01.
Concept and origin.
Fruit containing a certain amount of sugar and water, after crushing (crashing), pressing for juice (juice\must), fermentation (fermentation) or immersion and other processes carefully blended and brewed from a variety of low-grade beverage wine called fruit wine. China is generally named after the name of the raw material of the fruit, such as wine, cider, etc.;. At the same time, foreign countries believe typically that only wine is called wine (wine), others such as apple wine for cider, pear wine called perry, etc., of which wine is the most popular, is an international beverage wine, so we take wine as an example to tell.
It originated in ancient Egypt 5000 years ago and spread to Greece 2000 years ago to become the first country in Europe to make wine, then spread to Rome, with the expansion of the Roman Empire and expanded to France, Spain, Germany, the 9th century to Britain, the 10th century to Denmark and other northern European countries. In the early 18th century, Spanish immigrants brought European grapes to Mexico and other countries and then to California in the United States.
The region with the most significant production in Europe and the most extensive show are Italy, France, Spain, Argentina, the United States, Portugal, Romania and other countries. Italy and France have the most significant production, both in the 7-8 million tons.
Countries with high wine consumption are France, Italy, Argentina, Spain, Switzerland, Austria and other countries. Italy and France have a per capita consumption of more than 110 litres.
China began to brew wine from the Western Han Dynasty, such as the Han Dynasty when Emperor Wu was 800 years ahead of France. The quality of wine became better in the Eastern Han Dynasty, Three Kingdoms and Tang Dynasty, such as the “Liangzhou Lyrics.” The ruler of the Yuan Dynasty stipulated that wine had to be used for the worship of the Imperial Temple, which shows its importance, and the “Compendium of Materia Medica” of the Ming Dynasty gave a detailed introduction to the brewing and role of wine. 1892 was when Mr. Zhang Bishi started China’s The national wine industry was started by Mr. Zhang Bishi in 1892.
While China has a long history of wine production, its production has always been low. Until 1965, the annual output did not exceed 10,000 tons, and the proportion of high-grade wine was negligible, while the proportion of low-grade wine was large.
In 1994, the state revised and promulgated national standards for full-juice wine products containing 100% juice and industry standards for more than half-juice while requiring the elimination of production of wines containing less than 50% juice. Subsequently, the annual production of wine remained at about 200,000 tons. In 1999, the annual production of wine reached about 250,000 tons. The product mix of wine has also changed fundamentally; before 1995, sweet wines dominated, and dry wines were less common. In recent years, dry wine has grown at a rate of 50%. Now the proportion of dry wine in the total wine has increased to 40%. High-grade sparkling wine and single-variety fermented high-grade wine have been introduced one after another. At present, China’s wine market has achieved a high degree of brand concentration, of which only three brands – Zhang Yu, Great Wall and Dynasty – occupy half of the domestic wine market, with Zhang Yu’s share being 19.82%, making it the leader of China’s wine industry. In 2000, China’s high-quality grape base had reached 380,000 mu, an increase of nearly 80,000 mu compared with 1999. It further creates conditions for preferential selection of raw materials and cost reduction for future winemaking. The Chinese market has great potential, and it is expected that within 2010, China’s demand for wine will be about 800,000 tons, of which high-grade wine will account for 50%, mid-range wine for 40%, and low-grade wine for 10%.
There is an oversupply of wine worldwide, competition is fierce, and quality needs to be improved.
1. Global soft drink market demand is strong
02.
Overview of wine grape production areas in China
In the vast area of 45°-25°N latitude in China, there are grape and wine production areas with different characteristics. Still, due to the specific ecological environment needed for grape growth and the difference in the degree of regional economic development, the scale of these production areas is smaller and more scattered, mostly in eastern China. The distribution of significant wine grape production areas.
1. Northeast Origin Including the foothills of the Changbai Mountains south of 45° and the Northeast Plain, mainly in the area of Jilin and Liaoning, around 420 north latitude. Here the winter is severe, the temperature -30 – 40 ℃, the annual active temperature (≥ 10.) 2567-2779 ℃, precipitation 635-679 mm, the soil is black calcium soil, more fertile. Under the cold conditions in winter, European species of grapes (V. vinifera) cannot survive. In contrast, wild mountain grapes (V. amurensis) have become the main species cultivated here because of their extreme cold resistance. According to the statistics of 1960, the number of wild grapes harvested in Northeast China was about 1,000. At that time, the total amount of wild mountain grapes harvested in the Northeast reached 1.5 million tons, mainly used for winemaking. It is a model of mountain wine, such as the Red Plum brand of Jilin Tonghua Winery.
