Homemade wine is made according to different recipes, from different ingredients and often with the addition of others, such as cognac, liqueur, white and red wines for blending. The ripening period of the drink largely depends on the composition and recipe.

The most famous homeland of home-made wine is France; for many centuries the French have been making wine using their unique technologies.

Recipe features

There are various time frames for how long a wine must stand to ferment. For example, if you want to get young wine, not very sparkling, then 10-15 days will be enough, provided that you see that almost all gas bubbles have come out of the bottle.

Ingredients for homemade wine

The infusion period of the wine depends directly on its filling. For example, wine made from rowan berries is aged for a whole year, from gooseberries - for half a year, and the "fastest" variants of wine material are currants and cherries. You can taste wines made from these berries in 2 months.

Signs of wine readiness

One of the signs that a wine is ready is its color. The wine should clarify, and all the cloudy sediment should remain at the bottom. The drink will have to be carefully poured into another container at least twice during the entire fermentation period so that the sediment remains in the old bottle. Experienced winemakers recommend draining the wine regularly - once a month or two. The more often you pour the drink into a new bottle, leaving the sediment in the old container, the better your wine will turn out, it will have an amazing light shade.

It is also important not to forget that during the period when the wine is infused, it must be placed in a dark room, preferably one where it is cool.

Do not forget that the longer the wine is infused, the stronger and more tart taste it will have.

Many people use a rubber glove instead of a cork on the bottle, it is believed that if the glove no longer swells, the wine is ready, and all the bubbles have already come out. You can also make a hole in the cork and stick a regular drinking tube in there, through which all gases will escape during fermentation.

If you follow these fairly simple rules, you can definitely understand whether your wine is ready.

In the history of home winemaking, there are examples when a winemaker put a container in a more or less suitable place, then safely forgot about it, and after 2-3 months he received a tolerable drink. However, this is either experience or luck. In most cases, it is necessary to intervene in the fermentation process and control its quality.

For any homemade wine, there are two, sometimes three stages (the last two do not have clear boundaries) of fermentation:

• the initial stage - it is at this stage that the fungi "sit quietly", getting used to the new environment and often causing anxiety in a novice winemaker;
• active - the yeast multiplies rapidly, the beginning of this period is marked by the active production of carbon dioxide, the mass hisses, bubbles, a precipitate forms;
• quiet - fermentation continues, but in deeper layers. There are few bubbles.

The second stage can be of different duration, it depends on what strength of the future drink is desirable. Vigorous fermentation can be delayed a lot to end up with a stronger homemade wine. Bubbles are very actively visible for the first 2-3 days.

The next phase - quiet fermentation - lasts as long as the fungi have enough nutrition, they will multiply until they have absorbed all the sugar, decomposing it into alcohol and carbon dioxide. In the recipe, the fermentation process is as follows

• Prepared raw materials for wine (wort, pulp) are poured into a container, covered with gauze, placed in a warm, dark place;
• As soon as the first gas bubbles appear (fermentation has entered an active phase), a water seal is put on the container (most often, it is covered with a glove). This stage has a different duration, for example, the fermentation of homemade wine from apple juice and mountain ash (temperature 18-28 ° C) will take 25-40 days. The end of the stage is determined by dropping the glove. Young wine is ready;
• Maturation. This is a calm period. You can add sugar to wine. Or alcohol, which will stop the fermentation process. The timing is also different. For the same apple-mountain ash wine, it is 2-3 months in a darkened room at a cooler temperature of 10-16 ° C.

Interesting: winemakers have different opinions about the youthfulness of wine. Some believe that it is young only a few days after the end of the stage of violent fermentation, some give it a few months of youth before the beginning of a new stage of life - the maturation phase.

Timing

There is no definite answer to the question of how long homemade wine should ferment. The process can take from 1 to 3 months, depending on the temperature, the amount of sugar in the wort and the quality of the yeast.

Let's take a look at the general points a budding winemaker should know about these three whales of successful fermentation. Knowing them, you can independently find answers to the questions of what to do and how to make the wine play a second time if it does not ferment.

Whale one: temperature regime

The optimum fermentation temperature for wine is considered to be 15–25 °, for white wines the best temperature is 14–18 ° С, for red wines - 18–22 ° С. At what specific temperature the wine should ferment - it is up to the winemaker, focusing on the behavior of the wort and adhering to the ranges set by the recipe.

