A grape cold maceration whole berry fermentation method

Abstract

The application provides a grape cold immersion whole-grain fermentation method, which comprises the following steps: putting whole grapes into a fruit skin protection solution and soaking for 10-30 min; the fruit skin protection solution is prepared by dissolving a fruit skin protection agent in a solvent and controlling the solid content to be less than 8%, and the fruit skin protection agent comprises cellulose and pectin in a mass ratio of 3-5:1; drying the whole grapes, removing the stems and cores of the dried whole grapes, and obtaining whole-grain grapes; adding the whole-grain grapes into a fermentation vat, and sequentially performing low-temperature immersion treatment, alcohol fermentation treatment and malic-lactic fermentation treatment in the fermentation vat; performing pressing and skin residue separation operations on the whole-grain grapes after fermentation is completed, and terminating the malic-lactic fermentation. The method can effectively solve the problem that, in the existing grape fermentation method, grape skin is broken during the fermentation process, which leads to poor tannin entering the wine, and adversely affects the flavor of the grape wine.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of grape wine brewing, and particularly relates to a grape cold immersion whole-grain fermentation method. BACKGROUND

[0002] Grape wine brewing is a time-honored art, and its flavor and quality are influenced by various factors, including grape varieties, growing environments, and brewing processes. Grape fermentation is a key process in brewing grape wine. Traditional grape wine brewing methods usually involve removing stems and crushing grapes before fermentation, thereby converting sugar in the grapes into alcohol and carbon dioxide.

[0003] Although the traditional fermentation method is simple to operate, it has some shortcomings. The crushing process causes grape skin cells and seeds to rupture, releasing a large amount of tannins, especially poor-quality tannins. These tannins can give grape wine a bitter, harsh taste, affecting the overall flavor and quality of grape wine. In addition, crushing increases the contact area between juice and skin, accelerating oxidation and adversely affecting the retention of flavor substances.

[0004] In recent years, whole-grain fermentation technology has gradually gained attention. Whole-grain fermentation refers to preserving the integrity of grape berries during fermentation without crushing. This method can reduce the release of poor-quality tannins, thereby improving the taste of grape wine. At the same time, whole-grain fermentation can increase the complexity and layering of grape wine, enhancing the overall quality of grape wine. However, due to the fact that grape skins are easily broken during the process of removing stems, poor-quality tannins enter the wine, adversely affecting the flavor of grape wine. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a grape cold immersion whole-grain fermentation method to solve the problem that, in the existing grape fermentation method, grape skins are inevitably broken during the fermentation process, causing poor-quality tannins to enter the wine and adversely affecting the flavor of grape wine.

[0006] To solve the above problems of the present application, the present application provides a grape cold immersion whole-grain fermentation method, comprising: placing whole bunches of grapes into a skin protection solution for 10-30 min and then taking them out; the skin protection solution is prepared by dissolving a skin protection agent in a solvent and controlling the solid content to be no more than 8%, the skin protection agent comprising cellulose and pectin in a mass ratio of 3-5:1; drying the whole bunches of grapes, removing the stems and grape cores of the whole bunches of grapes after drying, and obtaining whole-grain grapes; adding the whole-grain grapes to a fermentation tank, and sequentially performing low-temperature immersion treatment, alcoholic fermentation treatment, and malolactic fermentation treatment in the fermentation tank; and performing pressing and skin residue separation operations on the whole-grain grapes that have completed fermentation to terminate malolactic fermentation.

[0007] The grape cold immersion whole particle fermentation method provided in the scheme includes the following steps: a whole grape is immersed in a fruit peel protection solution for 10-30 minutes, and then taken out; and the whole particle grape is added into a fermentation barrel.

[0008] In order to avoid unstable grape quality caused by premature or late soaking, as a preferred option, the step of immersing the whole grape in the fruit peel protection solution for 10-30 minutes includes the following steps:

[0009] The step of immersing the whole grape in the fruit peel protection solution for 10-30 minutes includes the following steps: the whole grape is immersed in the fruit peel protection solution for 10-30 minutes, and then taken out within 3 days before fermentation.

[0010] Further, the cellulose includes at least one of sodium carboxymethyl cellulose, microcrystalline cellulose and hydroxypropyl cellulose.

