A method for brewing fig liqueur

Abstract

This invention belongs to the field of fruit processing, specifically disclosing a method for brewing fig liqueur. This method involves treating fig pulp with pectinase and fructase to obtain clear juice, followed by temperature gradient fermentation, pre-fining clarification, and oak barrel aging. These processes effectively enhance the aroma of the fig wine, fully utilize the flavor and nutritional advantages of figs, resulting in a richer taste. Simultaneously, the stability of the fig wine is improved, significantly extending its shelf life.

Description

Technical Field

[0001] This invention belongs to the field of fruit processing technology, specifically relating to a method for preparing fig liqueur. Background Technology

[0002] Figs, as a fruit used in both food and medicine, are rich in various nutrients, such as vitamins, minerals, dietary fiber, and unique bioactive components. They offer numerous health benefits, including clearing heat and moisturizing the intestines, protecting the liver, and enhancing the body's immune function. In recent years, with the increasing awareness of health, there has been growing interest in the development of fig-related products.

[0003] In the fruit wine industry, fig wine has been extensively researched and produced. Traditional fig wine is generally made from fig juice or pulp through yeast fermentation. The brewing process typically includes steps such as raw material selection, washing, stem removal, cutting, color preservation, pulping, component adjustment, sterilization, inoculation and fermentation, filtration, aging and clarification. However, existing fig wines have some limitations: 1) Limited flavor: Most fig wines rely mainly on the fermentation flavor of the figs themselves, making it difficult to meet the diverse taste needs of different consumers.

[0004] 2) Poor stability and short shelf life: Fig wine is prone to sedimentation, layering and flavor changes during storage, which affects product quality and market acceptance.

[0005] Fig liqueurs and fig wine are distinctly different. Fig wine is primarily made through fermentation, converting the sugars in figs into alcohol; while fig liqueurs are typically made by blending and aging a base of fermented fig wine with added distilled spirits, flavorings, and plant extracts. Currently, there is limited research and production of fig liqueurs on the market, making it difficult to fully utilize the flavor and nutritional advantages of figs and to develop a unique and consumer-friendly product style.

[0006] Current fig wine extraction processes suffer from several problems: 85°C temperature inactivation of enzymes, combined enzymatic hydrolysis with pectinase and pectinase, multiple centrifugal removal devices, a single fermentation temperature, limited aging equipment, and complex and large-volume use of clarifying agents. The 85°C temperature inactivation of enzymes results in high-temperature loss of fruit aroma; the combined use of pectinase and pectinase leads to high dosage and low juice yield. Using pre-hydrolysis with pectinase followed by pectinase can reduce enzyme dosage and increase juice yield by approximately 5%; the additional centrifugal removal equipment increases the risk of juice oxidation, causing subsequent aroma loss; the single fermentation temperature results in a limited range of aroma types, with different fermentation temperatures producing different types of lipid aromas; simple fermentation tank aging does not add additional aromas, but aging in different oak barrels can provide different toasty and nutty aromas; the use of compound clarifying agents is large, precipitating unstable substances and some aromatic compounds. Adding clarifying agents during fermentation and early fining can significantly improve the quality of the fig wine.

[0007] Addressing the shortcomings of existing fig wines and fig liqueurs, this invention aims to provide a novel fig liqueur and its preparation method. Through unique raw material processing, fermentation technology, and precise blending and aging techniques, it solves the problems existing in commercially available products, developing a fig liqueur with adjustable alcohol and sweetness, unique flavor, rich nutrition, and good stability to meet the market demand for high-quality specialty fruit wines. Summary of the Invention

[0008] The purpose of this invention is to overcome the above-mentioned shortcomings and provide a method for brewing fig liqueur. This fig liqueur is made from fresh figs, which solves the problems of poor stability and difficulty in storage, while also increasing the diversity of fig wine products.

