Wine is an ancient drink that is always popular. Prepare it from grapes, as well as from. But still, both professional winemakers and amateur winemakers prefer grape wine.

Making wine at home makes it possible to get a high-quality natural product, so many are happy to try their hand at winemaking. Good grape wine is good for the body, but it should be drunk moderately.

The process of making wine consists of several important stages and takes from 40 to 100 days.  The most important period for creating a hop drink is fermentation, which can be divided into three stages: fermentation, rapid and quiet fermentation.

During fermentation, the taste, aroma, color of the future wine, its quality, and beneficial properties are formed. Therefore, during fermentation, it is necessary to pay special attention to wine procurement and all the processes taking place in the future wine. The slightest mistake can lead to the fact that all efforts and hopes will go down the drain.

Process features

In order for the fermentation process to begin in the wine stock (pulp or juice), yeast is needed. Baking yeast will not work. For winemaking, they use natural (wild) yeast that lives on the surface of berries (there are a lot of them on grape berries), pure yeast cultures that are used in the industrial production of wine, or prepare yeast.

Temperature mode

An important role in the production of wine is played by temperature conditions. The most favorable temperatures for the fermentation of wine material (pulp, wort) are 18–20 ° C. In the room where the wort is fermenting, there should not be sharp temperature jumps, since such thermal changes negatively affect the vital activity of yeast fungi.

There should also be no draft in the room, and sunlight should not fall on the contents of the fermentation tank. If the wine material wanders in a glass container, then it must be covered with a dark cloth.

If the production of homemade wine falls in the autumn, then containers with wort should be placed in a room that can be heated. This will maintain the necessary thermal conditions, regardless of weather conditions.

Fermentation is a biochemical reaction during which heat is released. As a result of the decomposition of sugar, the temperature of the wort can significantly increase. It should be borne in mind that this can lead to negative consequences: when the temperature of the wort approaches 30 ° C, rapid evaporation of alcohol can occur, which will lead to the appearance of a bitter aftertaste.

This usually occurs during a period of rapid fermentation. Therefore, it is important to constantly monitor the temperature regime so as not to miss such a situation.
  If the temperature of the wort increases, it is necessary to cool it forcibly. To do this, if possible, temporarily reduce the temperature in the room. You can place the fermentation tank in a basin with water or cover it with a cloth dampened in cold water.

Fermentation stages

The fermentation period can be divided into several stages. Fermentation in a properly prepared wine blank begins after 6-12 hours. From the beginning of the first stage, which is called violent fermentation. It is accompanied by intense drilling, foam appears on the surface, a characteristic hiss of escaping gas is heard (wine plays).

Therefore, it is recommended to fill the fermentation bottle with wine material no more than 2/3 so that the foam cannot block the water seal. Carbon dioxide, which will not have an outlet, can not only tear the shutter, but also break the container. To avoid such a nuisance, the wine stock is mixed several times a day. The period of rapid fermentation is from 4 to 8 days.

After this, a period of quiet fermentation begins. The wort will ferment until the yeast processes all available sugar. The period of silent fermentation depends on many factors, but one of the main ones is the sugar content in the wort. A high-quality water shutter should be installed on the fermentation tank.
How long will the wine blank ferment under optimal conditions? Quiet fermentation lasts 20 days on average. During this time, the wort brightens, sediment accumulates at the bottom of the tank. The completion of this stage can be determined by stopping gas evolution (absence of bubbles). This moment should not be missed so that the wine does not stand on the lees, as this will affect its taste.

When the homemade wine is ready, it must be carefully removed from the sediment (for example, using a hose from a dropper). Filter if necessary. Taste. At this stage, you can adjust the taste of the wine. If the young wine is sour, then you can add sugar to your taste, so that it is pleasant to drink.

A hop-drink is poured into a clean container, puts a water seal to protect it from souring, and is transferred to a cool place where the wine will last 30 to 45 days. This stage is called fermentation, it completes the maturation of the drink.
  Wine is considered ripe when fermentation and sedimentation (organic and mineral) have completely ceased in it.
  To check the readiness (ripening) of the drink, fill a couple of bottles of unpainted glass, close them with twisted, left warm for 10 days. If the drink has not changed during this time, remains transparent, without sediment, then it is bottled. If there has been a change, then the wine should still be refined.

Fermentation stop

Fermentation is a rather capricious process; for its successful flow, strict adherence to all technological conditions and norms is necessary.