2. The origin of Bohai Bay includes the hilly mountains of Changli and Jixian in the northern half of North China, the Tianjin coastal area, the hills of the north of Shandong Peninsula and the Dazhe Mountains, i.e. the Changli production area, the Tianjin production area and the Jiaodong Peninsula, about 400 north latitude. Here, due to its proximity to Bohai Bay and the influence of the ocean, it is rich in heat and abundant in rainfall, with an annual activity temperature of 3756-4174℃, yearly precipitation of 5560-670mm and complex soil types, including sandy loam, seaside saline soil and brown loam. The ideal natural conditions make this place the most famous wine grape producing area in China, among which Cabernet Sauvignon from Changli, Rose Fragrance from Binhai District of Tianjin, Chardonnay, Guinness, Cabernet Sauvignon, Cabernet Franc, Serpentine, Merlot, Carignan, and White Yoni from the Shandong Peninsula is famous in China. The origin of Bohai Bay is the largest area and the best variety of wine grapes planted in China at present. Wine production accounted for 1/2 of the total national production. Dynasty in Tianjin, Zhang Yu in Shandong, Beijing’s night light cup, harvest, etc.
3. Shacheng origin Including Xuanhua, Zhuolu, Huailai, that is Huai Zhuo basin, about 40.50 north latitude. It is located north of the Great Wall, with sufficient light and moderate heat. The temperature difference between day and night is significant; the summer is fantastic, the climate is dry, the rainfall is low, the annual active temperature is 3532℃, the yearly precipitation is 413mm, the soil is brown, the texture is sandy. There are many hills and mountains, which are very suitable for the growth of grapes. Longan and milk grapes are the specialties here. In recent years, Cabernet Sauvignon, Merlot and other world-famous winemaking species have been promoted. Such as Great Wall, Martin, Rongchen, Spadone, etc.
4. Qingxu Origin Including Fenyang, Yuzi and Qingxu in the mountainous region of northwest Shanxi, around 37.5-380 N. The climate here is warm and relaxed, with plenty of light, the annual active temperature of 3000-3500°C, precipitation of 445mm, and soil of loam, sandy loam with gravel. Grapes are cultivated in mountainous areas with intense colouring. Longan of Qing Xu is a local specialty. In recent years Cabernet Sauvignon and Merlot have also been used for winemaking.
5. Yinchuan Origin Including the vast alluvial plain along the eastern foot of the Helan Mountains and other areas of Ningxia, latitude 38-390 N. Here, the weather is arid, the temperature difference between day and night is significant, the annual active temperature is 3298-3351℃, the annual precipitation is 180-200mm, the soil is sandy loam with gravel, the soil layer is 30-100mm. -This is the most extensive newly developed wine grape base in Northwest China, with the world’s leading wine varieties Cabernet Sauvignon and Merlot. Such as Ningxia Imperial Horse, Hengsheng Xixia King, etc.
6. Wuwei origin Including Wuwei, Minqin, Gulang, Zhangye and other areas of Gansu, about 36-400 north latitude, that is, the western corridor of the river, is located in the Tengri Great Desert edge of the county, but also an emerging wine production area on the Silk Road in China. Here the climate is cool and dry, annual activity temperature 2800-3000 ℃, annual precipitation 110 mm, due to the lack of heat, cold winters, suitable for the growth of early and medium-ripening grape varieties, in recent years has developed Merlot, Pinot Noir, Chardonnay and other types. Such as Mogao Industry, Su Wu Manor, Liangzhou Huangtai, etc.
The Tulufan production area includes Shanshan in the Tulufan basin, which is 300 meters below sea level, and the Red Willow River, which is around 430 north latitude, surrounded by mountains and frequent hot winds, with extremely high temperatures in summer, reaching over 45°C and an annual activity temperature of 5319°C. Rainfall is scarce, with only 16.4mm throughout the year, and this is the base for the production and drying of seedless white grapes in China. More than ten years ago, Guo Qichang, a famous wine expert, planted Cabernet Sauvignon, Merlot, Grenache, Syrah, Zoetin and other winemaking grapes here on a trial basis. Although the glucose level is high, the acidity is low, the fragrance is insufficient, and the dry wine quality is poor. In contrast, the sweet wine produced has western characteristics. The quality is still good, such as Xintian International Wine Industry, Xinjiang Western Wine Industry, Xinjiang Lou Lan Wine Industry.
