Whole-particle fermentation method for cold impregnation of grapes

Abstract

The invention provides a grape cold dipping whole particle fermentation method. The grape cold dipping whole particle fermentation method comprises the following steps: putting a whole string of grapes into a peel protection solution, soaking for 10-30 minutes, and then taking out; the pericarp protection liquid is prepared by dissolving a pericarp protection agent in a solvent and controlling the solid content not to exceed 8%, and the pericarp protection agent comprises cellulose and pectin in a mass ratio of (3-5): 1; drying the whole string of grapes, and removing stems and grape cores of the dried whole string of grapes to obtain whole granular grapes; adding the whole-particle grapes into a fermentation barrel, and sequentially carrying out low-temperature dipping treatment, alcoholic fermentation treatment and malic acid-lactic acid fermentation treatment in the fermentation barrel; performing squeezing and peel-residue separation operation on the fermented whole-particle grapes, and terminating malic acid-lactic acid fermentation. According to the method disclosed by the invention, the peel is protected before fermentation, so that the problem that the inferior tannin enters the wine liquid to generate an adverse effect on the flavor of the wine due to the fact that the grape peel is broken in the fermentation process in the existing grape fermentation method can be effectively solved.

Description

Technical Field

[0001] The present application relates to the technical field of wine brewing, and in particular to a method for cold-soaking whole grape grapes for fermentation. Background Art

[0002] Winemaking is a skill with a long history. Its flavor and quality are affected by many factors, including grape varieties, growing environment and brewing process. Grape fermentation is the key process in making wine. The traditional winemaking method usually involves removing the stems and crushing the grapes before fermenting them, thereby converting the 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 will cause the grape skin cells and pits to rupture, releasing a large amount of tannins, especially low-quality tannins. These tannins will give the wine a bitter and rough taste, affecting the overall flavor and quality of the wine. In addition, crushing will increase the contact area between the juice and the skin, accelerate oxidation, and is not conducive to the retention of flavor substances.

[0004] In recent years, whole-grain fermentation technology has gradually attracted attention. Whole-grain fermentation refers to retaining the integrity of grape berries during the fermentation process without crushing them. This method can reduce the release of inferior tannins, thereby improving the taste of wine. At the same time, whole-grain fermentation can also increase the complexity and layering of wine, and improve the overall quality of wine. However, since the grape skin is easily broken during the process of destemming, inferior tannins enter the wine, which has an adverse effect on the flavor of the wine. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a whole grape cold soaking fermentation method to solve the problem that the grape skin will inevitably rupture during the fermentation process of the existing grape fermentation method, resulting in inferior tannins entering the wine and having an adverse effect on the flavor of the wine.

[0006] In order to solve the above-mentioned problem of the present application, the present application provides a whole grape cold soaking fermentation method, comprising: placing a whole bunch of grapes into a peel protection liquid and soaking for 10 to 30 minutes and then taking it 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 to 5:1; drying the whole bunch of grapes, removing the stalks and grape cores of the whole bunch of grapes after drying, and obtaining whole grapes; adding the whole grapes into a fermentation barrel, and sequentially performing low-temperature soaking treatment, alcohol fermentation treatment and malic acid-lactic acid fermentation treatment in the fermentation barrel; pressing and skin-dregs separation operations on the whole grapes that have completed fermentation, and terminating malic acid-lactic acid fermentation.

[0007] In the grape cold soaking whole grape fermentation method provided by the present application, the whole bunch of grapes is pre-treated with a skin protection liquid before fermentation to form a protective layer on the surface of the grape skin, thereby reducing the cracking of the skin during subsequent processing. At the same time, the use of whole grape fermentation retains the integrity of the grape berries, further reducing the release of inferior tannins, thereby improving the flavor and taste of the wine, making the wine have a richer fruity aroma and a softer taste.

[0008] In order to avoid unstable grape quality caused by soaking too early or too late, as a better option, the whole bunch of grapes is soaked in the peel protection liquid for 10 to 30 minutes and then taken out, which includes:

[0009] Within 3 days before fermentation, soak the whole bunch of grapes in the skin protection solution for 10 to 30 minutes and then take them out.