[0009] The objective of this invention is achieved through the following means: A method for producing fig liqueur, comprising the following steps: S1: Preparation of fig pulp: Fresh or frozen figs are washed, crushed by a double-stage pulper, and then ground by a colloid mill to obtain fig pulp. Potassium metabisulfite is added during the crushing process. S2: Enzymatic hydrolysis: Add fruit pulp enzyme to fig pulp sequentially and hydrolyze at room temperature for 30-60 minutes, then add pectinase and hydrolyze at 50℃ for 1-2 hours to obtain the hydrolysate; the amount of fruit pulp enzyme and pectinase added is 0.05kg / T-0.2kg / T; S3: Centrifugation to remove impurities: Separate and remove impurities from the enzymatic hydrolysate to obtain fig juice; S4: Adjusting Fermentation: Adjusting the physicochemical properties of fig juice, inoculating with brewing yeast, and controlling the temperature for fermentation; after fermentation starts, adding bentonite to the original wine for clarification during fermentation. S5: Termination of fermentation: When the fig wine ferments to an alcohol content of 5-10° and the residual sugar is 60-120g / L, add fig brandy to adjust the alcohol content to 15-22° and terminate the fermentation. S6: Aged: The clarified original spirit is aged and matured in oak barrels; S7: Freeze Filtration: After aging, the original wine is frozen and filtered to obtain the finished fig liqueur.

[0010] Preferably, in step S1, the amount of potassium metabisulfite added is 0.1-0.2 kg / T based on the weight of the figs.

[0011] Preferably, in step S3, the turbidity of the fig juice is controlled at 40-100 ntu.

[0012] Preferably, in step S4, the physicochemical properties of the fig juice are adjusted as follows: the amount of white sugar added is 40-120 kg / T, and the amount of naturally extracted tartaric acid added is 0.5-1 kg / T.

[0013] Preferably, in step S4, brewer's yeast is inoculated at a rate of 0.25-0.3 kg / T, the fermentation temperature is controlled at 14-18℃, and the fermentation cycle is 3-10 days.

[0014] More preferably, during the fermentation process of inoculated brewer's yeast, the temperature is controlled at 14°C when the specific gravity is above 1.080, at 16°C when the specific gravity is between 1.080 and 1.060, and at 18°C ​​when the specific gravity is between 1.060 and 1.050.

[0015] Preferably, in step S5, fermentation is terminated, and fig brandy with an alcohol content of 65-70° is added. The amount added is adjusted according to the fermentation alcohol content of the fig wine, so that the final product has an alcohol content of 15-20° and a residual sugar content of 60-120g / L.

[0016] Preferably, in step S4, the amount of bentonite added is 0.5-1.0 kg / T, and the addition time is within 12-24 hours after the yeast is added, and the addition is observed after the fermentation starts.

[0017] Preferably, in S6, the aging process involves using fine-grained, medium-grained, or wide-grained oak barrels that have been lightly or moderately toasted, and aging for more than 2 years.

[0018] Preferably, in step S7, the original wine is frozen at -6°C for 7 days and filtered at 0.2μm while cold to obtain fig liqueur.

[0019] The advantages of this invention compared with the prior art are as follows: (1) Add potassium metabisulfite: Sterilization and preservation: Potassium metabisulfite decomposes into sulfurous acid in water. Sulfurous acid can inhibit the growth and reproduction of various microorganisms, effectively preventing fruit wine from being contaminated by miscellaneous bacteria during fermentation, ensuring the normal progress of fermentation, and also helping to extend the shelf life of fruit wine.

[0020] Antioxidant: Sulfurous acid has strong reducing properties and can react with oxygen in fruit wine, reducing the oxidation of nutrients and flavor substances in the fruit wine by oxygen, preventing the fruit wine from darkening in color and changing in flavor, and maintaining the color and taste of the fruit wine.

[0021] Clarifying effect: Potassium metabisulfite can combine with some colloidal substances in fruit wine, causing them to precipitate, thus making the fruit wine clearer and improving its appearance quality.

[0022] (2) Enzymatic hydrolysis by pulp enzymes and pectinases: By screening for specific pulp enzymes and pectinases to hydrolyze fig pulp, the pectin in the juice is effectively broken down, reducing the viscosity of the juice, causing suspended particles in the juice to settle, improving the clarity and filtration speed of the juice, and preserving the flavor characteristics of figs to the greatest extent.

