Juice and wort co-fermentation technology for brewing vitis heyneana craft beer

Abstract

A fruit juice and wort co-fermentation technology for brewing craft downy grape beer relates to the field of beer brewing, and comprises the following steps: 1) crushing malt; (2) saccharifying maltose; (3) filtering and washing grains; (4) wort boiling: adding secondary humulus lupulus during boiling; 5) rotational precipitation of wort; (6) cooling the wort and feeding into a tank; and 7) fermentation: inoculating the wheat juice with the activated yeast for fermentation, including main fermentation, diacetyl reduction, cooling precipitation, secondary fermentation and cold storage after-ripening, and adding the vitis heyneana juice in the main fermentation stage for co-fermentation with the wheat juice. The vitis heyneana juice is applied to the craft beer, the research of vitis heyneana in the field of food processing is enriched, and the drinkability and redrinkability of the craft beer are improved. According to the method, the process conditions such as the addition time and addition amount of the vitis heyneana juice, the concentration of the set wort and the addition amount of the hops are determined, the co-fermentation technology of the juice and the wort is determined, an appropriate scheme is provided for the craft vitis heyneana beer, and the market of the craft vitis heyneana beer is beneficially developed.

Description

Technical Field

[0001] The present invention relates to the field of beer brewing, and particularly to a co-fermentation technology of fruit juice and wort for brewing fine wine made from Vitis heyneana Roem. et Schult. Background Art

[0002] Most fruits are not easy to preserve and store, and the deep processing capacity and utilization rate of fruits are relatively low. During the season when fruits are on the market in large quantities, many fresh fruits that cannot be sold in time can only rot, which is likely to damage the vital interests of fruit farmers. Fruit fine wine beer, which combines the flavors of fruits and fine wine beer, has a unique taste and rich nutrition, and is deeply loved by consumers. It is one of the main development directions in the fine wine beer industry in recent years. Studying fruit fine wine beer is a brand-new path for the development of fruit deep processing, exploring the research of fruits in the food processing field, and enhancing the confidence of fruit farmers.

[0003] However, there are still some problems in the existing fruit fine wine beer brewing technology, which limit its market potential and consumer experience. During the brewing process, the addition time and amount of fruit juice lack scientificity and systematicness, resulting in the inability to coordinate and integrate the fruit flavor and the taste of beer, and even may produce adverse chemical reactions, affecting the overall flavor of beer. In addition, the current brewing process of fruit fine wine beer is relatively traditional and lacks innovation, and most of the existing products are limited to common fruit varieties. At present, the application research of Vitis heyneana Roem. et Schult. in beer brewing is not sufficient. The original juice of Vitis heyneana Roem. et Schult. contains more organic acids and has a high acidity, so it is necessary to adjust the base wine process formula and explore how to perfectly integrate Vitis heyneana Roem. et Schult. juice and fine wine beer through scientific research methods. Summary of the Invention

[0004] The purpose of the present invention is to solve the above problems in the prior art, and provide a co-fermentation technology of fruit juice and wort for brewing fine wine made from Vitis heyneana Roem. et Schult., to provide a suitable brewing scheme for fine wine made from Vitis heyneana Roem. et Schult., enrich the research of Vitis heyneana Roem. et Schult. in the food processing field, and further explore the fruit fine wine beer market.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions:

[0006] A co-fermentation technology of fruit juice and wort for brewing fine wine made from Vitis heyneana Roem. et Schult. includes the following steps:

[0007] 1) Malt crushing: Weigh an appropriate amount of malt and crush it into particles the size of a pen tip, requiring the malt husk to be broken but not crushed;

[0008] 2) Malt saccharification: Add an appropriate amount of water and crushed malt to the saccharification tank, and perform step-by-step saccharification by raising the temperature in a stepped manner to obtain a mixed liquid;

[0009] 3) Filtration and sparging: After saccharification is completed, the wort is pumped into the boiling kettle, and then hot water is evenly sprinkled on the spent grain layer for sparging. The wort obtained from sparging is also pumped into the boiling kettle.

[0010] 4) Wort boiling: Heat the wort to boiling, and add hops twice during the boiling period.

[0011] 5) Wort whirlpool settling: Pump the boiled wort into the whirlpool tank. The wort enters the whirlpool tank through the side opening and settles. After settling, it is left standing. The hot coagulum of the wort aggregates at the bottom of the whirlpool tank under the action of centrifugal force, and the clarified wort is introduced into the fermentation bottle through the outlet at the bottom.

[0012] 6) Wort cooling and tank entry: Pump the clarified wort into the fermentation bottle and quickly cool the wort.

[0013] 7) Fermentation: Inoculate the activated yeast into the wort for fermentation. The fermentation is divided into five stages, namely primary fermentation, diacetyl reduction, cooling and precipitation, secondary fermentation, and cold storage and ripening in sequence, and muscat grape juice is added in the primary fermentation stage.

[0014] In step 1) malt crushing, the malt is pilsner malt and munich malt with a mass ratio of 9 - 10:1.