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

[0011] Further, the solvent includes water.

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

[0013] In order to further optimize the winemaking process, as a better choice, the broken part of the whole grapes does not exceed 15%.

[0014] Furthermore, adding the whole grapes into the fermentation barrel comprises: adding the intact part and the broken part of the whole grapes into the fermentation barrel in layers.

[0015] This solution adds the intact and broken parts of whole grapes in layers, ensuring that the broken part does not exceed 15%. The broken part releases tannins faster due to cell rupture. The intact part can slowly release sugar to maintain the stable fermentation. Layered addition can control the release rate of tannins, avoid a large amount of tannins released in the early stage of fermentation, which affects the taste of the wine, and help balance the flavor of the final wine.

[0016] Furthermore, soaking the whole bunch of grapes in the fruit skin protection liquid for 10 to 30 minutes and then taking them out includes: within 3 days before fermentation, soaking the whole bunch of grapes in the fruit skin protection liquid for 10 to 30 minutes and then taking them out.

[0017] Furthermore, the low-temperature immersion treatment includes: filling a portion of carbon dioxide gas into the fermentation barrel, adding whole grapes into the fermentation barrel, continuously filling the carbon dioxide gas until the barrel is full, sealing the fermentation barrel, and continuously immersing at low temperature for 10 to 15 days.

[0018] Furthermore, the alcohol fermentation process includes: inoculating activated yeast into a fermentation barrel and fermenting for 7 to 10 days.

[0019] In order to more accurately control the end point of the whole grape fermentation process, before the whole grapes that have completed fermentation are pressed and the skin and pulp are separated, the following steps are also included:

[0020] The liquid in the fermentation barrel is sampled and tested, and when it is detected that the specific gravity of the liquid in the fermentation barrel is between 0.990 and 1.000, it is determined that the fermentation of the whole grapes is completed.

[0021] The technical effects of this application are:

[0022] 1. In the grape cold soaking whole grape fermentation method provided by the present application, the whole bunch of grapes is pretreated with a skin protection liquid before fermentation to form a protective layer on the surface of the grape skin, thereby reducing the breakage of the skin during subsequent processing. At the same time, the use of whole grape fermentation retains the integrity of the grape berries, avoids the crushing process, and further reduces the release of inferior tannins, thereby improving the flavor and taste of the wine, making the wine have a richer fruity aroma and a softer taste.

[0023] 2. The present application scheme ensures that the broken part does not exceed 15% by adding the intact part and the broken part of the whole grape in layers. The broken part releases tannins faster due to cell rupture. The intact part can slowly release sugar to maintain the stable fermentation. Controlling the broken part within 15% and combining it with the layered addition can control the release rate of tannins, avoid the release of a large amount of inferior tannins in the early stage of fermentation, affect the taste of the wine, and improve the production efficiency of the wine. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the present invention more clear, the present invention is further described in detail below in conjunction 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 are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0025] The bacterial agent used in the alcohol fermentation treatment in the embodiment of the present application is ZYMAFLORE XPURE, which is purchased from Tianjin Shengfeng Tiancheng Trading Co., Ltd. The bacterial agent used in the malic acid-lactic acid fermentation treatment is Lactobacillus acidophilus, OENO 1 is selected, and is purchased from Ningxia Nomen Biotechnology Co., Ltd. The specific implementation of the present invention is described in detail below in conjunction with specific embodiments.

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

[0027] S11: soaking the whole bunch of grapes in a peel protection liquid for 10 to 30 minutes and then taking them 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 includes cellulose and pectin in a mass ratio of 3 to 5:1;

[0028] Specifically, the whole bunch of grapes selected are those with 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 to play a physical protective role. Pectin has good viscosity and film-forming properties, and can work synergistically with cellulose to fix the protective layer on the surface of the peel. The solvent is used as a carrier to evenly disperse cellulose and pectin, and facilitate the soaking of grapes. Before fermentation, the whole bunch of grapes is pretreated with peel protection liquid. During the soaking process, the peel protection liquid will adhere to and coat the surface of the grape peel to form a protective film, which effectively reduces the rupture of the peel during subsequent processing and thereby reduces the release of tannins, especially the release of inferior tannins.