[0011] Further, the solvent includes water.

[0012] In order to further improve the stability of the fruit peel, as a preferred option, the fruit peel protection agent includes cellulose, pectin and calcium agent with a mass ratio of 3-5:1:1-3.

[0013] In order to further optimize the brewing process of the grape wine, as a preferred option, the broken part of the whole particle grape does not exceed 15%.

[0014] Further, the step of adding the whole particle grape into the fermentation barrel includes the following steps: the whole particle grape is layered into the fermentation barrel according to the intact part and the broken part.

[0015] The scheme ensures that the broken part does not exceed 15% by layering the intact part and the broken part of the whole particle grape, and the broken part releases tannin faster due to cell rupture. The intact part can slowly release sugar to maintain stable fermentation. Layering can control the release speed of tannin, avoid the large release of tannin in the early stage of fermentation, and help to balance the flavor of the final wine body.

[0016] Further, the step of immersing the whole grape in the fruit peel protection solution for 10-30 minutes includes the following steps: the whole grape is immersed in the fruit peel protection solution for 10-30 minutes, and then taken out within 3 days before fermentation.

[0017] Further, the low-temperature immersion treatment includes the following steps: part of carbon dioxide gas is filled into the fermentation barrel, the whole particle grape is added into the fermentation barrel, the filling of carbon dioxide gas is continued until the fermentation barrel is filled, the fermentation barrel is closed, and the low-temperature immersion is continued for 10-15 days.

[0018] Further, the alcoholic fermentation process comprises: inoculating the activated yeast into the fermentation tank, and fermenting for 7-10 days.

[0019] In order to more accurately control the end point of the whole grape fermentation process, before the pressing and pomace separation operation of the whole grape fermentation, further comprising:

[0020] Sampling and detecting the liquid in the fermentation tank, and determining that the whole grape fermentation is completed when the specific gravity of the liquid in the fermentation tank is detected to be between 0.990 and 1.000.

[0021] The technical effect of the present application is that:

[0022] 1. In the grape cold immersion whole grain fermentation method provided by the present application, the whole grape is pretreated by the fruit skin protection liquid before fermentation, a protection layer is formed on the surface of the grape skin, and the rupture of the skin in the subsequent process is reduced. At the same time, the whole grain fermentation retains the integrity of the grape berries, avoids the crushing process, further reduces the release of inferior tannins, and improves the flavor and taste of the grape wine, so that the grape wine has richer fruit aroma and softer taste.

[0023] 2. The present application adds the whole part and the broken part of the whole grain grape by layering, ensures that the broken part is not more than 15%, and the broken part releases tannins faster due to cell rupture. The whole part can slowly release sugar to maintain the stable progress of fermentation. Controlling the broken part within 15% and combining the layering adding method can control the release speed of tannins, avoid the large release of inferior tannins in the early stage of fermentation, affect the taste of grape wine, and improve the production efficiency of grape wine. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application will be further described in detail below in combination with embodiments. It should be understood that the following embodiments are only used to more clearly illustrate the technical scheme of the present application, and therefore only serve as examples, but cannot limit the protection scope of the present application.

[0025] The bacterial agent used in the alcoholic fermentation process in the present application is ZYMAFLORE XPURE, which is purchased from Tianjin Shengfeng Tiancheng Business and Trade Co., Ltd. The bacterial agent used in the malic acid-lactic acid fermentation process is Lactobacillus acidophilus, and OENO 1 is selected, which is purchased from Ningxia Nuomeng Biological Technology Co., Ltd. The specific implementation of the present application will be described in detail below in combination with specific embodiments.