The slightest failure can lead to what has begun. In order to save the wine material and not lose the chance to get quality wine, the process must be resumed as soon as possible.

What can be done if fermentation has stopped?

How to stop fermentation in a finished drink

Young wine is a special product. It has a lot of bacteria and microorganisms that can suddenly start an active activity, as a result of which the fermentation process will resume. Sudden activity can be caused by temperature fluctuations or other factors. As a result, the finished wine in storage must be rescued urgently. The problem is that it is visually difficult to determine that the drink has started to ferment again.

To avoid such a nuisance, many winemakers at home stabilize a young drink with:

• pasteurization;
• alcohol fixing;
• cryostabilization.

It is fermentation that determines the quality, taste and aroma of wine. If you strictly adhere to the technology, then when the time comes to drink the finished wine of your own production, the result will not disappoint you.

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Yeast consists of elongated cells with a cross-sectional dimension of approximately 0.006 mm. In the form of microscopic cells, yeast is distributed throughout the air. Their presence is a necessary condition for the fermentation of wort. If you must pass the wort through filter paper and thereby isolate the yeast from it, then fermentation will stop and will not resume until the yeast gets into the wort in one way or another.

  The more the wort comes into contact with the air during mixing or overflowing, the more fungi it absorbs and the stronger the fermentation and development of the yeast.

Yeast is not afraid of either light or the influence of sunlight, as long as the temperature does not exceed 48 ° C. Yeast has the following chemical composition: nitrogenous substances - 62.73; fiber - 29.47; fatty substances - 2.10; minerals - 5.80.

At different temperatures, the yeast has a different degree of reproduction.

The lowest temperature at which yeast maintains its vital activity has not yet been precisely determined. But there are researchers who believe that yeast can retain the ability to stimulate fermentation even at temperatures below 0 ° C.

The highest temperature at which the yeast retains the ability to stimulate the fermentation of wort is determined differently by different researchers. Some of them believe that only by heating the wort to 70 ° C can destruction of absolutely all the fermentation nuclei be achieved. Wine requires less temperature for this.

During fermentation, a wort bucket releases about 300 g of raw yeast, which gives approximately 46% dry matter.

Yeast fungi, like all other plants, need food. It is nitrous acid and the substances that make up the ash. In particular, it is potassium and phosphoric acid. In any vegetable juice and, therefore, in grape juice, all nutrients are in greater or lesser amounts. Therefore, the wort begins to ferment when yeast enters it. The development of fungi can continue only until the substances that feed the fungi are depleted or compounds are formed that inhibit, and then completely stop the development of fungi.

Under the influence of yeast, various changes occur in the wort: the surface of the wort takes on a more or less brown color, bubbles from developing carbonic acid appear, the husk rises, forming a hat. The sweetness gradually disappears, and the wine taste develops more and more. New substances appear in the wort, such as glycerin, succinic acid, etc. The whole process is called wort fermentation. One of the main changes that occur in wort during fermentation is the conversion of sugar into alcohol and carbonic acid, with the formation of glycerin and some other substances, but in a relatively smaller amount. A certain amount of yeast can decompose only a certain amount of sugar. If there is less yeast than is necessary for the decomposition of the entire amount of sugar in the wort, or there is a lack of nutrients for their further development, then fermentation is slow at first, and then completely stops without decomposing the entire amount of sugar. As a result, the sweet taste is retained. This happens with a must containing too much sugar. The best and most favorable ratio of sugar to water is 1: 4 (1 part is sugar). Natural juice rarely lacks yeast or nutrients. But in the juice diluted with water with the addition of sugar, this part increases.

Along with yeast fungi, other fungi also develop in the must, generating mucus, mold, acetic and lactic acids, as well as various diseases. To give priority to yeast and inhibit the development of harmful microorganisms as much as possible, we recommend the following. During the general grape harvest, the best healthy and ripened clusters must be collected in a separate container. Then squeeze the juice out of them and let it ferment. In the future, this fermented wort should be placed in what was done later. The correct alcoholic fermentation is immediately triggered by the addition of a fermenting wort.

The effect of temperature on the course of fermentation of wort

At 4 ° C, fermentation almost ceases, but increases as it rises. Upon reaching 30 ° C, fermentation begins to slow down, but does not occur at 40 ° C.

Fermentation at a temperature of 25-30 ° C exposes the wine to dangerous diseases, since this temperature is favorable for the development of lactic, butyric and other acids.