[0015] In step 2) malt saccharification, the water - to - malt mass ratio of water volume to malt mass is 3.0 - 5.0 L / kg.

[0016] In step 2) malt saccharification, the step - by - step temperature - rising fractional saccharification includes: First step, add water and heat to 68 - 70 °C, add the crushed malt and stir evenly; Second step, keep the temperature at 68 - 70 °C for 58 - 62 min; Third step, raise the temperature to 70 - 74 °C and keep it until the iodine test shows no change; Fourth step, raise the temperature to 76 - 80 °C and keep it for 8 - 12 min for enzyme inactivation.

[0017] In step 4) wort boiling, the total boiling time is 58 - 62 min, and the hop addition amount is 0.9 - 1.5 g / L of wort; Add the first hops at the beginning of boiling, and the added hops are chinook hops, with a weight accounting for 42% - 44% of the total hop addition amount; Add a mixture of chinook and fuggle hops 4 - 5 min before the end of boiling, with each added according to 28% - 29% of the total hop addition amount.

[0018] In step 6) wort cooling and tank entry, the final wort concentration is 10 - 14 °P.

[0019] In step 7) fermentation: The yeast inoculation temperature is 18 - 20 °C.

[0020] Step 7) The fermentation is divided into five stages: The first stage is the main fermentation, which lasts for 5 - 7 days at a fermentation temperature of 19 - 20°C; the Vitis heyneana juice is added at 24 hours during the main fermentation, and the addition amount of the Vitis heyneana juice is 23% - 25% of the volume of the wort. After that, the juice and the wort are co-fermented; the second stage is the ripening stage for the reduction of diacetyl, with a fermentation temperature of 21 - 22°C for 3 - 4 days; the third stage is the cooling and precipitation stage, with a fermentation temperature of 3 - 4°C for 36 - 60 hours; the fourth stage is the secondary fermentation stage. The upper clear wine after cold precipitation is transferred to a brown glass bottle, white granulated sugar is added, and it is placed in a constant temperature incubator at 24 - 26°C for secondary fermentation for 4 - 6 days; the fifth stage is the cold storage and ripening stage, and the beer after secondary fermentation is placed in a 4°C refrigerator for ripening for 12 - 14 days.

[0021] A Vitis heyneana craft beer is brewed by using the described co-fermentation technology of fruit juice and wort.

[0022] Compared with the prior art, the beneficial effects achieved by the technical solution of the present invention are:

[0023] Through the specific co-fermentation process parameters of fruit juice and wort for Vitis heyneana craft beer, the present invention provides an ideal solution for the production of craft beer with a strong Vitis heyneana flavor and significant nutritional and health care effects. The implementation of this invention not only effectively solves the technical problems encountered in the current brewing of fruit juice craft beer, but also brings a new choice of novel, unique, delicious and healthy beverage for consumers. This innovation not only broadens the market field of fruit juice craft beer, but also promotes the diversified utilization of fruit resources and provides a broader sales outlet for seasonal fruits. Description of the Drawings

[0024] Figure 1 Effect of the addition time of Vitis heyneana juice on alcohol content;

[0025] Figure 2 Effect of the addition time of Vitis heyneana juice on total acid;

[0026] Figure 3 Effect of the addition time of Vitis heyneana juice on turbidity;

[0027] Figure 4 Effect of the addition amount of Vitis heyneana juice on alcohol content;

[0028] Figure 5 Effect of the addition amount of Vitis heyneana juice on total acid;

[0029] Figure 6 Effect of the addition amount of Vitis heyneana juice on turbidity;

[0030] Figure 7 Effect of the final wort concentration on alcohol content;

[0031] Figure 8 To determine the effect of wort concentration on total acidity;

[0032] Figure 9 To determine the effect of wort concentration on turbidity;

[0033] Figure 10 The effect of hop addition on alcohol content;

[0034] Figure 11 The effect of hop addition on total acidity;

[0035] Figure 12 The effect of hop addition on turbidity. DETAILED DESCRIPTION

[0036] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer and understandable, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments, but the scope of the present invention is not limited by these embodiments. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and the following embodiments are only used to illustrate the principles of the present invention, and the various processes and methods not described in detail are conventional methods known in the art. It should be understood that these embodiments are only for illustrating the present invention, and are not intended to limit the scope of the present invention in any way.

[0037] Vitis pubescens is a woody vine plant of the subgenus Eugrana in the genus Vitis of the family Vitaceae. It is native to China and is mainly distributed in Guangxi Zhuang Autonomous Region, Guizhou Province, Shanxi Province, Gansu Province and other places in China. It is the most widely distributed wild grape species in my country and the most widely distributed and densely planted grape species in Guangxi. Vitis pubescens has thick skin and thin flesh, and the flesh and skin are easy to separate. It has high acidity but low sugar content, so the experience of direct consumption is not good, but the processing characteristics are good. Vitis pubescens tastes sweet, sour, slightly bitter, and has a flat nature. The whole plant can be used and has good medicinal value. Vitis pubescens is rich in 18 kinds of amino acids, multiple vitamins, and trace elements. Eating it in moderation can supplement the nutrients needed by the body; it is rich in dietary fiber, which can promote gastrointestinal motility and help digestion and absorption of food; it is rich in anthocyanins, flavonoids, polyphenols and other antioxidant substances.