When choosing a temperature, it is important to take into account other factors. The wort is rich in sugar, cold, small bottles, therefore, the temperature should be high - 20 ° C. Wort is sour, warm (above 12 ° C), slightly sweetened - 15 ° C is enough.

At a low temperature of 9–10 ° C, fermentation is also possible, but it will take longer.

A high temperature (over 25 ° C) can only be beneficial at the beginning. For a mixture that already contains a certain amount of alcohol, this temperature is harmful.

It is difficult to regulate the temperature in home-made. But there are examples where wine was successfully made from not very sweet raspberry jam, first standing at room temperature and then exposed on a cool winter balcony.

Kit two: yeast

How correct and fast the fermentation process will be depends on their quantity and activity. In turn, the amount of yeast is determined by many factors: the already mentioned temperature, the duration of air access to the wort and, finally, the quality of the wort.

When it comes to grapes, winemakers know that the fermentation of must from grapes grown on fertile, rich soils will be more vigorous and at the same time even. On average, the richer and more “nutritious” the composition of the feedstock, the more active and fast the fermentation process will be.

Yeast quality also varies. CWD (pure cultures of wine yeast) behave more actively and evenly, wild yeast is more unpredictable.

During fermentation, yeast cells settle to the bottom, blocking air access by those at the very bottom - inert zones are formed that slow down the process. Stirring them periodically with a spatula will help speed up the process, so as to destroy the layers. To destroy them, it is also enough to throw a few fresh berries. Sometimes, to speed up fermentation, it is recommended to ventilate the wort, providing the fungi with oxygen at the initial stage.

Keith three: sugar level

Wine from a sweet "source", for example wine made from jam, does not need additional sweetening. Only natural sugars found in fruits and berries can be used. In ready-made recipes, it is difficult to specify exactly all the parameters on which the sweetness of berries and fruits for wine depends: the degree of their ripeness, variety, harvest time, time from harvest to the moment of use. Therefore, the expected sweetness of the wort does not always correspond to the real one, and yeast fungi, which need sugars for reproduction, may simply not have enough nutrition.

These are general points to be understood before using any recipe. What to do if either berry wine does not ferment or has stopped fermenting - you need to look for the answer to this question yourself, including your own instinct. It is not for nothing that many winemakers call the making of wine a creative affair, and even claim that they enjoy the process more than the result.

All possible difficult points and ways to solve them are discussed below. But this does not mean that the reason that your wine does not ferment is one, there may be several.

The process has not started yet

Do not think that the installation of a water seal automatically means the beginning of fermentation. The wine will begin to ferment after a few days. Three days before the start of the process is normal. The term depends not only on the type of yeast, but also on the amount of sugar, temperature and raw materials.
For example, wine made from jam, popular at home, often tests the patience of novice winemakers. To start processing sugar, yeast needs to settle into a new environment.
If bubbles, indicating the onset of fermentation, did not appear after 72 hours, then there really were problems in the wine preparation procedure. Sometimes, if the room is cool, it makes sense to wait even longer - 5 days.

Wine does not ferment: reasons

Here we will consider all the possible reasons why wine does not ferment, we will give ways to solve each problem. Here you can also find answers to the question of why the wine stopped playing ahead of time and what to do to stimulate the process.

Temperature

The room is not warm enough (less than 18–25 ºC), perhaps the container is in a draft. In the passage rooms, there are often low-lying drafts that are invisible to humans. At temperatures below +16 ºC, yeast fungi "fall asleep", in heat (above 25 ºC) they die. Is it possible to save wine that has stood at the wrong temperature and has not started to play? Yes. Move the jar to a suitable place, add live yeast or sourdough.

Particular attention is paid to low temperatures, they can greatly slow down the process. Wine under a glove can ferment in warmth for only a few weeks, in coolness - up to several months. If you have come to the conclusion that the thing is exactly cool, can you move the bottles of wine to a warmer place to speed up its readiness? Yes. Just make sure that the temperature in the new room is not too high.
There is a nuance when using a pure yeast culture. Such yeast is not added to the main container, but a sourdough is prepared for their faster activation: 1 tbsp. l. sugar, in this yeast nutrient medium, wait 40 minutes. The ready-made sourdough is added to the main wort. It is necessary to ensure that the temperature of the starter and wort in the main container is close. Even a slight difference of 5–7 ° C is traumatic for fungi, and they die.