In addition, it turned out that up to a temperature of 27 ° C, fermentation is constantly accelerated, and then gradually slows down.

As for the development of the bouquet, the temperature of 15–20 ° C is most favorable.

The effect of air on fermentation

Yeast fungi for their development and reproduction require exposure to air. Therefore, with poor access to air, the wort wanders incomparably slower than with a free or enhanced flow.

The effect of filtration on fermentation

Filtration greatly slows down the fermentation process. On this basis, frequent filtration can stop the fermentation process, to achieve that the wine remains sweet.

The effect of alcohol on the fermentation process

During fermentation, part of the sugar turns into alcohol. But you need to keep in mind that alcohol kills yeast. Thus, in the fermentation itself lies the reason for its termination. If by fermentation or in another way, for example, by simple addition of alcohol, it is formed in volume up to 18%, then fermentation will completely stop. The lower the temperature, the lower the percentage of alcohol that stops fermentation.

The effect of utensils on fermentation

Wort roams in a large bowl much faster than in a small one.

Wort ripening to stimulate fermentation in it

Cold wort wanders very slowly. Therefore, if the temperature of the wort is lower than 15 ° C, you should resort to artificial heating. When heating the wort, it must be borne in mind that from fermentation its temperature rises significantly. If it is required that the wort ferment (20–24 ° C), then it should be heated to a temperature of 16–18 ° C. A further increase in temperature will be achieved in the fermentation process itself.
  Wort can be heated in various ways.

First way. You can increase the temperature in the room where the wort is placed. This is the best way, but it has a negative side. If we have a little wort, then because of it we should not heat the room. It also happens that there is no specific room where you could bring the temperature to the desired level. Therefore, we offer another way to heat the wort.

Second way. It is enough to heat a separate part of the wort to such a temperature that, when mixing it with the rest, the whole mass is brought to the desired temperature. Wort can be heated directly in enameled or other utensils. This method presents some inconvenience, as the taste of boiled wort appears, which then turns into wine. As a result of this, it is not the wort itself that is heated, but the water and a vessel containing the wort is kept in it until it reaches the desired temperature.

How to slow down fermentation

It is known that fermentation at a low temperature slows down, but increases as it increases. Therefore, to slow down the fermentation, they resort to cooling the wort. This is done in the same way as warming the wort, but only with the difference that cold water is passed instead of hot water.

How to stop fermentation

Wort fermentation can be stopped by introducing sulfuric acid into it. To do this, smoke an empty barrel in the usual way, then pour about three buckets of wine into it, rinse the entire barrel with it and then smoke it again with sulfur. Then again pour 3-4 buckets and so on until the entire barrel is full.

Wort fermentation is terminated if:
  1) the wort is heated to a temperature of 40 ° C and above;
  2) the alcohol content in the wort is adjusted to 18% and higher;
  3) all yeast is removed by filtration.

Carbon monoxide (carbonic acid)

During wine fermentation, especially during rapid fermentation, carbonic acid, known as carbon monoxide, is released. This gas is extremely harmful. A person breathing in, faints, and then, if you do not provide medical assistance in time, death may occur.

To prevent such accidents, the following precautions should be taken when visiting a cellar where young wine is fermented:

1. It is advisable to visit the room together.
  2. Going into the room, you need to take a candle with you. If it burns normally, then you can go. If it goes out, this is a signal that it is dangerous to enter the room, since there is a large accumulation of carbonic acid.

Carbonic acid is 1.5 times heavier than air, therefore, it accumulates and keeps mainly below and rises up only as it accumulates. Therefore, the candle must be kept low, but not bent.

To remove the accumulated carbonic acid, it is necessary to open all doors, openings, which are only in the room. At the same time, a vessel is placed inside, into which pieces of quicklime are thrown.

If, however, carbon monoxide poisoning has occurred, then the victim must be taken out to fresh air and doused with cold water.

Sugar

Only the smallest traces of sugar remain in the prepared wine, only in liquor wines or made from dried grapes, or to which alcohol was added during fermentation, or otherwise the fermentation of the wort was delayed and contains a large amount of sugar. If in ordinary weak wines the sugar content reaches 0.1–0.2%, then sweetness is already felt. Some wines retain a small amount of sugar for a long time, so the presence of sugar in wine does not yet prove artificial addition.