[0038] The Vitis heyneana Roem. et Schult. used in the present invention is from Luocheng Mulao Autonomous County, Guangxi Zhuang Autonomous Region. Luocheng Mulao Autonomous County is one of the origin places of Vitis heyneana Roem. et Schult. and has rich resources of Vitis heyneana Roem. et Schult. In recent years, the fresh fruit yield of Vitis heyneana Roem. et Schult. in Luocheng Mulao Autonomous County has increased rapidly. Due to the unstable sales volume, it is difficult for local enterprises related to the processing of Vitis heyneana Roem. et Schult. to purchase a large amount of fresh fruits of Vitis heyneana Roem. et Schult., and the fresh fruits of Vitis heyneana Roem. et Schult. are prone to unsalable. How to expand the industrial chain of Vitis heyneana Roem. et Schult. and increase the sales volume of related products to help farmers consume the fresh fruits is a huge challenge faced by Luocheng Mulao Autonomous County. The present invention explores the influence of various factors on the physicochemical properties and sensory evaluation of Vitis heyneana Roem. et Schult. craft beer, determines the juice-wort co-fermentation process conditions of Vitis heyneana Roem. et Schult. craft beer, finds the most suitable plan for brewing Vitis heyneana Roem. et Schult. flavored beer, and develops a unique Vitis heyneana Roem. et Schult. craft beer to promote the economic development of Luocheng Mulao Autonomous County.

[0039] Example 1

[0040] A processing technology of Vitis heyneana Roem. et Schult. craft beer comprises the following steps:

[0041] S1. Malt crushing: Weigh 90 g of Pilsner malt and 10 g of Munich malt, and crush them into particles the size of a pen tip, requiring the malt husks to be broken but not crushed.

[0042] S2. Malt saccharification: Add 300 mL of water to the saccharification tank, heat it to 68 - 70 °C, then add the crushed malt and stir evenly. Keep the mash at 68 - 70 °C for 58 - 62 min, then raise the temperature to 70 - 74 °C, keep it until the iodine test shows no change in color, then raise the temperature to 76 - 80 °C, keep it for 8 - 12 min for enzyme inactivation to obtain a mixed liquid.

[0043] S3. Filtration and sparging: After the saccharification is completed, pump the wort to the boiling tank through a wort pump, and then evenly sprinkle 200 mL of hot water at 78 °C on the spent grain layer for sparging. Pump the wort obtained from sparging to the boiling tank together.

[0044] S4. Wort boiling: Heat the wort to boiling, and the total boiling time is 58 - 62 min. Add secondary hops during the boiling process, and the hop addition amount is 1 g / L; add it for the first time when boiling, and the hop added is Chinook, and its weight accounts for 43% of the total hop addition amount; add a mixed hop of Chinook and Fuggle for the second time 4 - 5 min before the end of boiling, and each accounts for 28.5% of the total hop addition amount. After the boiling is completed, 350 mL of wort is obtained in total.

[0045] S5, Wort whirlpool settling: The boiled wort is pumped into the whirlpool tank. The wort enters the whirlpool tank through the side opening, forming a tangential flow, causing the wort to rotate inside the whirlpool tank. After settling for 20 min, the bottom of the whirlpool tank has a lower conical bottom with a slope of 2% at the outlet. The hot coagulum of the wort accumulates at the bottom of the whirlpool tank under the action of centrifugal force. The clarified wort is introduced into the fermentation bottle through the bottom outlet to obtain 300 mL of wort.

[0046] S6, Wort cooling and tank entry: The final wort concentration is 14°P. After the wort is pumped into the fermentation bottle, it is quickly cooled to 18°C with tap water and yeast is inoculated.

[0047] S7, Fermentation: The fermentation is divided into five stages. The first stage is the main fermentation, with a main fermentation time of 5 - 7 days and a fermentation temperature of 19 - 20°C during this stage. The muscat grape juice is added at 24 h during the main fermentation, and the addition amount of the muscat grape juice is 25% of the wort volume. After that, the juice and the wort are co-fermented. The second stage is the post-ripening stage for the reduction of diacetyl, with a fermentation temperature of 21 - 22°C and a fermentation time of 3 - 4 days. The third stage is the cold settling stage, with a fermentation temperature of 3 - 4°C and a time of 36 - 60 h. The fourth stage is the secondary fermentation stage. The upper clear wine after cold settling is transferred to a brown glass bottle, 2 g of granulated sugar is added, and it is placed in a constant temperature incubator at 24 - 26°C for secondary fermentation for 4 - 6 days. The fifth stage is the cold storage stage. The beer after secondary fermentation is put into a 4°C refrigerator for after-ripening for 12 - 14 days.