8. The origin of the Old Yellow River Road, Including Xiao County of Anhui, Lankao of Henan, Minquan and other counties in the Old Yellow River Road, about 34.5-350 north latitude, which is also along the railroad line of Zhengzhou-Xuzhou, where the climate is on the hot side, with an annual activity temperature of 4000-4590℃. The yearly precipitation is over 800mm and is concentrated in summer. Hence, the grapes thrive, with severe diseases and reduced quality. In recent years, some wineries have developed new winemaking bases and improved cultivation techniques by introducing late-maturing varieties such as Cabernet Sauvignon. The prevalence of diseases has been basically controlled, and the quality of grapes is expected to improve.
9. Yunnan plateau production areas include Mile, Dongchuan, Yongren and Panzhihua on the Jinsha River at the border of Sichuan and Yunnan at an altitude of 1,500 meters above sea level, with the soil of primarily red and brown loam at about 21-290 north latitude. The climate here is characterized by abundant light, heat and timely precipitation, with a distinct dry season from October-November of the previous year to June of the following year, with 329mm (Mile in Yunnan) and 100mm (Panzhihua in Sichuan) of precipitation suitable for the growth and ripening of wine grapes. The cultivation of Eurasian species of grapes using the natural advantage of this unique microclimate in the dry season has become a significant feature of southwestern viticulture. For example, Yunnan Wine Industry, Shangri-La Wine Industry, Shenquan Wine Industry, etc.
The above nine production areas have undergone decades of development before gradually forming. It constructs the basic framework of wine grape production areas in China in the 21st century.
03.
The status and characteristics of wine.
1, in line with the development direction of China’s wine industry.
High-level wine – low-level wine
Grain wine — fruit wine
Distilled spirits — brewing wine
Ordinary wine — quality wine
2.It is rich in nutrition, with anti-disease and preventive effects.
3.The colour, aroma and taste are distinctive.
4.Cultivated or wild fruits as raw materials can save food.
04.
Classification of wine.
1.Classified by the colour of wine (colour).
(1) white wine (white wine): fermented from white grapes or grapes with red skin and white flesh, the colour of the wine is slightly yellow with green, almost colourless or light yellow, straw yellow, etc.
(2) Red wine (red wine): made from a mixture of red skin and white skin or red skin and fermented grapes with a light colour of deep ruby red, ruby red or purple-red, garnet red.
(3) rosé wine (pink wine): made from coloured red grapes with skin fermentation or separate fermentation. The colour of the wine is light red, rosé rose.
2. Sugar content (sugar) how much classification.
(a) Dry wine: the sugar content is less than 4g/L, and the sweetness is not tasted, and it is divided into dry white, dry red and dry rosé.
(b) Semi-dry wine: sugar content of about 4-12 g/L, slightly sweet, also divided into semi-dry white.
(c) Semi-sweet wine: sugar content of about 12-50 g/L, with sweetness.
(d) Sweet wine (sweet wine): the sugar content is more than 50 g/L, with sweetness and mellow.
3. Classified according to whether it contains CO2.
(1) Still wine: wine that does not contain its own alcohol or artificially added CO2.
(2) Sparkling wine and sparkling wine: Contains some CO2.
A. Sparkling wine (sparkling wine): CO2 is produced by adding sugar to wine and fermenting it. The sparkling wine that occurs in the Champagne region of France is called champagne. In contrast, the products of the same type produced in the other areas shall not be called champagne according to international practice, but generally called sparkling wine, which requires CO2 to maintain a pressure of 0.343- 0.49mpa at 20℃. 0.49mpa.
B. Sparkling wine (carbonated wine): CO2 is artificially added to wine, called sparkling wine, and CO2 is required to maintain a pressure of 98–245kpa at 20℃.
4. Classification by brewing method.
(1) Natural wine: made by fermenting grapes without adding sugar and alcohol.
(2) Fortified wine: fermented into the original wine and then added brandy or deodorized alcohol to increase the alcohol content. There are also sweet wines with added sugar.
(3) Flavored wine: Aromatic plants are soaked in grape wine and then blended to make a tonic and delicious wine infused with medicinal herbs.
(4) Grape distilled wine: The carefully blended wine is brandy, while the unblended wine is burned.
05.
Introduction of our famous wines.
1.Sunflower brand Yantai red wine: Zhang Yu Grape Winery Company, a sweet red wine, ruby red in colour, made from raw materials such as rosemary varieties with onyx red.
2.Great Wall dry wine: Great Wall Wine Co., Ltd, made of China’s specialty longan varieties, the production of pretreatment clarification process and artificial culture yeast fermentation and cold filling.