[0029] In one implementation, the cellulose includes at least one of sodium carboxymethylcellulose, microcrystalline cellulose, and hydroxypropyl cellulose.

[0030] In one implementation, the solvent includes water.

[0031] In one implementation, the peel protective agent includes 6 to 15 parts of cellulose, pectin and calcium agent in a mass ratio of 3 to 5:1:1 to 3.

[0032] Specifically, calcium ions are an important component of plant cell walls and can combine with pectin acid to form calcium bridges, thereby enhancing the strength and stability of the fruit peel cell walls. 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 and fail to protect the skin, which will lead to the release of inferior tannins too quickly. Therefore, in one implementation, the soaking time is controlled within 3 days before fermentation, specifically including:

[0034] Within 3 days before fermentation, soak the whole bunch of grapes in the skin protection solution for 10 to 30 minutes and then take them out.

[0035] S12: drying the whole bunch of grapes, removing the stalks and grape cores of the whole bunch of grapes after drying, to obtain whole grapes;

[0036] Specifically, the stems contain more tannins and bitter substances. Removing the stems can avoid the green taste of the wine, which affects the taste of the wine. Since the whole grain fermentation process is relatively slow, especially after the stems are removed, the small holes on the top of the grapes can only allow a small amount of yeast to enter. Therefore, removing the grape core can expand the channel for yeast to enter, promote juice exudation and gas exchange. It should be noted that the grape core here refers to the part where the top of the grape connects to the stem, not the grape seed itself.

[0037] S13: adding the whole grapes into a fermentation barrel, and sequentially performing low-temperature immersion treatment, alcohol fermentation treatment and malic acid-lactic acid fermentation treatment in the fermentation barrel;

[0038] It should be understood that grape skins are inevitably damaged during the process of destemming. In order to control the quality, the destemmed grapes need to be screened a second time to control the broken parts in the whole grapes to not exceed 15%.

[0039] In one implementation, adding whole grapes to a fermentation tank comprises:

[0040] The intact part and the crushed part of the whole grapes are added to the fermentation tank in layers.

[0041] Specifically, the intact part and the broken part of the whole grape are added in layers to ensure that the broken part does not exceed 15%. The broken part releases tannins faster due to cell rupture. The intact part can slowly release sugar to maintain the stable fermentation. Controlling the broken part within 15% and adding it in layers can control the release rate of tannins, avoid the release of a large amount of inferior tannins in the early stage of fermentation, affect the taste of the wine, and improve the production efficiency of the wine.

[0042] In one implementation, the low temperature impregnation treatment includes:

[0043] Fill the fermentation barrel with part of carbon dioxide gas, add whole grapes into the fermentation barrel, continue to fill with carbon dioxide gas until it is full, seal the fermentation barrel, and continue low-temperature immersion at 8-12° C. for 10-15 days.

[0044] Preferably, carbon dioxide gas is regularly added during the fermentation of whole grapes.

[0045] In one implementation, the alcohol fermentation process includes:

[0046] The temperature of the fermentation barrel is controlled between 18 and 20°C, activated yeast is inoculated into the fermentation barrel, and fermentation is carried out for 7 to 10 days.

[0047] S14: The fermented whole grapes are squeezed and the skins and residues are separated to terminate the malic acid-lactic acid fermentation.

[0048] In order to accurately determine whether the fermentation is complete, in one implementation, before the whole grapes that have completed the fermentation are squeezed and the skin and residue are separated, the method further includes:

[0049] The liquid in the fermentation barrel is sampled and tested, and when it is detected that the specific gravity of the liquid in the fermentation barrel is between 0.990 and 1.000, it is determined that the fermentation of the whole grapes is completed.

[0050] According to the implementation mode provided in the present application, some specific experiments have been conducted on the present application. From these embodiments and comparative examples, it can be seen that the scheme provided in the present application has achieved better results. It should be noted that the following embodiments are only used to illustrate the present invention in detail and do not limit the scope of protection of the invention in any way.