[0048] Example 2

[0049] In Example 1, the muscat grape juice in step S7 is added at 24 h during the main fermentation. The difference between this example and Example 1 is that the addition times of the muscat grape juice are respectively when the sugar content drops to half, at the start of the post-fermentation, and at the end of the cold settling.

[0050] Example 3

[0051] In Example 1, the addition amount of the muscat grape juice in step S7 is 25% of the wort volume. The difference between this example and Example 1 is that the addition amounts of the muscat grape juice respectively account for .

[0052] Example 4

[0053] In Example 1, the final wort concentration in step S6 is 14°P. The difference between this example and Example 1 is that the final wort concentrations are respectively .

[0054] Example 5

[0055] In Example 1, the addition amount of hops in step S4 is 1 g / L. The difference between this example and Example 1 is that the addition amounts of hops are respectively .

[0056] Example 6

[0057] The difference between this example and Example 1 is that:

[0058] S7, the addition amount of Vitis heyneana juice, S6, the concentration of final wort, S4, the addition amount of hops: Three factors and three levels are adopted , and taking the sensory evaluation score as the standard, the best juice-wort co-fermentation process parameters of Vitis heyneana craft beer are determined. The factor levels are shown in Table 1.

[0059] Table 1 Orthogonal experimental factor level table of juice-wort co-fermentation process parameters for Vitis heyneana craft beer

[0060]

[0061] Index determination

[0062] Determination of alcohol content: Referring to GB / T4928-2008 "Beer Analysis Method", the alcohol content of the obtained Vitis heyneana craft beer was determined by high performance liquid chromatography. After the sample was degassed by ultrasound and then centrifuged, the supernatant was taken and filtered through a 0.45μm filter membrane for standby. The detection conditions were: the chromatographic column model was HP-1011; the injection volume was 20μL; the column temperature was 35°C; the detector temperature was 35°C; the mobile phase was 5mmol / L sulfuric acid solution; the flow rate was 0.6mL / min; the detector was an RI detector. The retention time of the ethanol standard was 20.719min, and the standard curve was .

[0063] Determination of total acid: The total acid content of the sample was determined by the indicator method in GB / T4928-2008. Add 100.0mL of water to a 250mL conical flask, heat to boiling, keep for 2min, then add 10.0mL of degassed beer, continue to heat for 1min, and make the solution boil again within the last 30s, then quickly take it out and cool naturally for 5min, and then quickly rinse the outer wall of the conical flask with tap water to quickly cool the solution to room temperature. Add 0.5mL of phenolphthalein solution and titrate with 0.1mol / L sodium hydroxide solution until the solution turns light pink, which is the titration end point, and record the volume of sodium hydroxide solution consumed. The total acid content of the sample (that is, the number of milliliters of 1.0mol / L sodium hydroxide standard titrant consumed by 100mL of the sample) was calculated according to the formula:

[0064]

[0065] Where:

[0066] X—the total acid content of the sample (mL / 100mL);

[0067] — Concentration of the sodium hydroxide standard titrant (mol / L);

[0068] — Volume of the sodium hydroxide standard titrant consumed (mL);

[0069] 10 — Coefficient for converting to 100 mL of the sample.

[0070] Determination of turbidity: Measure the turbidity of the beer sample using a turbidimeter. First, calibrate the instrument with a standard turbidity solution. After calibration, add the degassed but unfiltered beer sample to the sample bottle. The sample temperature is , shake well, and place it in the turbidimeter for reading.

[0071] Sensory evaluation of Vitis heyneana var. romanetii craft beer: When conducting the sensory evaluation of beer, first assign a coded number to the sample and keep it at a constant temperature of 12 - 15 °C. Then, pour the sample into clean and dry beer tasting glasses at the same height (3 cm from the cup mouth) and at the same pouring speed. Next, invite several professional beer tasters to observe, evaluate, and score the appearance, aroma, taste, and mouthfeel according to the scoring table. The sensory evaluation criteria for Vitis heyneana var. romanetii craft beer are shown in Table 2.

[0072] Table 2 Sensory evaluation criteria for Vitis heyneana var. romanetii craft beer

[0073]

[0074] Note: This sensory evaluation criteria table is designed and modified by referring to the scoring items and score design of the BJCP scoring table, combining the scoring rules of fruit beer and the fruit characteristics of Vitis heyneana var. romanetii.

[0075] Test result 1

[0076] The test results of Example 1 and Example 2 are listed as follows:

[0077] Determine the alcohol content of the beer. The results Figure 1 are shown that when adding Vitis heyneana var. romanetii juice during the main fermentation to 24 h, when the sugar content drops to half, and during the post-fermentation, the alcohol content of the finished beer changes little, and the yeast in the fermentation stage can fully utilize the fermentable sugars in the Vitis heyneana var. romanetii juice. However, adding Vitis heyneana var. romanetii juice during the cold storage stage will cause the alcohol content of the beer to decrease. At this time, most of the yeast has been removed from the beer body, and in an environment below 4 °C, the yeast is in a dormant state, and the fermentable sugars in the Vitis heyneana var. romanetii juice will not be utilized by the yeast but remain in the wine.