3.Dynasty brand semi-dry white wine: Tianjin Sino-French Joint Venture Wine Co., Ltd, made from muscat-type system raw materials.
4.Sunflower Brand Yantai Flavor Max: Zhang Yu Company, with 18% alcohol content and 15% sugar content, made with white wine as the base wine and precious Chinese herbs, which has delicious, tonic and fitness effects.
5.Sunflower Brand Gold Medal Brandy: Zhang Yu Company, made from entirely fermented wine, distilled and blended with brandy spices for a long time.
6.Luminous Cup Brand Chinese Red Wine: produced by Beijing Dongjiao Winery. It uses Cabernet Sauvignon and Carignan as raw materials and is made according to the enhanced wine process.
7.Red Plum Brand Tonghua Wine: produced by Jilin Tonghua Wine Company, using wild grapes from Changbai Mountain and made according to the brewing method of red wine. It represents wine made from cold-resistant mountain grapes, with 15% alcohol and 15% sugar.
8.Feng Harvest brand osmanthus aged wine: produced by Beijing Winery, made from excellent white wine with golden osmanthus as the main fragrance, and made by processing, blending, and storage.
06.
The main varieties of grapes for winemaking in China.
1. Two varieties widely used.
(1) longan: that is, autumn purple, a large number of northern cultivation, containing 16% sugar, acid 6g / L, juice rate of 72%, can be made dry white, champagne, and semi-sweet wine.
(2) Rosemary: Hamburg Muscat, native to England, the fruit contains 18-20% sugar, 5-7 g/L acid, 76% juice yield, can be made into red wine and dry white.
2, white grape varieties group: fruit colour green, yellow, white or the middle of the three excessive colour and red skin white flesh of the grape, can make different alcohol content, different sugar level of white wine. The following are typical: Carignan, White Feather, Riesling, Pinot Noir, Bianco, Izquierin, etc.
3, red grape varieties: the fruit colour from light red, purple-red to purple-black, black, can make red and white wines, common ones are Carignan, Pinot Noir, Late Red Honey, Cabernet Sauvignon, Cabernet Franc, Dragon Snake Pearl, North Alcohol, Public Wine No. 2, French Blue, Rose Dew, etc.
07.
Preparation of grape juice
I. Preparation before winemaking
Grapes are seasonal fruits with a short ripening period, transportation and preservation difficulties, so the grape pressing period is only 30-50 days a year. Many types of equipment have been idle for more than 10 months. Therefore, to ensure the production and the flavour and quality of wine, all kits and tools should be overhauled, cleaned and de-bacterized, new equipment should be prepared two months before pressing, etc.
1, Wine storage and fermentation equipment: wooden barrels, cement ponds, fermentation tanks (carbon steel tanks, stainless steel tanks)
2, Others: crushers, presses, buckets, transfer pumps, pipes, etc., filter presses, counters and various instruments.
3, Drugs: SO2, sorbic acid
Washing solution: (1) 5% sodium carbonate, (2) decolorization solution (5% sulfuric acid 10,000kg + 1kg potassium permanganate) (3) 1.5% sulfuric acid, (4) 100g/L calcium chloride, (5) lime water (10 liters of water with 0.51kg of quicklime), (6) acidic calcium sulfite (10g or 100g/l)
4, Sanitary cleaning of the whole plant
II. Harvesting and transportation of grapes
1, ripeness, unripe grapes with low sugar content, the low alcohol content of the wine made, not easy to preserve, light taste, weak body, high acidity, a raw green smell, low quality, generally can be determined according to the appearance of maturity (colour, hardness, size, seeds, etc.), sugar content, acidity, etc., while taking into account the appropriate, the type of wine produced, such as dry white with a glucose concentration of 0.16 -The concentration of glucose is 0.18-0.20kg/L for dry red wines and 0.2-0.22kg/L for sweet wines, with a general acid content of 6.5-8.5g/L. Weather conditions and time.
2. Harvesting and transportation: slightly
08.
Wine and fruit wine production necessary production equipment
A. From raw material production and processing
1.Raw material processing equipment: crusher, press, transfer pump.
2. Fermentation equipment: temperature-controlled fermentation tanks.
3, wine storage equipment: wine storage tanks, transfer pumps.