[0051] Example 1

[0052] S21: within 3 days before fermentation, 100 parts of whole bunches of grapes are placed in 100 parts of peel protection liquid by mass and soaked for 20 minutes before being taken 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 includes cellulose and pectin in a mass ratio of 3 to 5:1;

[0053] S22: drying the whole bunch of grapes, and removing the stems and grape cores of the whole bunch of grapes after drying to obtain whole grapes;

[0054] S23: adding whole grapes into a fermentation barrel, and sequentially performing low-temperature immersion treatment, alcohol fermentation treatment and malic acid-lactic acid fermentation treatment in the fermentation barrel;

[0055] S231: Fill the fermentation barrel with one third of carbon dioxide gas, add whole grapes into the fermentation barrel, continue to fill with carbon dioxide gas until it is full, seal the fermentation barrel, and continue low-temperature maceration at a reaction temperature of 10° C. for 12 days;

[0056] S232: controlling the temperature of the fermentation barrel at 19±1° C., inoculating activated yeast into the fermentation barrel, and fermenting for 9 days;

[0057] S233: controlling the temperature of the fermentation barrel at 25±1° C., adding lactic acid bacteria into the fermentation barrel to perform malic acid-lactic acid fermentation;

[0058] S24: sampling and testing the liquid in the fermentation barrel, and when it is detected that the specific gravity of the liquid in the fermentation barrel is lower than 1.010, it is determined that the fermentation of the whole grapes is complete;

[0059] S25: The fermented whole grapes are pressed and the skins and residues are separated to terminate the malic acid-lactic acid fermentation.

[0060] Embodiments 2 to 7

[0061] The difference between Examples 2 to 6 and Example 1 is the amount of added substances in each step and the process control. The difference is that the proportion of each substance added in the peel protection solution of Examples 2 and 3 is different from that of Example 1, amino acid chelated calcium is also added to the peel protection solution in step S1 of Example 4 as a calcium agent, and the soaking time in the peel protection solution of Examples 5 and 6 is different from that of Example 1. Furthermore, in step S23 of Example 7, the grapes after destemming are further screened for a second time, and the broken part of the whole grapes is controlled to be no more than 15% and added to the fermentation barrel in layers with the intact part.

[0062] Comparative Example 1

[0063] The difference between Comparative Example 1 and Example 1 is that Comparative Example 1 does not perform step S21, that is, does not perform skin protection treatment, and only performs grape cleaning treatment. The other steps are the same as those in Example 1.

[0064] Comparative Example 2

[0065] The difference between Comparative Example 2 and Example 1 is that the soaking time in step S21 is only 5 minutes. The other steps are the same as those in Example 1.

[0066] Comparative Example 3

[0067] The difference between Comparative Example 3 and Example 1 is that the soaking time in step S21 is 40 minutes. The other steps are the same as those in Example 1.

[0068] Comparative Example 4

[0069] The difference between Comparative Example 3 and Example 1 is that, in step S23, Comparative Example 3 further performs secondary screening on the de-stemmed grapes, and controls the broken parts in the whole grapes to account for 25% of the total grapes.

[0070] The control parameters of each step of Examples 2 to 7 and Comparative Examples 1 to 4 are detailed in Tables 1 and 2.

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

[0072]

[0073]

[0074] Table 2 Parameter configuration of each step of comparative examples 1 to 4

[0075]

[0076] The total content of phenolic substances and the content of tannin in the wine obtained after the fermentation was terminated in step S23 in the above embodiments and comparative examples were measured by spectrophotometry. The measurement results are shown in Table 3 below.

[0077] Table 3 Measurement results of various embodiments and comparative examples

[0078]

[0079]

[0080] It can be seen from the above Example 1 and Comparative Example 1 that the use of complete skin protection and whole-grain fermentation process during the fermentation process can significantly reduce the tannin content in the wine.