[0078] Determine the total acid content of the beer. The results Figure 2As shown in the figure, the later the tricholoma juice is added, the higher the total acid content of the finished beer. The total acid content of tricholoma juice is higher than that of wort. Adding tricholoma juice will increase the total acid content of wort, while the increase in the total acid content of wort will have a negative effect on the total acid content of beer. The higher the total acid content of wort, the less acid produced by yeast fermentation. Yeast secretes organic acids mainly in the stage of vigorous fermentation. When the main fermentation reaches 24h, the yeast starts fermentation soon. At this time, adding tricholoma juice will lead to an increase in the total acid of wort, thereby inhibiting yeast acid production. The later the tricholoma juice is added, the weaker the inhibitory effect on yeast acid production. When tricholoma juice is added during the cold storage stage, the total acid content is the highest, reaching 5.77mL / 100mL.

[0079] Determination of beer turbidity, results Figure 3 As shown in the figure, with the change of the time of adding tricholoma juice, the turbidity of beer does not change much, and the maximum difference is only 1.77EBC. When adding tricholoma juice during cold storage, the fine particles in the tricholoma juice will settle to the bottom of the fermentation bottle and be easily disturbed and re-suspended in the beer. When adding tricholoma juice at other time periods, the yeast flocculation and sedimentation will also drive the suspended matter in the beer to settle to the bottom of the fermentation bottle, forming a relatively solid sludge, which will be discarded after the cold sedimentation stage, and no sediment will appear in the beer.

[0080] The sensory evaluation method was used to score the hairy grape craft beer. The results are shown in Table 3. The time of adding hairy grape juice has a great influence on the sensory score of beer. When hairy grape juice is added at 24h of the main fermentation and during the cold storage stage, the finished beer scores are higher, 84 points and 82 points respectively. When hairy grape juice is added at 24h of the main fermentation, the beer body is clear and brown-yellow, with a strong hairy grape flavor, harmoniously blended with beer, pure taste, moderate acidity, and a strong killing feeling. When hairy grape juice is added when the sugar content drops to half and during post-fermentation, the hairy grape has a strong fruity aroma, but the acidity is slightly high, and the drinking experience is poor. When hairy grape juice is added during cold storage, the acidity is moderate, because the sugar in the juice is not fermented into alcohol, which neutralizes part of the fruit acid taste. Although the sensory experience is good, the hairy grape fruit aroma masks the taste of beer.

[0081] Table 3 Effect of adding time of tricholoma grape juice on sensory scores

[0082]

[0083] By comparison, the effect of adding vinifera juice at 24h of the main fermentation in Example 1 is better. Under this condition, the finished beer has both vinifera and beer flavors, moderate acidity, a relatively clear body, and an alcohol content of 5.1%vol.

[0084] Test Result 2

[0085] The test results of Example 1 and Example 3 are listed below:

[0086] Determination of the alcohol content of the beer, the results Figure 4 are shown as follows. As the addition amount of the wild grape juice increases, the alcohol content of the beer shows a downward trend. The fermentable sugar content of the wild grape juice is 57.81 g / L, and the fermentable sugar content of the wort is 90.49 g / L. After adding the wild grape juice, the total fermentable sugar content of the wort decreases, resulting in a decrease in the alcohol content of the beer. However, the wort contains maltotriose that yeast cannot fully utilize, so the decrease in the alcohol content of the beer after adding the wild grape juice is relatively small.

[0087] Determination of the total acid content of the beer, the results Figure 5 are shown as follows. As the addition amount of the wild grape juice increases, the total acid content of the beer continuously increases. The wild grape variety is special. Compared with other varieties of wine grapes, it contains more organic acids and less sugar. Its total acid content is 18.0 mL / 100 mL, which is much higher than the total acid content of the wort (1.2 mL / 100 mL). The addition of the wild grape juice increases the total acid content of the wort, and yeast also produces some acidic substances during the fermentation process, increasing the total acid content of the wort.

[0088] Determination of the turbidity of the beer, the results Figure 6 are shown as follows. Adding a small amount of wild grape juice will cause an increase in the turbidity of the beer. When the addition amount of the wild grape juice accounts for 10% of the volume of the wort, the turbidity of the finished beer is the highest, reaching 28.79 EBC. After that, as the addition amount of the wild grape juice increases, the turbidity of the beer decreases, and the body of the beer becomes clear. This shows that when the addition amount of the wild grape juice is relatively large, the fine particles contained in the wild grape juice and the yeast have a certain flocculation effect, reducing the turbidity of the beer.