Sugar

There is little sugar in the wort. In this case, the yeast fungi simply have nothing to feed on, they do not multiply, alcohol is not formed, the process does not go. Sugar should be between 10 and 20% of the wort volume. To check if the sugar content is sufficient, it is best to purchase a special device - a hydrometer (or sugar meter). It is inexpensive - about 300-400 rubles. However, if it is not there, it remains to use only a very inconvenient subjective method - the taste. If the house wine does not ferment for this reason, sugar must be added.
After adding sugar, the liquid is thoroughly mixed until dissolved. Even better: drain 1 liter of wort, dissolve the required amount of sugar in it, pour the resulting syrup back into the main wort.

It will be optimal to initially calculate the amount of sugar per kg of raw material as accurately as possible, and not blindly trust the recipe. There are special formulas.

If the wine stops fermenting after sweetening, then perhaps there is too much sugar, in which case it works as a preservative. Dilute the wort with warm filtered water.

It is advisable to adhere to the rule of gradually adding sugar. The total amount calculated based on the type of raw material and the degree of sweetness of the finished drink (sweet, semi-sweet, dry) is divided into four doses. 2/3 - before fermentation. Divide 1/3 into three equal parts and add to the wort after 4 days, after a week and after 10 days from the beginning of fermentation.

What to do with homemade fermented wine? Usually, by fermentation of a finished product, they mean a completely different fermentation - a bite one. Acetic acid bacteria break down wine alcohol into water and cut acid. For 3-5 days, the wine acquires an unpleasant sour taste. A sour drink can no longer be saved. This trouble can only be prevented. In industrial production, sulfidization (sulfur treatment) is used.

Yeast

Little yeast. This problem often arises when trying to make wine on "wild" yeast, that is, those that were on the surface of the berries. Initially, they could not have been enough, or they died (for example, in the heat). If the wine ferments poorly for this reason, then it is enough to buy wine yeast in specialized stores. It is also possible to add dark unwashed raisins. Sourdough preparation is possible, but it will take a lot of time. Or you should put the starter culture in advance: 200 g of raisins, 50 g of sugar are poured with 2 glasses of warm water, covered with a gauze plug, kept in a warm dark place for 3-4 days. The finished starter culture can be stored in the refrigerator for up to 10 days.

A nuance for those who work with pure cultures of wine yeast. Before adding them, the wort is often sterilized with sulfites. And this is where patience is needed: you cannot add yeast immediately after processing, you need to wait a day for the sulfur to evaporate from the liquid. The container with the wort on this day is covered only with gauze.

Oxygen and tightness

Low oxygen. Quite a common mistake of beginners. The fermentation process consists of two periods: the first is short and the second is long. At the first stage, the access of air (oxygen) is important, tightness is needed at the second stage. If there is too little oxygen during primary fermentation, the yeast becomes nutritionally deficient and stops multiplying. That is, at first it is not needed, it is enough to cover the neck of the container with gauze folded in several layers. If the odor trap is already in place, simply remove it and replace it with gauze.

Lots of oxygen. This problem occurs during the second stage of fermentation. Here, on the contrary, tightness is important and only a small access for the release of carbon dioxide. If the size of the holes is too large, too much oxygen will flow to the wort, and this leads to the oxidation of the product - it will no longer be possible to save the sour drink. It is best to use a medical glove that is worn over the neck of the vessel as a water seal. To release carbon dioxide, it is enough to make a small puncture on one finger with a thin needle. This odor trap is easy to control. The glove is deflated, which means that the fermentation process has stopped. Either the puncture is too large and the glove needs to be replaced, or the joints should be checked, perhaps carbon dioxide is escaping in other ways.

A convenient way to control air access are single plastic or glass blockers with two flasks and a hose. Sulfite solution is poured into each flask of the blocker a little less than half, the end of the hose is dipped into the wine. Carbon dioxide sequentially passes through the hose through the first flask (or chamber), then through the second. If the gas pressure has decreased and a vacuum has formed, the sulfide solution moves into the first chamber, an urgent need to add wine to the container.

Raw materials

What to do with fermented jam? This is how winemakers are often born: a suitable source accidentally turned up, and now a beginner conjures with gloves and studies the technology of making alcoholic beverages. And then he wonders why the wine from the jam does not ferment at a normal pace, it ferments for a long time, or the process has stopped. Possible error in this case: the raw material may be too thick. In a jelly-like environment, it is difficult for fungi to multiply. Those who make wine from pulp, that is, from the skins and seeds, may face the same problem.