[0081] It can be seen from the above Examples 1 and 4 that adding calcium agent to the peel protection solution can further enhance the peel strength and reduce the increase in tannin content caused by peel rupture during the fermentation process.

[0082] 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 effect on the fermentation of grapes. It is speculated that the soaking time is too short, and the protective layer cannot be effectively formed, resulting in the peel being broken during the subsequent treatment process, releasing more inferior tannins. If the soaking time is too long, the release of tannins cannot be significantly reduced. Therefore, considering the production efficiency, the soaking time is controlled to 10-30 minutes.

[0083] It can be seen from the above Examples 1, 5, 7 and Comparative Example 4 that adding excessive amounts of crushed parts without adding them in layers during whole grain fermentation will lead to an increase in the tannin content, while adding an appropriate amount of crushed parts will not have much impact on the increase in tannin content.

[0084] It can be seen from the above embodiments, comparative examples and experimental conclusions that the cold-soaked whole-grain grape fermentation method provided by the present application can effectively solve the problem that the grape skin will inevitably break during the fermentation process in the existing grape fermentation method, causing inferior tannins to enter the wine and adversely affecting the flavor of the wine, by protecting the grape skin before fermentation. It is easy to promote and apply in actual production. It can be further seen that the beneficial effects of the present application are significant.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A grape cold soaking whole grape fermentation method, characterized in that: include: Putting the whole bunch of grapes into a peel protection liquid and soaking it for 10 to 30 minutes and then taking it 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 includes cellulose and pectin in a mass ratio of 3 to 5:1; Drying the whole bunch of grapes, removing the stems and grape cores of the whole bunch of grapes after drying, to obtain whole grapes; adding the whole grapes into a fermentation barrel, and sequentially performing low-temperature immersion treatment, alcohol fermentation treatment and malic acid-lactic acid fermentation treatment in the fermentation barrel; The whole grapes that have completed fermentation are pressed and the skins and pulp are separated to terminate the malolactic fermentation.

2. The grape cold soaking whole grape fermentation method according to claim 1, characterized in that: The cellulose includes at least one of sodium carboxymethylcellulose, microcrystalline cellulose and hydroxypropyl cellulose.

3. The grape cold soaking whole grape fermentation method according to claim 1, characterized in that: The solvent includes water.

4. The method for cold soaking and whole grape fermentation according to any one of claims 1 to 3, characterized in that: The peel protective agent comprises cellulose, pectin and calcium agent in a mass ratio of 3-5:1:1-3.

5. The whole grape cold soaking and fermentation method according to claim 1, characterized in that: The broken parts in the whole grapes do not exceed 15%.

6. The method for cold soaking and whole grape fermentation according to claim 5, characterized in that: The step of adding whole grapes into the fermentation barrel comprises: The intact part and the crushed part of the whole grapes are added to the fermentation tank in layers.

7. The whole grape cold soaking and fermentation method according to claim 1, characterized in that: The step of soaking the whole bunch of grapes in the peel protection liquid for 10 to 30 minutes and then taking them out comprises: Within 3 days before fermentation, soak the whole bunch of grapes in the skin protection solution for 10 to 30 minutes and then take them out.

8. The method for cold soaking and whole grape fermentation according to claim 1, characterized in that: The low-temperature impregnation treatment comprises: Fill the fermentation barrel with a portion of carbon dioxide gas, add the whole grapes into the fermentation barrel, continue to fill with carbon dioxide gas until it is full, seal the fermentation barrel, and continue low-temperature immersion for 10 to 15 days.

9. The whole grape cold soaking and fermentation method according to claim 1, characterized in that: The alcohol fermentation process comprises: The activated yeast is inoculated into the fermentation barrel and fermented for 7 to 10 days.

10. The method for cold soaking and whole grape fermentation according to claim 1, characterized in that: Before the whole grapes that have completed fermentation are pressed and the skin and residue are separated, the method further comprises: The liquid in the fermentation barrel is sampled and tested, and when it is detected that the specific gravity of the liquid in the fermentation barrel is between 0.990 and 1.000, it is determined that the fermentation of the whole grapes is completed.

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