[0023] (3) Fermentation of clear juice: Improved fermentation efficiency: The clear juice contains fewer impurities, allowing the yeast to fully contact with nutrients, resulting in more uniform and faster fermentation and effectively shortening the fermentation cycle.

[0024] Improved wine stability: Because the clear juice removes most of the pectin, protein and other substances that easily cause turbidity and precipitation, the fruit wine obtained after fermentation is more stable and less prone to turbidity and precipitation during storage and aging, which helps maintain the clarity and appearance quality of the wine.

[0025] Easy to control the fermentation process: The composition of clear juice is relatively simple and stable, which is conducive to accurately controlling fermentation conditions such as temperature, pH value, and sugar content, thereby better ensuring the smooth progress of the fermentation process and improving the consistency and quality control of the product.

[0026] Imparting a unique flavor: Clear juice fermentation can reduce some special flavor substances from the peel and pulp, giving the fruit wine a purer, more delicate taste and a unique flavor, highlighting the aroma of the fruit itself, and meeting consumers' needs for fruit wines with different flavors.

[0027] (4) Gradient fermentation: Enhancing flavor complexity: By controlling conditions such as temperature, sugar content, and yeast type at different stages of fermentation, fruit wine can produce a variety of flavor compounds during fermentation. For example, maintaining a lower temperature in the initial stage helps preserve the natural aroma of the fruit; as fermentation progresses, gradually increasing the temperature promotes the production of more esters, alcohols, and other flavor compounds by the yeast, resulting in a richer and more layered taste in the fruit wine.

[0028] Optimizing nutrient utilization: Different fermentation stages have different nutrient requirements. Gradient fermentation allows yeast to make fuller use of the sugars, nitrogen sources, vitamins, and other nutrients in the fruit. In the early stages of fermentation, yeast needs more nitrogen for growth and reproduction. As fermentation progresses, more sugar is converted into alcohol, achieving rational utilization of nutrients and improving the nutritional value and quality of the fruit wine.

[0029] (5) Apply glue in advance: Higher chroma values ​​result in brighter and richer colors; a more intense, cleaner, and fresher aroma; a stronger overall structure, but a relatively weaker astringency; and fruit wines treated with pre-fining are more drinkable.

[0030] (6) Add fig brandy: Enriched taste and flavor: Fig brandy has unique aromas and flavors, such as rich fruit, floral, vanilla and woody notes from aging, which can add complex layers to liqueurs, making them more rich and mellow.

[0031] Improving Quality and Stability: The addition of brandy can improve the quality of liqueurs, enhancing their color and clarity. Furthermore, due to the good stability of brandy, it helps improve the overall stability of the liqueur, reducing the possibility of sedimentation and spoilage. (7) Oak barrel aging: Adding flavor: Oak barrels contain a variety of flavor compounds, such as vanillin and eugenol, which are slowly released into the wine during aging, adding unique flavors such as toast, vanilla, smoke, and spices, and enriching the wine's taste.

[0032] Softening the taste: Oak barrels have a certain degree of permeability, allowing a suitable amount of oxygen to slowly enter the wine, causing the tannins in the wine to undergo a polymerization reaction, making the tannin structure more stable, thereby softening the taste of the wine, reducing bitterness and roughness, and making the wine more rounded and smooth.

[0033] Enhancing Color: The pigments and phenolic compounds in oak infuse into the wine, helping it to develop a richer, more appealing color. For example, red wines will become deeper and brighter, while white wines will take on a pale golden hue.

[0034] Stabilizing the wine: Some components in oak barrels can react with unstable substances in the wine, promoting clarification and stabilization, reducing the possibility of sedimentation or spoilage during storage, and extending the wine's optimal drinking window.