[0026] The present application provides a grape cold immersion whole grain fermentation method, comprising the following steps:

[0027] S11: soaking the whole cluster of grapes in the peel protection liquid for 10-30 min and then taking out; the peel protection liquid is prepared by dissolving a peel protection agent in a solvent and controlling the solid content to be no more than 8%, and the peel protection agent comprises cellulose and pectin in a mass ratio of 3-5:1;

[0028] Specifically, the whole cluster of grapes is selected to be of moderate maturity and free of pests and diseases. Cellulose, as a high molecular polymer, can form a thin film on the surface of the peel and play a physical protection role. Pectin has good adhesion and film forming property, and can cooperate with cellulose to fix the protective layer on the surface of the peel. The solvent serves as a carrier to uniformly disperse cellulose and pectin and facilitate the soaking of the grapes. The pretreatment of the whole cluster of grapes by the peel protection liquid before fermentation, in the soaking process, the peel protection liquid will be attached and coated on the surface of the grape peel to form a protective film, which can effectively reduce the rupture of the peel in the subsequent processing and thus reduce the release of tannin, especially the release of inferior tannin.

[0029] In an implementation manner, the cellulose comprises at least one of sodium carboxymethyl cellulose, microcrystalline cellulose and hydroxypropyl cellulose.

[0030] In an implementation manner, the solvent comprises water.

[0031] In an implementation manner, the peel protection agent comprises 6-15 parts of cellulose, pectin and calcium agent in a mass ratio of 3-5:1:1-3.

[0032] Specifically, calcium ions are an important component of plant cell walls and can combine with pectic acid to form calcium bridges, thereby enhancing the strength and stability of the peel cell wall. Preferably, the calcium agent comprises amino acid chelated calcium.

[0033] It should be understood that the timing of grape soaking will have a certain impact on grape fermentation. If the protective layer is formed too early, the protective layer may fail during fermentation, which cannot protect the peel, and thus the release of inferior tannin is too fast. Therefore, in an implementation manner, the soaking timing is controlled within 3 days before fermentation, specifically including:

[0034] In an implementation manner, the whole cluster of grapes is soaked in the peel protection liquid for 10-30 min and then taken out within 3 days before fermentation.

[0035] S12: drying the whole cluster of grapes, removing the peduncle and grape core of the whole cluster of grapes after drying, and obtaining whole-grain grapes;

[0036] Specifically, the stem contains more tannin and bitter substances, and removing the stem can avoid the wine from appearing green taste, affecting the taste of the wine. Because the whole particle fermentation process is relatively slow, especially after removing the stem, the small hole at the top of the grape can only allow a small amount of yeast to enter, so removing the core of the grape can expand the channel for yeast to enter, promote juice exudation and gas exchange. It should be noted that the core of the grape here refers to the part connecting the top of the grape and the stem, not the grape seed itself.

[0037] S13: adding the whole particle grape into a fermentation vat, and sequentially performing low-temperature soaking treatment, alcohol fermentation treatment and malic-lactic fermentation treatment in the fermentation vat;

[0038] It should be understood that grape skin damage is inevitable during the process of removing the stem. In order to control the quality, the grape after removing the stem needs to be screened again, and the broken part in the whole particle grape is controlled to be not more than 15%.

[0039] In an implementation manner, adding the whole particle grape into the fermentation vat comprises:

[0040] The whole particle grape is added into the fermentation vat in layers.

[0041] Specifically, by adding the whole particle grape in layers, the broken part is ensured to be not more than 15%, and the broken part releases tannin quickly due to cell rupture. The whole particle grape can slowly release sugar to maintain stable fermentation. Controlling the broken part to be not more than 15% and adding in layers can control the release speed of tannin, avoid a large amount of poor tannin from being released in the early stage of fermentation, affect the taste of the wine, and improve the production efficiency of the wine.

[0042] In an implementation manner, the low-temperature soaking treatment comprises:

[0043] Carbon dioxide gas is filled into the fermentation vat, the whole particle grape is added into the fermentation vat, the filling of the carbon dioxide gas is continued until the fermentation vat is filled, the fermentation vat is closed, and the low-temperature soaking is continued for 10-15 days at 8-12°C.

[0044] Preferably, the carbon dioxide gas needs to be supplemented in time during the fermentation process of the whole particle grape.

[0045] In an implementation manner, the alcohol fermentation treatment comprises:

[0046] The temperature of the fermentation vat is controlled to be 18-20°C, activated yeast is inoculated into the fermentation vat, and the fermentation is continued for 7-10 days.

[0047] S14: performing pressing and skin residue separation operation on the whole particle grape after fermentation is completed, and terminating the malic-lactic fermentation.