Alcohol

Alcohol is one of the main parts of wine. The nature and transparency substantially depend on its content. 100 parts by weight of sugar in the wort produce 48.4 parts of alcohol in wine. Practitioners know that every percent of sugar in the wort gives 0.5% alcohol in wine. The highest alcohol content that can develop through the fermentation of wine juice is 18%. A higher content is an artificial admixture. The alcohol content in wine decreases over the years: wine loses 0.25 to 0.5% alcohol per year.

Coloring matter of colored grapes

The coloring matter of colored grapes is slightly soluble in water. It dissolves a little more in water with acid, and best of all - in a mixture of diluted alcohol with a small amount of acid. The color of wine is enhanced by overfilling, release:

a) from the husks of overripe berries;
  b) from too high a temperature;
  c) from any fine crushed powder, in particular containing protein substances;
  d) from prolonged exposure to air and light.

The amount of coloring matter depends solely on the grape variety.

Extractives make up the precipitate obtained after evaporation of the wine. They, if I may say so, are the body of wine, which determines the taste and density of the drink. The content of extractive substance is 1.4–3.0%. In sweet wines it is incomparably more.
  The mineral composition of wine has little effect on its taste.

The tannin is taken by wine during the fermentation of wort and a little when pressed from husks, grains and scallops. In pure grapes it is not there.

In contact with

Microbiological conversion of sugars (glucose and fructose) into ethyl alcohol by wine yeast. This is the main process in winemaking. All the rest are auxiliary. As the fermentation goes, we will get such wine.

In the production of dry wines - sugar must ferment completely.
In the production of semi-sweet and semi-dry - partially.

The situation is a little more complicated in the production of fortified (with the addition of alcohol) and dessert (special technology) wines. Here it is impossible to achieve high alcohol (14-17%) by natural fermentation. At 17% alcohol, the wort self-preserves and the yeast dies. Moreover, 14-17% of sugar should be present in wine. Therefore, fermentation is carried out until the desired sugar remains in the wort, and then alcohol is added, bringing its content in the wine material to the required level. That is, fermentation is interrupted by alcohol. According to the correct technology of fortified wines, natural alcohol should be at least 3% of 14%.

There is another type of fermentation that occurs in winemaking. it bacterialmalolactic fermentation . Lactic acid bacteria produce it, the same ones that cause souring of milk. They decompose malic acid into lactic and carbon dioxide, at the same time "grabbing" other organic compounds. If such a process occurs spontaneously and is not planned by the winemaker, then it can lead to damage to the wine material. There are drugs from cultured strains of lactic acid bacteria. They are used to improve the taste of highly acidic wines. But to begin such a biological acid reduction, you must first partially deoxidate the wort with chalk, then add this preparation, raise t to +20 C and stop the process by sulfitation in time. At home, this is all weakly acceptable and irrelevant.

For the processing of high-acid wort, special acid-reducing agents called acidodevoratus are best suited, which means “acid absorbers” in Latin. In the process of ordinary alcoholic fermentation, they side-convert malic acid into alcohol and carbon dioxide. Therefore, this type of fermentation is called malic ethanol . Use it to prepare dry wines from raw materials with excess acidity.

Some important information on alcohol fermentation.

At temperatures below + 10 C, fermentation stops.

At temperatures from +10 C to +27 C, the fermentation rate increases in direct proportion, that is, the warmer the faster.

From 1 gram of sugar during fermentation is formed:
- ethyl alcohol 0.6 ml. or 0.51 gr
- carbon dioxide 247 cm cubic or 0.49 gr.
- heat dissipated into the atmosphere 0.14 kcal

Sugars are actively absorbed by yeast, with a sugar content in the wort ranging from 3% to 20%.

As soon as the alcohol concentration in the wort reaches 18%, then all the wine yeast perishes. There are some types of cultured yeast that die even with a alcohol fraction of 14%. These are used for the production of wines with residual sugar.

Carbon dioxide secreted by the yeast cells in the wort slows down their work. The gas bubble, while it is small, “sticks” to the wall of the yeast cell and prevents the flow of nutrients to it. This situation continues until the cell "inflates" this same bubble to a certain size. Then the bubble pops up and drags the yeast cell with it up to the surface of the fermenting liquid. There it bursts, and the cell sinks to the bottom of the fermentation tank. This process is conventionally called "boiling", and is considered a waste of time in the process.

Types of yeast.

Fermentation can be carried out on wild yeast that live in natural conditions on a grape bush, or on cultural yeastbred and selected by humans in the laboratory.

The choice of yeast depends on the will of the winemaker.

