20 - 30% of the total mass of malt.

4. The preparation method of the strong-type beer with rich fruit aroma according to claim 1, characterized in that, The syrup is corn starch syrup or malt syrup, and its solid content is 80%.

5. The preparation method of the strong beer with rich fruit aroma according to claim 1, characterized in that, The segmented saccharification process includes: First, add xylanase complex to the saccharification pot, adjust the pH value of the mash to 5.5 - 5.8, and keep it at 45 - 50°C for 60 - 90 min for low-temperature protein rest; Subsequently, raise the temperature to 63 - 66°C and keep it for 40 - 80 min; Finally, raise the temperature to 76 - 78°C, keep it for 10 - 15 min to complete the saccharification process. During the whole saccharification process, stir constantly, and the stirring rate is 5 - 10 rpm; Among them, the addition amount of the xylanase complex is 0.2 - 0.5 kg / T of wheat malt.

6. The preparation method of the strong-type beer with rich fruit aroma according to claim 1, characterized in that, In the wort boiling step, the wort boiling time is 60 - 90 min, the boiling evaporation rate is 6 - 10%, and the addition amount of hops or hop products is 0.05 - 0.06% of the total mass of wort.

7. The preparation method of the strong beer with rich fruity aroma according to claim 1, characterized in that, The fermentation step includes: The cooled wort is aerated and inoculated with brewer's yeast, put into a fermentation tank, and fermented at a main fermentation temperature of 18 - 20°C; When the diacetyl drops to 0.1 mg / L, enter the process of cooling and cold storage. Among them, the cold storage temperature is -1 - 0°C, and the cold storage time is more than 7 days.

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