4. Filtration equipment: diatomaceous earth filter, plate and frame filter, etc.
5. Freezing Equipment: freezer, heat insulation tank or quick-freezing machine.
6. Sterilization system: boiler or other heating facilities.
7. Sterilization equipment: sterilization equipment or sterilization filtration equipment.
8. Filling equipment: semi-automatic or automatic bottle washing machine, automatic wine loading machine.
Second, the original wine processing
1.Raw material processing equipment: crusher, press, transfer pump.
2.Fermentation equipment: temperature-controlled fermentation tank.
3.Wine storage equipment: wine storage tank, transfer pump.
4.Rough filtration equipment, such as diatomaceous earth filter.
Third, processing and filling enterprises
1.Wine storage equipment: wine storage tanks, conveying pumps.
2. Filtration equipment: diatomaceous earth filter, plate and frame filter, etc.
3. Freezing equipment: freezers, insulated tanks or quick-freezing machines.
4. Sterilization system: boiler or other heating facilities.
5. Sterilization equipment: sterilization equipment or sterilization filtration equipment.
6. Filling equipment: semi-automatic or automatic bottle washing machine, automatic wine filling machine.
09.
Sorting, crushing and destemming of grapes
1. Sorting: that is, to store grapes of different varieties and quality separately to improve the average sugar content of grapes, reduce or eliminate the odour of wine, increase the fragrance of wine, and achieve the requirements of pure wine flavour, outstanding style and less or no disease. Sorting is best done when harvesting in the field, paying attention to hygiene and work requirements.
2.Crushing.
The purpose is to break the fruit to ensure the integrity of the seeds so that the juice flows out to press or fermentation; crushing methods are:
1. Hand squeezing or pounding
2. Crushing by foot
3. Double-roller crusher
4. Drum-shaped scraper crusher
Note: (1) each grain is broken, (2) the seeds can not be crushed: the seeds contain a large number of tannins and oils, (3) the fruit stalks can not be crushed: they contain substances unsuitable for winemaking and affect the quality of wine, (4) crushing equipment should not be made of iron, because it is easy to produce the disease of rupture (5) quickly remove the fruit stalks after crushing.
3. Stem removal.
Because the fruit stalk will bring a green stalk taste, making the wine astringent and bitter. At the same time can reduce the fermentation volume and improve the alcohol precision (fruit stalk contains water and no sugar but absorbs alcohol). There is a destemming crusher, crushing and destemming feeding combined machine, centrifugal crushing and destemming machine, etc.
4.Juice separation.
For the production of white wine, reduce the contact time between grape juice and air, and the pigment, tannin, and other substances in the skin hawthorn leaching less and avoid the start of fermentation quickly and the occurrence of oxidation phenomenon. It is essential to pay attention to:
1. Not to crush grapes excessively.
2. Short contact time between juice and air.
3. Less contact between juice and grape pulp.
4. Continuous operation is preferable for self-flowing juice.
The equipment includes a juice separator or a basket press to extract the juice from the self-flowing juice.
The difference between artesian juice and pressed juice: Both contain the same amount of sugar, but the squeezed juice has a higher protein content, higher tannin and pigment, so the pressed juice has a dark colour, high viscosity and poor transparency, and can only be used for low-grade wine.
5.Pressing.
In white wine, the juice is extracted from the fermented grape pulp and then pressed to make the juice fully extracted; in red wine, the fermented wine is removed from the fermented grape pulp.
Commonly used pressing equipment are:
1. Screw type hand press
2. Screw type power press
3. Basket type hydraulic press
4. Horizontal press
5. Continuous screw press, etc
6.Improvement of grape juice composition (i.e. raw material improvement)
Make the composition of grape juice to meet the process requirements and the design of wine to ensure the style and quality of wine, and the normal fermentation process, with the addition of sugar, acid adjustment, alcohol, etc.
10.
Sugar adjustment.
1. Sugar adjustment.
Brewing different varieties of wine require a fixed sugar concentration of grape juice, and other countries have relevant brewing regulations for this. For table wines, most countries do not allow the addition of sugar. Switzerland can add solid sugar but not water; the United States can not add sugar but grape juice concentrate. There are no special regulations in China. But the general flavour of the wine after adding sugar is not good, not conducive to the production of high-grade wine, the calculation of the amount of added sugar: generally, 1L grape juice contains 17g of sugar, fermentation can produce pure alcohol 1%, such as the requirement for the degree of wine is 130, to 17g of sugar to make 10 alcohol, then the amount of sugar in each litre of juice is 13X17 = 221g if the sugar content of the liquid is 17g/100ml, then each litre of juice should add sugar 221-170=51g, but in fact, since the volume of 625ml per kg of sugar dissolved in water is increased, it should be calculated according to the formula.