Wild yeast and spontaneous fermentation  - live on grapes and grape bush. When processing grapes for wine, together remove the other microflora in the wort. Freshly squeezed grape juice on average contains molds in a proportion of 75 to 90%, and different types of wine yeast 10-20%. At the first stage, some microorganisms die in the wort due to the high acidity of the juice and sugar content. Some try to compete with wine yeast and begin to multiply, but they soon die too, so the reserves of dissolved oxygen in the wort run out. Wine yeast by this time reach a high concentration (about 2 million cells per cubic cm of wort), switch to anaerobic, without the participation of oxygen, type of processing of sugars. And thus, they have at their disposal the entire volume of the wort as a whole.

While it is not enough, the largest numbers are developed in the red juice of Hanseniaspora apiculata (apiculatus or spiky), in the juice of white grapes - Torulopsis bacillaris.

After accumulation of about 4% alcohol, both species die. From the “carcasses” of dead yeast, nitrogenous substances begin to flow into the must. Then it becomes possible to actively propagate the yeast of the genus Saccharomyces, mainly of the ellipsoideus species, in Russian - ellipsoid yeast. They conduct both basic fermentation and repeated fermentation. The last, which is interesting, happens, again after the appearance in the wort of nitrogenous substances from dead cells by type.

With the accumulation of 16% alcohol, ellipsoidal yeast die. The fermentation finals are carried out by alcohol-resistant oviformis yeast (egg-shaped). But they also fall out with alcohol 18%. Now the wine material is almost sterile. Only oxygen in the air can spoil it.

Fermentation with wild yeast can produce high-quality wines with a huge range of flavors and aromas. After all, several types of yeast, replacing each other, take part in their creation. But there is a significant risk of getting an unkind or low-alcoholic wine, if at some stage the relay of yeast fungi breaks.

Pure culture yeast and fermentation- Cultured yeast is obtained as the offspring of one yeast progenitor cell in the microbiological industry. Therefore, the wort is populated by only one type of yeast with absolutely the same properties. There should not be any other microorganisms in it. At the same time, you can choose exactly the yeast that will give us the product of the desired property, for example sherry yeast, champagne yeast, yeast for red wines, sulfite-resistant races, races with a high alcohol yield, heat-resistant, cold-resistant, acid-resistant and others. Competition between microflora will be eliminated, and the product will most likely turn out exactly the one on which the winemaker was counting.

Wort, before fermentation on pure crops, must be freed from wild microflora. First of all, you can wash the berries in warm water with a temperature of +35 C or hold the berries over hot steam. This mode will destroy a lot of microorganisms on the skin of berries. After draining the water, cool the raw material to + 10 C, crush and get the wort in the usual way, then spend clarification . Already fermented wort to populate with cultural yeast is useless. Wild yeast live in nature, are constantly tempered in the struggle for existence, and it will not be difficult for them to deal with cultural sissies. For the same reason, in order to give cultural yeast a head start in the struggle for the development of wort, it is better to introduce them in the form yeast wiring. They do it like this: about 0.5 liters of grape juice are taken immediately after pressing. Heated to a temperature of 80 C, poured into a sterilized glass liter jar, cooled under a sterile lid to + 25 C, and make dry yeast. Stir with a clean spoon, cover again with a lid (without corking). Further, in the wiring tank (as our jar is now called), violent fermentation should occur. The optimum temperature for it is +23 ° C. As soon as it begins to decline, it is believed that the number of yeast cells has reached a maximum peak and it is time to put them in the prepared wort.

It should be noted that after numerous experiments, the modern wine industry has come to the conclusion that pure yeast cultures can be used only to a limited extent, if the feedstock has some drawbacks or it is not possible to observe the correct temperature regime during the fermentation process.

Fermentation rate.

The best fermentation is slow fermentation. At high temperatures, yeast actively processes grape must sugars so that the bubbling bubbles of carbon dioxide formed carry aromatic, flavoring substances and even alcohol fumes into the atmosphere. The wine is flat, with unexpressed taste, and loses its degree.

Optimum temperature of the wandering wort:
- white delicate and special, champagne - 14-18 C;
- red, pink, plain white - 18-22 C;
Also, in this range, separation of tartar from the wort is better, which improves the taste of wine and the benefits of the drink.