[0048] In order to accurately determine the completion of fermentation, in an implementation mode, before the pressing and pomace separation operation of the whole grape fermented to completion, further comprising:

[0049] Sampling and detecting the liquid in the fermentation vat, when the specific gravity of the liquid in the fermentation vat is detected to be between 0.990 and 1.000, it is determined that the whole grape fermentation is completed.

[0050] According to the embodiments provided by the present application, some specific experiments have been carried out on the present application. From these examples and comparative examples, it can be seen that the scheme provided by the present application has obtained good effects. It needs to be explained that the following examples are only used to illustrate the present application in detail, and do not limit the protection scope of the application in any way.

[0051] Example 1

[0052] S21: Within 3 days before fermentation, 100 parts of whole grape are soaked in 100 parts of fruit skin protection solution for 20 minutes and then taken out; the fruit skin protection solution is prepared by dissolving a fruit skin protection agent in a solvent and controlling the solid content to be not more than 8%, and the fruit skin protection agent includes cellulose and pectin with a mass ratio of 3-5:1;

[0053] S22: The whole grape is dried, and the peduncle and grape core of the whole grape after drying are removed to obtain whole grape;

[0054] S23: The whole grape is added to the fermentation vat, and low-temperature immersion treatment, alcohol fermentation treatment and malic acid-lactic acid fermentation treatment are sequentially performed in the fermentation vat;

[0055] S231: One-third of carbon dioxide gas is filled into the fermentation vat, the whole grape is added to the fermentation vat, the filling of carbon dioxide gas is continued until it is filled, the fermentation vat is closed, and the low-temperature immersion is continued at a reaction temperature of 10℃ for 12 days;

[0056] S232: The temperature of the fermentation vat is controlled at 19±1℃, and activated yeast bacteria are inoculated into the fermentation vat, and fermentation is carried out for 9 days;

[0057] S233: The temperature of the fermentation vat is controlled at 25±1℃, and lactic acid bacteria are added to the fermentation vat for malic acid-lactic acid fermentation;

[0058] S24: Sampling and detecting the liquid in the fermentation vat, when the specific gravity of the liquid in the fermentation vat is detected to be less than 1.010, it is determined that the whole grape fermentation is completed;

[0059] S25: The whole grape fermented to completion is subjected to pressing and pomace separation operation, and the malic acid-lactic acid fermentation is terminated.

[0060] Examples 2~7

[0061] Examples 2~6 are different from Example 1 in the amount of substances added in each step and process control. The difference is that the ratio of each substance added in the skin protection solution of Examples 2 and 3 is different from Example 1, and Example 4 further adds amino acid chelated calcium as calcium agent in the skin protection solution in step S1, and the soaking time in the skin protection solution of Examples 5 and 6 is different from Example 1. Further, Example 7 further performs secondary screening on the de-stemmed grapes in step S23, controls the broken part of the whole grape to be not more than 15%, and layers the whole part and the complete part into the fermentation vat.

[0062] Comparative Example 1

[0063] Comparative Example 1 is different from Example 1 in that Comparative Example 1 does not perform step S21, that is, does not perform skin protection treatment, but only performs cleaning treatment of grapes. The other steps are the same as Example 1.

[0064] Comparative Example 2

[0065] Comparative Example 2 is different from Example 1 in that Comparative Example 2 only soaks for 5 min in the process of performing step S21. The other steps are the same as Example 1.

[0066] Comparative Example 3

[0067] Comparative Example 3 is different from Example 1 in that Comparative Example 3 soaks for 40 min in the process of performing step S21. The other steps are the same as Example 1.

[0068] Comparative Example 4

[0069] Comparative Example 4 is different from Example 1 in that Comparative Example 4 further performs secondary screening on the de-stemmed grapes in step S23, controls the broken part of the whole grape to be 25% of the total grape amount.

[0070] The control parameters of each step of Examples 2~7 and Comparative Examples 1~4 are shown in Table 1 and Table 2.

[0071] Table 1 Parameter configuration of each step of Examples 1~7

[0072]

[0073] Table 2 Parameter configuration of each step of Comparative Examples 1~4

[0074]

[0075] The total content of phenolic substances and the content of tannins of the grape wine obtained after the termination of fermentation in step S23 of each of the above examples and comparative examples are determined by spectrophotometry. The determination results are shown in Table 3.