2. Acidity adjustment
If the acidity is too low, the bacteria will overgrow. The finished wine will have a bland taste, poor transparency and low quality. There are three methods of adjustment.
A using unripe grape juice
B with citric acid and tartaric acid adjustment: generally tartaric acid is good, 1g tartaric acid is equivalent to 0.94g citric acid, the general amount of citric acid does not exceed 0.5g / L
C appropriate to increase the amount of SO2.
If the acidity is too high, the edge can be reduced by chemical methods (adding CaCO3, KHCO3, etc.) or malic-lactic acid fermentation.
11.
Addition of SO2
(1) The role of SO2 in grape juice and wine
A fungicidal and antiseptic effect (selective fungicidal): fumigant sulphur dioxide
B antioxidant effect prevents the oxidation of aromatics, pigments and tannins, such as oxidative discoloration of white wine, oxidative rupture disease, oxidative taste caused by acetaldehyde, the occurrence and development of wine diseases.
C acidifying effect:
· Direct conversion to acid (H2SO3)
· Promoting the dissolution of organic acid salts
· Inhibiting bacterial decomposition of organic acids
D Clarifying effect: inhibits the growth and reproduction of microorganisms, delays fermentation time, and facilitates the precipitation of suspended matter.
E Dissolving effect (promote impregnation, increase the dissolution of pigments and phenolic substances.
(2) Sources of SO2 (P63-66)
A sulphur combustion – SO2 gas
B liquid SO2
C sulfite (SO2 dissolved in water)
D metabolic potassium sulfite
(3) The amount of addition, the requirements vary from country to country
SO2 is used mainly before fermentation and in storage.
A Before fermentation For red wines, before pumping into the fermenter after crushing and destemming.
For white wines, immediately after juice extraction, the concentration of SO2 should be as follows.
12.
Theory of fruit wine fermentation
I. Fruit wine fermentation microorganisms
1. Types.
(1) Yeast that plays the central fermentation role in the fermentation process – wine yeast
(2) yeast with large quantity but weak fermentation ability – pseudofilamentous yeast, round yeast, etc.
(3) film-producing yeast: aerobic yeast, producing volatile acids, aldehydes, etc., harmful, production using reduced air, strong sulphur juice, pick up the dominant yeast to control
(4) harmful bacteria and mould, make wine quality deterioration or winemaking failure
2.Characteristics of good wine yeast
(1) strong fermentation country, producing 12-160 alcohol
(2) High fermentation rate: fully ferment sugar into alcohol
(3) Can produce aroma
(4) Strong resistance to adversity
Second, the mechanism of wine fermentation
1.Alcohol fermentation mechanism
It is the metabolic product of yeast (ethanol) C6H12O6-2CH3CH2OH+2CO2
The pyruvate produced by glycolysis does not enter the tricarboxylic acid cycle. Still, it is decarboxylated into acetaldehyde, which is further reduced to ethanol, and the main chemical processes are as follows.
(1) Glucose phosphorylation: conversion of glucose and fructose to 1.6-diphosphate fructose through the action of hexose phosphorylase and hexose phosphate isomerase.
(2) Splitting of fructose 1.6-diphosphate into a three-carbon sugar, glyceraldehyde 3-phosphate.
(3) Conversion of 3-phosphoglyceraldehyde to pyruvate.
(4) Decarboxylation of pyruvate to acetaldehyde.
(5) conversion of acetaldehyde to ethanol.
Generally, when pyruvate is reached, if oxygen is available, aerobic respiration is carried out to reproduce individuals and grow and develop, and if anaerobic respiration is carried out to ferment into ethanol. Therefore, generally, in the early stage of fermentation, they supply appropriate oxygen to reproduce individuals. Then the air is reduced, and fermentation is carried out to facilitate alcohol accumulation for sucrose and maltose as fermentable sugars. Starch, cellulose, pectin for non-fermentable carbohydrates need to be hydrolyzed to use (except pectin) five-carbon sugar isomerization into six-carbon sugar to be used.
2, the generation of by-products.
Primary by-products: fermentation process accumulation of simple biochemical reactions such as acetaldehyde, pyruvate, ethyl acetate, and organic acids, etc.
Secondary by-products: after complex chemical reactions, advanced alcohols, advanced fatty acids or other sources, such as the breakdown of gums (methanol)
(1) glycerol: in the right amount to make the wine taste mellow and round, from dihydroxypyruvic acid phosphate
(2) Organic acids: lactic acid, acetic acid (the primary volatile acid), succinic acid, citric acid, etc.