For example, white dry wanders:
at t +10 С - 20 days,
at t +15 C - 10 days,
at t +20 C - 5 days

At temperatures from +25 to +30, excessively rapid fermentation occurs. Yeast quickly multiplies and quickly dies away, nitrogenous substances that are formed during the decomposition of dead cells constantly enter the wine material, and this increases the risk of turbidity, disease, and peroxidation.

At t above +30 C, the yeast perishes, and in the wort remains sugar (negative). In such a nutrient medium, foreign bacteria immediately begin to multiply and product spoilage occurs.

Stages of fermentation.

The entire fermentation period is conditionally divided into three phases:
fermentation, violent fermentation, quiet fermentation.

Fermentation  - the initial period when the yeast adjusts to the conditions in the fermentation tank and begin reproduction;

Violent fermentation - the period when the yeast multiplied, occupied the entire volume of the wort and switched to the anaerobic method of nutrition with the release of alcohol and other substances into the surrounding liquid, their number is growing;

Quiet fermentation  - the main sugar is converted to alcohol, the number of yeast cells is reduced.

This diagram displays stationary fermentation method. It is important that the tank is filled with fermenting wort no more than 2/3 of the volume. Otherwise, with foam in the middle phase, the contents will be thrown out. This leads to the irrational use of fermentation tanks and the instability of the processes inside it.

More stable fermentation occurs when top-up fermentation method. True, this technology can only be used to make dry wines. It is carried out as follows:
1. first, the capacity is filled by 30% of the total volume with a must and the yeast wiring in full is introduced into it; After 2 days, the fermentation will go into a turbulent stage, and the wort will warm up.

2. on the third day, another 30% of the prepared fresh wort is added;

3. after another 4 days, another 30% of fresh wort is poured into the container.

Thus, the fermentation tank is filled almost to the top, and the fermentation process itself occurs without sharp peaks and jerks in the number of yeast and products of their vital activity. And this is good for the quality of the future wine.

Fermentation of “over four” - syupercater.

Proposed by the French winemaker Semichon.
The main feature - in the wort or pulp, before the start of fermentation, alcohol is added in the amount of 5 volume percent. This amount of alcohol is enough for all unwanted microflora to die. At the same time, the saccharomycetes required for fermentation do not suffer much, but continue their work on the “cleared field”. But the addition of alcohol to the wort is prohibited by law in most wine-making countries. Winemakers "bypass" and modify the method of sypercard: first they get dry wine material with an alcohol content of about 10% by the sypercard method, then they add it to the bulk of the wort in the proportion necessary for this method.

Fermentation on the pulp.

Used in the production of red wines and some fortified white highly extractive (saturated) wines. Here, during fermentation, the task is to obtain not only alcohol, but also to remove coloring, aromatic tannins and other substances from the skin and seeds.

Pulp fermentation is always difficult. After all, it is a heterogeneous, solid and viscous mass. In addition, in order to release the necessary substances from the skin and seeds, a temperature of not lower than +28, and preferably +30 ° C, is necessary. But at +36 ° C, yeast lose activity, at +39 ° C they die.
That is, a narrow temperature range remains for fermentation on the pulp
from +28 to +32 C.

Fermentation on a pulp with a floating hat.It is carried out in tanks or open tanks . Wort sulfite at the rate of 100 mg / 1 kg. They fill the container 4/5 of the volume, make yeast wiring. Stir.

After some time, rapid fermentation begins. The emitted carbon dioxide carries all particles to the surface (pulp flakes, skin, pieces of ridges and stalks) and keeps them afloat there. The pulp is stratified into a liquid and a “cap” of a solid fraction, floating on the surface, and most often protruding above it. The upper side of the "cap" for several hours is populated by acetic bacteria, Drosophila flies and oxidized by air. That is, the initial stage of wine spoilage occurs - acetic acid souring. To prevent this phenomenon and improve the extraction of dyes, it is necessary to mix the contents of the container 5-8 times a day for 5 days.
As soon as the wort acquires a saturated color, it is drained, the pulp is pressed and the two liquids are combined and held until the end of fermentation. In this way, the most beautifully colored and rich in taste wines are obtained.

Submerged fermentation on pulp  - in order to reduce the number of stirings in the "floating cap" method, they came up with a simplified "immersed hat" method. The "hat" is recessed to a depth of about 30 cm using a grill. The amount of stirring with the head immersed may be less, but the color of the wine will be worse accordingly.

Both types pulp fermentation can also be carried out in closed containers. In this case, a layer of carbon dioxide is formed over the cap, which to some extent resists acetic acid souring and simplifies the process.