[0076] Table 3 Determination results of each example and comparative example

[0077]

[0078] It can be seen from the above Example 1 and Comparative Example 1 that the use of the whole peel protection and the whole grain fermentation process can significantly reduce the tannin content in the wine during fermentation.

[0079] It can be seen from the above Examples 1 and 4 that the addition of calcium agent in the peel protection solution can further enhance the peel strength and reduce the increase of tannin content caused by peel rupture during fermentation.

[0080] It can be seen from the above Examples 1, 5-6 and Comparative Examples 2-3 that the soaking time of the peel protection solution has a certain influence on grape fermentation. It is speculated that the reason is that the soaking time is too short, which fails to effectively form a protective layer, resulting in the rupture of the peel during subsequent processing and the release of more inferior tannins. The soaking time is too long, which cannot significantly reduce the release of tannins, so the soaking time is controlled at 10-30 min in consideration of production efficiency.

[0081] It can be seen from the above Examples 1, 5, 7 and Comparative Example 4 that the addition of excessive broken parts during the whole grain fermentation without layering will cause the increase of tannin content, while the addition of appropriate broken parts will not have excessive influence on the increase of tannin content.

[0082] It can be seen from the above examples, comparative examples and experimental conclusions that the grape cold soaking whole grain fermentation method provided by the present application can effectively solve the problem that the grape skin is inevitably ruptured during the fermentation process of the existing grape fermentation method, which causes inferior tannins to enter the wine and adversely affects the flavor of the wine, which is easy to popularize and apply in actual production. It can be further seen that the beneficial effects of the present application are remarkable.

[0083] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or make equivalent substitutions for part or all of the technical features; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A grape cold soak whole berry fermentation method, characterized by, The method comprises the following steps: immersing the whole cluster of grapes in a skin protection solution for 10-30 minutes, and then taking out the whole cluster of grapes; the skin protection solution is prepared by dissolving a skin protection agent in a solvent and controlling the solid content to be less than 8%, wherein the skin protection agent comprises cellulose, pectin and calcium agent in a mass ratio of 3-5:1:1-3; the cellulose is at least one of sodium carboxymethyl cellulose, microcrystalline cellulose and hydroxypropyl cellulose; drying the whole cluster of grapes, and removing the stems and grape cores of the whole cluster of grapes after drying to obtain whole-grain grapes; the grape core refers to the part where the top of the grape is connected with the stem; the broken part in the whole-grain grapes is less than 15%; adding the whole-grain grapes and the broken part into a fermentation vat in layers, and sequentially performing low-temperature immersion treatment, alcohol fermentation treatment and malolactic fermentation treatment in the fermentation vat; the low-temperature immersion treatment comprises the following steps: filling part of carbon dioxide gas into the fermentation vat, adding the whole-grain grapes into the fermentation vat, continuously filling carbon dioxide gas until the fermentation vat is filled, closing the fermentation vat, and continuously performing low-temperature immersion for 10-15 days. performing pressing and skin residue separation on the whole-grain grapes after fermentation to terminate the malolactic fermentation.

2. The grape cold soak whole cluster fermentation method of claim 1, wherein, The solvent is water.

3. The whole grape cold soak whole cluster fermentation method of claim 1, wherein, The step of immersing the whole cluster of grapes in the skin protection solution for 10-30 minutes before taking out the whole cluster of grapes comprises the following steps: immersing the whole cluster of grapes in the skin protection solution for 10-30 minutes before taking out the whole cluster of grapes within 3 days before fermentation.

4. The whole grape cold soak whole cluster fermentation method of claim 1, wherein, The alcohol fermentation treatment comprises the following steps: inoculating activated yeast into the fermentation vat, and fermenting for 7-10 days.

5. The whole grape cold soak whole cluster fermentation method of claim 1, wherein, Before the step of performing pressing and skin residue separation on the whole-grain grapes after fermentation, the method further comprises the following steps: sampling and detecting the liquid in the fermentation vat, and determining that the fermentation of the whole-grain grapes is completed when the specific gravity of the liquid in the fermentation vat is detected to be between 0.990 and 1.000.

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