[0089] The sensory evaluation method was used to score the wild grape craft beer. The results are shown in Table 4. When the addition amount of the wild grape juice is relatively small, the score of the beer is relatively low. This is because when the addition amount is small, the fruity aroma of the wild grape in the beer is not obvious, and the relatively high turbidity also results in a lower score for the appearance. When the addition amount of the wild grape juice is 25% of the volume of the wort, the sensory score is the highest, reaching 84 points. The finished beer has a moderate acidity, a clear appearance, and a harmonious and mellow fruity and wine aroma. If the addition amount of the wild grape juice is further increased, the acidity of the beer is too high, and the drinking experience decreases. Finally, the optimal addition amount of the wild grape juice is selected as 25% of the volume of the wort. The alcohol content is moderate, being 4.96% vol, the turbidity is 13.42 EBC, the total acid is 5.6 mL / 100 mL, and the drinking experience is the best.

[0090] Table 4 Influence of the addition amount of wild grape juice on the sensory score

[0091]

[0092] In summary, the addition amount of Vitis heyneana Roem. juice in Example 1 is 25% of the volume of wort, and the effect is better. Under this condition, the sensory score of the Vitis heyneana Roem. craft beer is the highest, the alcohol content and total acid content are moderate, the turbidity of the wine body is the smallest, and the wine body is the most clarified.

[0093] Test result 3

[0094] The test results of Example 1 and Example 4 are listed as follows:

[0095] Measure the alcohol content of the beer, and the result Figure 7 shows that as the concentration of the final wort increases, the alcohol content of the beer also increases. The increase in the concentration of the final wort increases the content of fermentable sugars in the wort. After fermentation by yeast, more alcohol is produced. The increase in the concentration of the final wort will lead to an increase in osmotic pressure, reduce the water concentration in the cell's surrounding environment, and easily have a negative impact on yeast, such as a decrease in fermentation rate, an extension of the fermentation cycle, incomplete fermentation, etc. When the wort concentration reaches 18°P, it belongs to high-gravity brewing. The sugar reduction efficiency of yeast is lower than that in wort with a lower concentration. Excessive alcohol content will also have a certain toxic effect on yeast, causing changes in yeast cell morphology, a decrease in the number of generations used, a decrease in flocculability, autolysis, etc. Excessive alcohol content will also reduce the drinkability of the beer.

[0096] Measure the total acid content of the beer, and the result Figure 8 shows that yeast will produce organic acids during the fermentation process, resulting in an increase in the total acid content of the beer. The higher the concentration of the final wort, the higher the total acid content. As the concentration of the final wort increases, the total acid of the beer shows an increasing trend, which has a certain negative impact on improving the drinkability and re-drinkability of the Vitis heyneana Roem. craft beer. One of the characteristics of fruit craft beer is strong drinkability and re-drinkability. Therefore, choosing a lower concentration of the final wort has a certain promoting effect on the sensory experience of the beer.

[0097] Measure the turbidity of the beer, and the result Figure 9 shows that the turbidity of the beer increases with the increase in the concentration of the final wort. Especially when the concentration of the final wort is 18°P, the trend of turbidity increase is more obvious. Wort with a higher concentration has a negative impact on the flocculability of yeast, which is not conducive to the clarification of the beer.

[0098] The sensory evaluation method was used to score the fine-brewed beer made from Vitis heyneana Roem. et Schult. The results are shown in Table 5. When the final wort concentration was 12°P, the sensory score of the beer was the highest, reaching 84 points. Followed by the final wort concentration of 14°P, the sensory score of the beer was 82 points. The beer body was refreshing, with a prominent fruity aroma of Vitis heyneana Roem. et Schult., and the beer body was relatively clear. When the final wort concentration was lower than 12°P, the taste of Vitis heyneana Roem. et Schult. was relatively prominent, masking the taste of the beer. When the final wort concentration was greater than 14°P, the alcohol content was too high, and there was a hint of alcohol taste during tasting. The taste of the beer masked part of the taste of Vitis heyneana Roem. et Schult., and the higher turbidity of the beer body also led to a lower score for the appearance part.

[0099] Table 5 Influence of final wort concentration on sensory score

[0100]

[0101] In summary, in the single-factor experiment of the final wort concentration, 12°P was the optimal final wort concentration. Under this condition, the fine-brewed beer made from Vitis heyneana Roem. et Schult. had a moderate alcohol content, low total acid content and turbidity, and the highest sensory evaluation score.

[0102] Test result 4

[0103] The test results of Example 1 and Example 5 are listed as follows:

[0104] The alcohol content of the beer was measured, and the results Figure 10 showed that the addition amount of hops had little effect on the alcohol content of the beer. Alcohol was mainly produced by yeast through anaerobic fermentation to convert sugars into alcohol during the fermentation process. Hops contain about 2% of simple sugars, but the addition amount of hops was very small. Even for hazy IPA, where the addition amount of hops could reach dozens of grams, it could only bring a small amount of sugar to the beer, having little effect on the alcohol content of the beer.

[0105] The total acid content of the beer was measured, and the results Figure 11 showed that the addition amount of hops had little effect on the total acid of the beer. The main sources of the total acid in the beer were the acidic substances contained in the malt itself, the organic acids produced by yeast fermentation, the acids contained in the brewing water, and the acids used to adjust the pH of the mash. The main functions of hops were to provide bitterness, aroma, clarify the wort during boiling, maintain foam stability, etc.