[0035] Therefore, the process of treating fig pulp with pectinase and sap extract to obtain clear juice, followed by temperature gradient fermentation, early fining and clarification, and oak barrel aging, provided by this invention, enhances the aroma of fig wine, fully utilizes the flavor and nutritional advantages of figs, enriches the taste, and improves the stability of fig wine, effectively extending its shelf life. Attached Figure Description

[0036] Figure 1 A comparison of the performance of pre-fining and post-fermentation fining in fig wine production.

[0037] Figure 2 Comparison of photos before and after stability tests of existing fig wine and the fig wine of this invention (A: before the experiment, B: 100 days later). Detailed Implementation

[0038] To enable those skilled in the art to better understand the present invention, the present invention will now be further described in conjunction with specific embodiments.

[0039] Example 1 (1) Take fresh figs, wash them in a washing machine, then put them into a double-stage pulping machine for crushing and then grind them in a colloid mill. During the crushing process, add potassium metabisulfite at a rate of 0.1 kg / T (based on the weight of the figs). (2) Enzymatic hydrolysis: Add pectinase to the fig pulp in (1) and hydrolyze at room temperature for 50 minutes, then add pectinase and hydrolyze at 50℃ for 1.5 hours.

[0040] (3) Centrifugation to remove impurities: The enzymatic hydrolysate from (2) is passed through a disc centrifuge to remove impurities and obtain fig juice with a turbidity of about 60 ntu.

[0041] (4) Adjustment and fermentation: The sugar content of the fig juice in (3) was 160 g / L and the total acid was 3.5 g / L. Based on the results, 1 g / L of naturally extracted tartaric acid was added, and 80 g / L of white sugar was mixed evenly. The activated dry white wine yeast rose was inoculated at an inoculation amount of 0.25 kg / T. The fermentation temperature was controlled at 14℃. According to the hydrometer test, when the specific gravity was above 1.080, the temperature was controlled at 14℃; when the specific gravity was 1.080-1.060, the temperature was controlled at 16℃; and when the specific gravity was 1.060-1.050, the temperature was controlled at 18℃. 0.5 kg / T of bentonite was added to the fig liqueur after the fermentation started, and the addition time was between 12-24 hours after the yeast was added.

[0042] (5) Termination of fermentation: After the fig wine in step (4) fermented for 5 days, the residual sugar was found to be 120g / L and the alcohol content was 6.8°. 19% of 65° fig brandy was added, filtered, and a fig liqueur with an alcohol content of 17.8° and a total sugar content of 97g / L was obtained.

[0043] (6) Aging: The liqueur juice obtained in step (5) is placed into different types of oak barrels with fine, medium, and wide textures and light or medium toasting, and aged for 2 years. All oak barrels are used to store the liqueur, which is then blended.

[0044] (7) Freezing and filtration: After mixing the original wines in step (6), freeze them at -6°C for 7 days, and filter them at 0.2μm while they are cold to obtain fig liqueur. Example 2

[0045] (1) Take fresh figs, wash them in a washing machine, then put them into a double-stage pulping machine for crushing and then grind them in a colloid mill. During the crushing process, add potassium metabisulfite at a rate of 0.2 kg / T (based on the weight of the figs). (2) Enzymatic hydrolysis: Add pectinase to the fig pulp in (1) and hydrolyze at room temperature for 50 minutes, then add pectinase and hydrolyze at 50℃ for 1 hour.

[0046] (3) Centrifugation to remove impurities: The enzymatic hydrolysate from (2) is passed through a disc centrifuge to remove impurities and obtain fig juice with a turbidity of about 80 ntu.

[0047] (4) Adjustment and fermentation: The sugar content of the fig juice in (3) was 150 g / L and the total acid was 4 g / L. Based on the results, 0.5 g / L of naturally extracted tartaric acid was added, and 90 g / L of white sugar was mixed evenly. The activated dry white wine yeast rose was inoculated at an inoculation amount of 0.25 kg / T. The fermentation temperature was controlled at 14℃. According to the hydrometer test, when the specific gravity was above 1.080, the temperature was controlled at 14℃; when the specific gravity was 1.080-1.060, the temperature was controlled at 16℃; and when the specific gravity was 1.060-1.050, the temperature was controlled at 18℃. 0.5 kg / T of bentonite was added to the fig liqueur after the fermentation started, and the addition time was between 12-24 hours after the yeast was added.