(3) Advanced alcohols: Flavor substances, the second type of aroma in wine, mainly isopropyl alcohol, isoamyl alcohol, etc., formed by amino acids. (but in white wine is impurities that are the miscellaneous alcohol oil)
(4) Methanol: pectin hydrolysate, trace amount of methanol is suitable for flavour
(5) galacturonic acid and pectin decomposition products
(6) Esters: organic acids and alcohols formed
(7) aldehydes and ketones: when the right amount of flavour substances
Third, the factors affecting the yeast fermentation
1.Temperature: 25-28℃ Fermentation temperature 20-30℃, high-temperature fermentation speed, stop fermentation early; the lower the temperature, the more complete the sugar conversion, the higher the wine degree. Generally, the best fermentation temperature for white wine is 18-20℃, and the fermentation temperature for red wine is 26-30℃.
Low-temperature fermentation (20℃) has pure taste, aroma, high alcohol, high CO2, clarification, etc.
2.Acid: 3.3-3.5 when the normal fermentation (acid resistance) is conducive to fermentation safety (high acidity can inhibit the reproduction of other microorganisms).
3, pressure and CO2 affect reproduction but not death. Generally, 4-5 atmospheres of pressure can inhibit reproduction from promoting fermentation.
4, oxygen: oxygen to promote individual reproduction, anaerobic to encourage the fermentation process, generally the early aerobic, later anaerobic; production using the inverted tank to increase oxygen.
5, sugar and osmotic pressure: 14-16% of normal, 25% when the osmotic pressure has a significant impact.
6.Tannin and nitrogen
7.Alcohol 130 or more, producing high-level wine with a long fermentation cycle.
8, SO2: 10mg/L to inhibit the reproduction of harmful microorganisms, 20–30mg/L to delay the fermentation process for 6-10 hours, the general requirement of 20–120mg / L
Four, malic-lactic fermentation
Malolactic fermentation (MLF) breaks down malic acid into lactic acid and CO2 under the action of lactic acid bacteria. This fermentation causes the sourness and roughness of the new wine to disappear. The taste softens, i.e., the acidity decreases, the fruit and mellow aromas become more robust, the quality increases, and the biological stability of the wine is enhanced. This period does not allow lactic acid bacteria to break down sugar and other wine components.
13.
Wine fermentation process
White wine is clarified juice fermentation, while red wine is mixed fermentation of pomace and grape juice, i.e. fermentation and maceration take place simultaneously and dissolve tannins and pigments in solids in the wine; there is no material exchange between juice and pomace in white wine, so the juice extraction and pressing operation of white wine is carried out before fermentation.
I. Dry white wine
1.Concept
After a certain period of primary fermentation with wine yeast in the grape juice, the barrels are added or changed for post-fermentation (ageing). After ageing for several months or years, the original dry white wine can be obtained and finally blended, packaged and sterilized.
2. Pretreatment of grape juice
SO2 treatment.
When the juice temperature is 20-25℃, add SO2 to the grape juice at 50-200mg per litre, or 0.02% if the temperature is high.
After adding SO2 for static clarification, it can be done at room temperature for 24 hours, but the effect is poor. It can also be done at a low temperature of 10 – 12°C with a good product but with high energy consumption, while adding pectinase (0.1-0.15g/l) to eliminate the protective effect of pectin on the colloid and accelerate clarification. To enhance the clarification effect, 0.05-0.1% of soap clay can be added to adsorb macromolecules and impurities in the juice.
3. Adjustment of grape juice composition: omitted
4. Fermentation process
(1) Grape juice down the barrel.
Send the sulphur-treated grape juice into the fermentation barrel in about 4/5 volume and add 3-5% of the mother of wine. This process can be done by adding the mother of wine first and then sending in the juice or adding it simultaneously.
(2) Initial stage of fermentation.
The liquid surface is calm at the beginning, with the production of CO2, the fermentation temperature of 25-30℃ takes about 24 hours if the temperature is low up to 48-72-96 hours. Still, not less than 15℃, pay attention to air ventilation during this period, so the period is the stage of yeast proliferation.
(3) Fermentation vigorous period
For the alcohol fermentation stage, during this period a large amount of CO2 is released, the amount of alcohol reaches the highest, the sugar content drops to 1%, requiring control of the product temperature below 30 ℃, because it will increase the temperature 7-12 ℃, so attention should be paid to cooling; at the same time to control the floating slag, available circulation pump sprinkling spray or use the pressure plate to press the floating slag to the liquid surface.