[0106] The turbidity of the beer was measured, and the results Figure 12As shown, hops contain 4% - 10% polyphenolic substances. During the boiling process, polyphenols combine with proteins in the wort to form heat coagulants, which precipitate to the bottom of the boiling kettle or whirlpool, contributing to the clarification of the wort. When the addition amount of hops is small, the turbidity of the beer is high. As the addition amount of hops gradually increases, the clarifying effect of hops enhances and the turbidity of the beer decreases. However, when the addition amount of hops is too large, it leads to an excessive amount of polyphenols in the beer. The excessive polyphenols polymerize with the proteins in the beer, resulting in "cold haze" of the beer, an increase in the turbidity of the beer body. When the temperature rises, the "cold haze" phenomenon will disappear again.

[0107] The sensory evaluation method was used to score the Vitis heyneana Roem. et Schult. fine brewing beer. The results are shown in Table 6. When the addition amount of hops is 1.3 g / L, the sensory score of the beer is the highest, which is 84 points. At this time, the bitterness of the beer is moderate, and the beer body slightly has the aroma of hops, complementing the fruity aroma of Vitis heyneana Roem. et Schult. When the addition amount of hops is insufficient, the beer is relatively turbid, the appearance score is low, and the comprehensive score is also low. When the addition amount of hops is too large, it leads to an increase in the bitterness of the beer, the bitterness is rough, and the drinkability decreases.

[0108] Table 6 Influence of Hops Addition Amount on Sensory Score

[0109]

[0110] In summary, in the single-factor experiment of the addition amount of hops, 1.3 g / L is the optimal addition amount of hops. Under this condition, the Vitis heyneana Roem. et Schult. fine brewing beer has the highest sensory score, lower turbidity, and a relatively clear beer body.

[0111] Test Result 5

[0112] The test results of Example 1 and Example 6 are listed as follows:

[0113] According to the orthogonal experiment factor level table of the co-fermentation process of fruit juice wort in Table 1, nine groups of experimental schemes were combined. The experimental level combinations and analysis are shown in Table 7. k 1 , k 2 , k 3 are respectively the average values of the sensory scores corresponding to the three levels of each factor, and the R value is the range between the three k values, reflecting the influence degree of each factor on the sensory score.

[0114] The orthogonal experiment design and experimental result analysis of the co-fermentation of Vitis heyneana Roem. et Schult. fine brewing beer and fruit juice wort are shown in Table 7. The ranges of the addition amount of Vitis heyneana Roem. et Schult. juice, the final wort concentration, and the addition amount of hops are 3.0, 2.0, and 2.3 respectively. The influence degree of each factor on the fermentation degree is: addition amount of Vitis heyneana Roem. et Schult. juice > addition amount of hops > final wort concentration. The optimal factor level combination for the saccharification of Vitis heyneana Roem. et Schult. fine brewing beer is A 2 B 3 C 1, that is, when the addition amount of Vitis heyneana Roem. juice accounts for 25% of the volume of wort, the final wort concentration is 14°P, and the addition amount of hops is 1.0 g / L, which are the corresponding conditions of Example 1. Under this condition, a verification test is carried out. Under this formula condition, the sensory score of the Vitis heyneana Roem. craft beer is 86 points. The beer is brownish-yellow, clear and transparent, with white and delicate foam, full of Vitis heyneana Roem. flavor, coordinated fruit flavor and hop flavor, moderate acidity, and good drinkability and re-drinkability.

[0115] Table 7 Orthogonal experiment results and analysis of the co-fermentation process of Vitis heyneana Roem. craft beer juice and wort

[0116]

[0117] To sum up, the present invention provides a co-fermentation technology of juice and wort for a craft beer with Vitis heyneana Roem. flavor and strong nutritional and health care functions. By comparing the test results of Example 1 and Example 2, it is determined that it is better to add Vitis heyneana Roem. juice at 24 h of the main fermentation. By comparing the test results of Example 1 with those of Example 2, 3, and 4, that is, considering the influence of single factors such as the addition amount of Vitis heyneana Roem. juice, the final wort concentration, and the addition amount of hops on the beer flavor respectively, it is determined that the optimal addition amount of Vitis heyneana Roem. juice in the single-factor experiment is 25% of the wort volume, the optimal final wort concentration is 12°P, and the optimal addition amount of hops is 1.3 g / L. By comparing the test results of Example 1 and Example 5, that is, considering the influence of the three factors of the addition amount of Vitis heyneana Roem. juice, the final wort concentration, and the addition amount of hops on the beer flavor comprehensively, it is determined that the optimal process parameters of the orthogonal experiment for the co-fermentation of juice and wort are that the addition amount of Vitis heyneana Roem. juice is 25% of the wort volume, the final wort concentration is 14°P, and the addition amount of hops is 1.0 g / L. Since the single-factor experiment only considers a single factor, while the orthogonal experiment comprehensively considers multiple factors, the obtained optimal conditions are different. Finally, the co-fermentation conditions of adding Vitis heyneana Roem. juice at 24 h of the main fermentation, the addition amount of Vitis heyneana Roem. juice accounting for 25% of the wort volume, the final wort concentration of 14°P, and the addition amount of hops of 1.0 g / L are selected. At this time, the Vitis heyneana Roem. craft beer obtained has the best flavor. This provides a suitable solution for Vitis heyneana Roem. craft beer and is conducive to further exploring the market of fruit-flavored craft beer.