Solution: If the wine does not ferment for this reason, clean filtered warm water should be added. If the pulp was pressed (juice was used for primary wine), then the amount of water should correspond to the amount of juice removed. Be sure to pay attention to whether there is enough yeast for the new amount.

Mold

This is a common occurrence in those who use wild yeast. The surface of the wort is covered with a film, a smell appears, the wine does not play. Mold is also mushrooms, but not the ones that are needed. They begin to multiply as a result of pathogens getting into the wort (there were rot particles on the berries), and favorable conditions for them (high temperature, 22–28 ºC, high humidity, above 85%, little alcohol, low acidity of the starting material). Alas, in case of severe infection, it is better to throw out the wort. Not only will the finished product in this case have an unpleasant taste, it can be poisoned with such wine.

If the solution is not yet highly contaminated, it can still be made to ferment. Remove all moldy areas and then pour the concentrate into a fresh container. Make sure that the top layer does not get into the new dishes, therefore it is better to pour through a rubber tube. The wort is boiled at 70–75 ° C for several minutes, left to cool at room temperature, and then stabilized by adding fresh juice and sugar. If there is a lot of mold, removing the visible parts of it will do nothing, the drink is already contaminated.

To prevent the appearance of mold, use preventive methods: carefully sterilize all elements in contact with the material, wash your hands, carefully select the raw materials - remove berries even with barely noticeable dark spots. The berries are not washed, but it is not difficult to achieve the cleanliness of all objects in contact with them.

It is very risky, from the point of view of mold, to make wine from the pulp. When floating up, the pulp comes into contact with oxygen, which can lead to the development of unwanted fungi. Stir the wort so that the mash sinks back. It has already been said above that the wort should not be too thick. But it should not be too liquid either, this provokes the frequent emergence of "solid particles". Too low acidity also contributes to the appearance of mold, you can add a little citric acid. And, of course, carefully monitor the level of oxygen access to the future drink.

The process began and then stopped abruptly

The situation when the wine has stopped fermenting can also occur. The process has started successfully, the wort is in the second stage of fermentation, and then the process suddenly stops. There are two reasons for this. First, homemade wine does not ferment, because the liquid is contaminated with microorganisms that inhibit the growth of yeast fungi. In addition to mold, there are many other "creatures": viruses, bacteria that cause diseases, which are dangerous for homemade wine. In this case, there is little chance of saving the product.
The second reason why wine does not ferment is that there is already too much alcohol in the liquid. Fungi die if the alcohol is more than 14%. If this is the case, the wine will begin to ferment after adding warm water, yeast and checking the temperature. If the balance is reached, the process should continue.

Completion

If no hiss is heard, no bubbles are visible, the glove has fallen, then the fermentation procedure may have already been successfully completed, and the wine is ready. The timing of readiness is as follows:

• Wild yeast - 20-30 days. Under ideal conditions (warm, abundant nutrients) - 2 weeks.
• Pure yeast cultures are able to process all the sugars from the wort - in 5 days or a week.

If the berry wine stops fermenting after a week, what to do? Taste it, perhaps the fermentation process was so successful that it has already been completed. The finished drink will not be sweet, it has a bitter-sour harmonious taste without pronounced sweetness. You can use a hydrometer. The specific gravity of the wine ready for the next stage is 998–1010 g / dm3. Such a drink is clarified and sent for quiet fermentation in cooler conditions.

If the wine at home stopped fermenting after a week, but still remains syrupy, sweet, then the process stopped early. Analyze the possible causes from the list above and take steps to stimulate fermentation. Drinking unfermented wine is not recommended.

Let's sum up

A simple answer to the question of why wine does not ferment and what to do in general is impossible. It all depends on the stage at which the stop occurred and the specific conditions (temperature, recipe, type of yeast). To find the exact cause, analyze any parameters that may have influenced the behavior of the yeast. In general, the flair of a winemaker is not so much an innate talent as experience.

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

In the production of dry wines, the sugar must be completely fermented.
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. It is impossible to achieve high alcohol content (14-17%) here by natural fermentation. At 17% alcohol, the wort self-preserves and the yeast dies. Moreover, the wine should contain 14-17% sugar. 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 alcoholization. According to the correct technology of fortified wines, natural alcohol should be at least 3% out of 14%.

There is another type of fermentation that occurs in winemaking. it bacterialmalolactic fermentation ... It is produced by lactic acid bacteria, the same ones that cause sour milk. They decompose malic acid into lactic acid 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 spoilage of the wine material. There are preparations from cultured strains of lactic acid bacteria. They are used to improve the taste of highly acidic wines. But to start such biological acid reduction, you first need to partially deoxidize the wort with chalk, then add this preparation, raise t to +20 C and stop the process with sulfitation in time. At home, this is all poorly acceptable and irrelevant.