[0048] (5) Termination of fermentation: After the fig wine in step (4) fermented for 5 days, the residual sugar was found to be 110g / L and the alcohol content was 7.6°. 18% of 65° fig brandy was added, filtered, and a fig liqueur with an alcohol content of 18° and a total sugar content of 90g / L was obtained.

[0049] (6) Aging: The liqueur juice obtained in step (5) is placed into different types of oak barrels with fine, medium, and wide textures and light or medium toasting, and aged for 2 years. All oak barrels are used to store the liqueur, which is then blended.

[0050] (7) Freeze-filtration: After mixing the original wines in step (6), freeze at -6°C for 7 days, and filter at 0.2μm while still cold. You can then obtain fig liqueur.

[0051] Experimental Example 1: Stability Test Methods: Three incubators were placed alternately every week, with a low temperature of -5℃, a high temperature of 40℃, and strong light of 4500lx, to simulate whether winter and summer and light exposure would cause precipitation and discoloration. The experimental results are shown in Table 1.

[0052] Table 1

[0053] Experiment Example 2: Taste Evaluation Comparison Experiment Comparative Example 1: The pulp enzyme in step (2) of Example 1 was replaced with pectin lyase, and other conditions were the same as in Example 1.

[0054] Comparative Example 2: The clarification step in Example 1 was changed to a combined clarification process after fermentation by adding multiple clarifying agents: 0.5 g / L bentonite, 0.3 g / L PVPP, and 0.3 g / L plant protein were used as clarifying agents. The clarifying agents were added one week after fermentation, and the clear juice was separated two weeks after the clarifying agents were added.

[0055] Comparative Example 3: The gradient temperature fermentation in step (4) of Example 1 was changed to fermentation at a uniform temperature of 18°C, and other conditions were the same as in Example 1.

[0056] Comparative Example 4: The step (6) in Example 1 was changed to aging in a single fine-grained lightly toasted oak barrel for 2 years instead of fine-grained, medium-grained, and wide-grained oak barrels for 2 years.

[0057] Comparative Example 5: Existing fig wine products on the market.

[0058] The six finished products of Example 1 and Comparative Examples 1-5 were tasted and compared with each other with a maximum score of 10. Five tasters scored the samples.

[0059] The taste evaluation criteria were based on the "China Wine Evaluation System" jointly released in 2018 by the China Alcoholic Drinks Association, the China National Food Industry Association, and the Chinese Society for Horticultural Science. The results are shown in Table 2. Table 2

[0060] Example 1 9.5 9.2 9.3 9.2 9.4 9.32 Comparative Example 1 9.2 9.1 9.3 9.0 9.1 9.14 Comparative Example 2 8.5 8.7 9.1 8.9 9.0 8.84 Comparative Example 3 8.2 8.5 8.6 8.5 8.6 8.48 Comparative Example 4 9.0 8.9 9.0 8.8 9.0 8.94 Comparative Example 5 8.0 7.9 8.1 7.8 8.0 7.96 According to the tasters' comparison, Example 1 has a rich fruity aroma, is sweet but not cloying, has a complex flavor profile, a balanced body, and is more widely accepted by the general public.

[0061] Experiment Example 3: Shelf Life Test I. Experimental Objective By comparing the changes in sensory quality physicochemical indicators and microbiological indicators of fig liqueur (Product of Example 1) and fig wine (commercially available product) during storage, the actual difference in shelf life between the two products was verified.

[0062] II. Experimental Materials and Instruments 1. Experimental Samples Sample A: Fig Liqueur (Product from Example 1) Sample B: Fig Wine (Commercially Available Product) 2. Instruments and reagents Constant temperature and humidity incubator, colorimeter, pH meter, alcohol content measuring device, total bacterial count petri dishes, aseptic workbench, sealed light-proof storage container, sensory evaluation cups III. Experimental Conditions Accelerated shelf testing conditions: temperature 37℃, relative humidity 65% ​​(accelerated aging of room temperature shelves, 1 day ≈ 3.5 days at room temperature); Experiment duration: 45 days; Sampling nodes: 0d, 15d, 30d, 45d.