(4) Late fermentation
After the primary fermentation is finished, the late fermentation is mainly due to the air mixed in the wine by separating and pressing to revive the yeast. The later fermentation is weaker, which is the process of fermenting the remaining residual sugar completely.
Nowadays, low-temperature fermentation at 18 – 20℃ is advocated.
For semi-dry, semi-sweet and sweet wines, the fermentation process should be artificially stopped. The methods taken are low temperature (below 10℃), high temperature (above 45℃), and the content of SO2 can be increased.
14.
Management of wine in storage and handling of stability
I. Purpose of storage.
After the end of fermentation, the wine is new, generally not delicate and unstable, to be stored for a certain period and appropriate process treatment, a series of physical, chemical, and biochemical changes will occur during the storage period, the formation of unique qualities. The storage of wine under conditions that promote quality improvement is called ageing.
1. Promoting clarification and improving the stability of wine
Unstable substances in wine, such as tartaric acid salts, tannins, proteins and colloidal substances, and small amounts of yeast and other microorganisms, are changed and then precipitated and removed.
2.Promote the maturation of wine.
New wines appear monotonous, hard, rough and thin because various changes have not reached balance and coordination. After storage, so that the different flavour substances in young wines get a harmonious balance, the wines become harmonious, smooth, delicate and mellow, and show the typical styles of various wines, i.e. the maturation of wines. Mainly oxidation, esterification and the formation of mellow aroma
II. Barrel change and barrel addition
1. Barrel changing (tank transfer).
(1) Concept: It refers to the operation of transferring a wine from one barrel to another or from one pool to another while taking various measures to ensure that the wine is separated from its sediment in the best way, which is a sedimentation process, and the sediment is the wine sludge or wine foot (sediment)
(2) The purpose of changing the barrel: First, to separate the liquor from the wine sludge, which contains yeast delicate, brittle bacterial cells and exogenous organic substances and tartar, pigment, disease destroying sediment, etc. Second, to remove excessive volatile substances and dissolve the right amount of fresh air. And make the wine uniform and consistent, as well as adjust the content of SO2.
(3) Notes.
Red wine should be more strongly aerated for the first time, reduce the amount of air for the second time, and avoid air after 1 year
b White wines should be changed under airtight conditions
c New containers should be treated, and the suction pipe should be a bent pipe with the mouth facing upwards
d It should be done in low temperature, high pressure and windless weather
e After barrel change, analysis of volatile acid and SO2 must be carried out, and SO2 should be replenished appropriately.
2.Fill the barrel.
Due to the evaporation of liquor, lowering the temperature of the product, the gas CO2 and other permeation in the wine, wine feet, etc., should be added to the barrel to reduce the fixed liquor surface in contact with the air caused by oxidation or acetic acid bacteria, it is best to use the same age, the same species, the same quality of the original wine, at least should be medium quality, the last addition of brandy on the liquor, and alcohol to prevent miscellaneous bacteria, if the following measures are not available.
Replace small containers (2) put glass balls (3) aerate with CO2 or SO2 (4) use automatic full barrel filling barrels (5) ultraviolet sterilization
15.
Purification and clarification of wine
1. Purification and clarification of lower gum.
Add a certain amount of organic or inorganic substances to the wine, which can react with the substances in the wine to produce colloidal precipitates and condense and sink the suspended substances in the wine (including V), together to the bottom of the barrel, thus making the wine clarified and transparent.
(1) Organic substances under gelation
The use of protein and tannin interaction and the principle of flocculent precipitation, commonly used organic under the gelatin materials are.
Gelatin, fish glue, egg white protein, blood powder, casein, tannin, etc.
(2) Inorganic materials under the gum.
Mainly through a high degree of dispersion and surface adsorption and mechanical filtration when sinking to achieve the purpose of clarification.
There are mainly diatomaceous and bentonite. The dosage is 400–1000mg/L
2.Decolorization: mainly for white wine.
It contains a lot of oxidized polymer of tannin and browning material. Use activated carbon, ion exchange resin, etc.
3.Wine filtration.
Such as bag filtration, filter press, diatomaceous earth filtration, etc.
4.Wine purification by centrifugal separation.
5.Cold and hot treatment of wine
Cold treatment is to accelerate the precipitation of colloidal substances in the wine, which helps clarify the wine and make the wine stable in a short period; 0.5-1℃ above the freezing point of the wine is appropriate. Heat treatment enables the wine to obtain good flavour faster, thus accelerating maturation and stability. 50-55℃, 25-20 days.
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