Claims

1. A juice-wort co-fermentation technology for brewing tricholoma craft beer, characterized in that: The following steps are involved: 1) Malt crushing: Weigh an appropriate amount of malt and crush it into pen-tip-sized particles, with the husk broken but not shattered; 2) Malt saccharification: Add appropriate amount of water and crushed malt into the saccharification tank, and use step-by-step temperature increase to saccharify to obtain a mixed liquid; 3) Filtration and washing of the spent grains: After saccharification, pump the wort to the boiling tank, then evenly sprinkle hot water on the spent grains layer to wash the spent grains, and pump the wort obtained from washing the spent grains to the boiling tank; 4) Wort boiling: Heat the wort to boiling and add hops twice during the boiling period; 5) Wort vortex sedimentation: The boiled wort is pumped to the vortex sedimentation tank, and the wort enters the vortex sedimentation tank from the side opening to settle. After vortex sedimentation, it is left to stand. The hot coagulants in the wort gather at the bottom of the vortex sedimentation tank under the action of centrifugal force, and the clarified wort is introduced into the fermentation bottle through the outlet at the bottom. 6) Cooling and tanking wort: pump the clarified wort into the fermentation bottle and quickly cool the wort; 7) Fermentation: Inoculate the activated yeast into the wort for fermentation. The fermentation is divided into five stages, namely, primary fermentation, reduction of diacetyl, cooling and precipitation, secondary fermentation, cold storage and ripening. In the primary fermentation stage, pubescent grape juice is added.

2. The juice-wort co-fermentation technology for brewing vinifera craft beer according to claim 1, characterized in that: In step 1) malt crushing, the malt is Pilsner malt and Munich malt in a mass ratio of 9 to 10:

1.

3. The juice-wort co-fermentation technology for brewing vinifera craft beer according to claim 1, characterized in that: Step 2) During malt saccharification, the water-to-malt ratio of water volume to malt mass is 3.0~5.0 L / kg.

4. The juice-wort co-fermentation technology for brewing vinifera craft beer according to claim 1, characterized in that: Step 2) In the malt saccharification, the step-by-step temperature increase saccharification includes: the first step, adding water and heating to 68-70°C, adding crushed malt and stirring evenly; the second step, keeping warm at 68-70°C for 58-62 min; the third step, heating to 70-74°C and keeping warm until the iodine test does not turn blue; the fourth step, raising the temperature to 76-80°C, keeping warm for 8-12 min, and stopping the enzyme.

5. The juice-wort co-fermentation technology for brewing vinifera craft beer according to claim 1, characterized in that: In step 4), during the wort boiling, the boiling time is 58-62 min in total, and the amount of hops added is 0.9-1.5 g / L wort; the first hops are added at the beginning of boiling, and the added hops are Chinook hops, and the weight of the added hops accounts for 42%-44% of the total hops added; Chinook and Fager mixed hops are added 4-5 min before the end of boiling, and are added according to 28%-29% of the total hops added.

6. The juice-wort co-fermentation technology for brewing vinifera craft beer according to claim 1, characterized in that: Step 6) The wort is cooled and put into tanks, and the wort concentration is set at 10~14 °P.

7. The juice-wort co-fermentation technology for brewing vinifera craft beer according to claim 1, characterized in that: Step 7) Fermentation: Yeast inoculation temperature is 18~20 ℃.

8. The juice-wort co-fermentation technology for brewing vinifera craft beer according to claim 1, characterized in that: Step 7) The fermentation is divided into five stages: the first stage is the main fermentation, the time is 5-7 days, and the fermentation temperature is 19-20°C; the tricholoma juice is added when the main fermentation reaches 24 hours, and the amount of tricholoma juice added is 23%-25% of the volume of the wort, and then the juice and the wort are co-fermented; the second stage is the post-ripening stage, diacetyl reduction is carried out, the fermentation temperature in this stage is 21-22°C, and the fermentation is 3-4 days; the third stage is the cooling and precipitation stage, the fermentation temperature in this stage is 3-4°C, and the time is 36-60 hours; the fourth stage is the secondary fermentation stage, the upper layer of sake after cold precipitation is transferred to a brown glass bottle, white sugar is added, and it is placed in a constant temperature incubator at 24-26°C for a second fermentation, and the time is 4-6 days; the fifth stage is the cold storage and ripening stage, the beer after the second fermentation is placed in a 4°C refrigerator for after-ripening for 12-14 days.

9. A vinifera craft beer, characterized in that: Brewed by the juice-wort co-fermentation technology described in any one of claims 1 to 8.

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