[0063] IV. Experimental Detection Indicators 1. Sensory indicators: color, clarity, aroma, taste, sedimentation / turbidity. 2. Physicochemical properties: pH, total acidity, color difference, volatile acidity 3. Microbiological indicators: total bacterial count, mold and yeast count V. Detailed Experimental Procedure Step 1: Sample Pretreatment 1. Take 3L of sample A and sample B respectively, and divide them into sterile, light-proof, sealed bottles. Make 3 replicates for each group and label them. 2. Place all samples in a 37℃ constant temperature and humidity incubator and store them in the dark.

[0064] Step 2: Regular sampling and testing 1. Initial 0d Two groups of samples were taken separately and subjected to blind sensory evaluation to measure pH, total acid, color difference, and volatile acid. Samples were taken under aseptic conditions to detect total bacterial count and mold and yeast count, and the raw data were recorded.

[0065] 2. Mid-term 15d, 30d Following the same procedure, samples were taken at regular intervals, and sensory evaluation, physicochemical and microbiological testing were repeated to observe whether the wine showed signs of turbidity, suspended matter, sediment, discoloration, or off-odors.

[0066] 3. 45 days in the final stage Complete all indicator tests, compare the changes of the two groups of samples throughout the process, and summarize the data.

[0067] Step 3: Data Recording and Analysis By compiling data from various time points and comparing the rate of decay and degree of deterioration of the two groups of samples, the differences in shelf stability can be determined.

[0068] Experimental results The sensory evaluation results are shown in Table 3. Table 3 0d The wine is clear and bright, with a light amber color. It has a pure fig aroma, a mellow and harmonious taste, and no off-flavors or sediment. The wine is clear, with a fresh fruity aroma and a crisp taste. There is no cloudiness or sediment, and its initial sensory characteristics are not significantly different from A. 15d The color showed no significant change; the wine was clear; the aroma was intact; and the taste was stable. Slight darkening of color, diminished fruit aroma, and slight loss of luster in the wine. 30d The color is uniform, without turbidity or precipitation, and the aroma and taste show no deterioration. The wine has turned noticeably brown, become cloudy, and developed fine white sediment. The fruit aroma has faded, and there is a slightly rancid aftertaste. 45d The wine is stable with no layering or sediment, and its color and flavor remain largely unchanged from their initial state. Severe browning, obvious stratification, large amount of flocculent precipitate, prominent sour and rancid taste, and completely deteriorated flavor. Core data of physicochemical indicators 1. pH value Fig liqueur (Product of Example 1): 0d (3.62) → 45d (3.58), with minimal fluctuations and a stable system; Fig wine (commercially available product): 0d (3.60) → 45d (3.21), acidity increased significantly, and fermentation byproducts increased.

[0069] 2. Color difference / browning The browning index of the sample fig liqueur (product of Example 1) increased by less than 5%; The browning index of the sample fig wine (commercially available product) increased by more than 28%, indicating severe oxidation of phenolic substances.

[0070] 3. Volatile acids The sample fig liqueur (product of Example 1) maintained a low level throughout the process, below 0.5 g / L, with no spoilage or fermentation. The sample of fig wine (commercially available product) had excessive volatile acidity, increasing from 0.3g / L to 1.6g / L, and had a prominent sour smell.

[0071] 4. Microbiological Indicator Results The sample fig liqueur (product of Example 1) and fig wine (commercially available product): within 45 days, the total bacterial count and mold and yeast count both met the national standard limits for fruit wine, and there was no growth of miscellaneous bacteria; VII. Experimental Conclusions 1. Under accelerated aging conditions at 37℃, the sample fig liqueur (product of Example 1) exhibits stable physicochemical system, controllable microorganisms, no sensory deterioration, strong antioxidant and antibacterial capabilities, and long-term storage capability. 2. The sample fig wine (commercially available product) is prone to oxidative browning, microbial growth, flavor spoilage and precipitation, and has poor storage stability, making it only suitable for short-term preservation and sales. 3. This experiment effectively verifies that there is a significant difference in the shelf life of the two fig wines, and can be used as experimental proof that the sample fig liqueur (product of Example 1) has a longer shelf life.

Claims

1. A method for brewing a fig liqueur, comprising the following steps: S1: Preparation of fig pulp: Fresh or frozen figs are washed, crushed by a double-stage pulper, and then ground by a colloid mill to obtain fig pulp. Potassium metabisulfite is added during the crushing process. S2: Enzymatic hydrolysis: Add fruit pulp enzyme to fig pulp sequentially and hydrolyze at room temperature for 30-60 minutes, then add pectinase and hydrolyze at 50℃ for 1-2 hours to obtain the hydrolysate; the amount of fruit pulp enzyme and pectinase added is 0.05kg / T-0.2kg / T; S3: Centrifugation to remove impurities: Separate and remove impurities from the enzymatic hydrolysate to obtain fig juice; S4: Adjusting Fermentation: Adjusting the physicochemical properties of fig juice, inoculating with brewing yeast, and controlling the temperature for fermentation; after fermentation starts, adding bentonite to the original wine for clarification during fermentation. S5: Termination of fermentation: When the fig wine ferments to an alcohol content of 5-10° and the residual sugar is 60-120g / L, add fig brandy to adjust the alcohol content to 15-22° and terminate the fermentation. S6: Aged: The clarified original spirit is aged and matured in oak barrels; S7: Freeze Filtration: After aging, the original wine is frozen and filtered to obtain the finished fig liqueur.

2. The method of claim 1, wherein the noyaux is added to the mixture of figs, water and sugar in an amount of 0.1 to 0.3% by weight of the figs. In S1, the amount of potassium metabisulfite added is 0.1-0.2 kg / T based on the weight of figs.

3. The method for brewing fig liqueur as described in claim 1, characterized in that, In step S3, the turbidity of the fig juice is controlled at 40-100 ntu.

4. The method for brewing fig liqueur as described in claim 1, characterized in that, In step S4, the physicochemical properties of fig juice are adjusted as follows: the amount of white sugar added is 40-120 kg / T, and the amount of naturally extracted tartaric acid added is 0.5-1 kg / T.

5. The method for brewing fig liqueur as described in claim 1, characterized in that, S4 is inoculated with brewer's yeast at a rate of 0.25-0.3 kg / T, the fermentation temperature is controlled at 14-18℃, and the fermentation cycle is 3-10 days.

6. The method for brewing fig liqueur as described in claim 5, characterized in that, During the fermentation process with inoculated Saccharomyces cerevisiae, it was found that the temperature was controlled at 14℃ when the specific gravity was above 1.080, at 16℃ when the specific gravity was between 1.080 and 1.060, and at 18℃ when the specific gravity was between 1.060 and 1.

050.

7. The method for brewing fig liqueur as described in claim 1, characterized in that, Fermentation is terminated in step S5, and fig brandy with an alcohol content of 65-70° is added. The amount added is adjusted according to the fermentation alcohol content of the fig wine, so that the final product has an alcohol content of 15-20° and a residual sugar content of 60-120g / L.

8. The method for brewing fig liqueur as described in claim 1, characterized in that, In S4, the amount of bentonite added is 0.5-1.0 kg / T, and the addition time is between 12-24 hours after the yeast is added. The addition is observed after the fermentation starts.

9. The method for brewing fig liqueur as described in claim 1, characterized in that, In S6, the aging process involves using fine-grained, medium-grained, and wide-grained oak barrels that have been lightly or moderately toasted, and aging for more than 2 years.

10. The method for brewing fig liqueur as described in claim 1, characterized in that, In step S7, the original wine is frozen at -6°C for 7 days and filtered at 0.2μm while cold to obtain fig liqueur.

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