For the processing of highly acidic wort, a special acid-reducing yeast named acidodevoratus is better suited, which means "acid absorbers" in Latin. In the process of normal alcoholic fermentation, they side-convert malic acid into alcohol and carbon dioxide. Therefore, this type of fermentation is called apple ethanol ... It is used to prepare dry wines from raw materials with excess acidity.

Some important information about alcoholic 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 it forms:
- ethyl alcohol 0.6 ml. or 0.51 gr
- carbon dioxide 247 cm3 cubic or 0.49 gr.
- heat dissipated into the atmosphere 0.14 kcal

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

As soon as the alcohol concentration in the wort reaches 18%, all wine yeast is killed. There are some types of cultured yeast, which die even when the alcohol content is 14% or more. These are used to make wines with residual sugar.

Carbon dioxide released by 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 supply of nutrients to it. This situation continues until the cell "inflates" this very bubble to a certain size. The bubble then floats up and drags the yeast cell up with it to the surface of the fermenting liquid. There it bursts, and the cage sinks to the bottom of the fermentation tank. This process is conventionally called "boiling" and is considered a waste of time in the process.

Yeast types.

Fermentation can be carried out on wild yeast, which live naturally on a grape bush, or on cultural yeast, bred and selected by humans in laboratory conditions.

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, remove other microflora into the must. Freshly squeezed grape juice contains, on average, molds in a proportion of 75 to 90%, and different types of wine yeast 10-20%. Some of the microorganisms die in the wort already at the first stage due to the high acidity of the juice and sugar content. Some try to compete with wine yeast and begin to multiply, but soon they die too, as the reserves of dissolved oxygen in the wort run out. Wine yeast by this time reaches a high concentration (about 2 million cells per cubic cm of wort), switches to anaerobic, without the participation of oxygen, type of sugar processing. And, thus, they get at their disposal the entire volume of the wort entirely.

While it is not enough, the greatest numbers develop in the red juice of Hanseniaspora apiculata (apiculata or pointed), in the juice from white grapes - Torulopsis bacillaris.

After the accumulation of about 4% alcohol, both species die off. From the "carcasses" of dead yeast, nitrogenous substances begin to enter the wort. After that, it becomes possible to actively reproduce the yeast of the genus Saccharomyces, mainly of the ellipsoideus species, in Russian - ellipsoid yeast. They carry out both the main fermentation and the second fermentation. The last thing, which is interesting, happens, again after the appearance of nitrogenous substances in the wort from the dead cells of fellow-species.

With the accumulation of 16% alcohol, ellipsode yeast dies. The final fermentation is carried out by the alcohol-resistant yeast oviformis (ovoid). But they also fall out with an alcohol of 18%. Now the wine material is practically sterile. Only air oxygen can spoil it.

Fermentation with wild yeast can produce high quality wines with a wide range of flavors and aromas. Indeed, several types of yeast are involved in their creation, replacing each other. But there is a significant risk of getting unkind or low-alcoholic wine if at some stage the yeast relay is interrupted.

Cultured yeast and fermentation on pure cultures- cultural yeast is obtained as the offspring of one progenitor yeast cell in the conditions of the microbiological industry. Therefore, the wort is inhabited by only one type of yeast with exactly the same properties. There should not be any other microorganisms in it. At the same time, you can choose exactly those 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-tolerant, etc. Competition between microflora will be excluded, and the product will most likely turn out exactly the one that the winemaker was counting on.

Wort, before fermentation on pure cultures, 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 the mass of microorganisms on the skin of the berries. After the water has drained off, cool the raw material to +10 C, crush and get the wort in the usual way, then spend clarification . Already fermented wort is useless to populate with cultural yeast. Wild yeast lives in natural nature, is 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: take about 0.5 liters of grape juice immediately after pressing. It is heated to a temperature of 80 C, poured into a sterilized glass liter jar, cooled under a sterile lid to + 25 C, and dry yeast is added. Stir with a clean spoon, cover again (without capping). Further, in the distribution tank (as our bank is now called), vigorous fermentation should take place. The optimum temperature for it is +23 C. As soon as it begins to decline, it is considered that the number of yeast cells has reached the maximum peak and it is time to place them in the wort prepared for this.

It should be noted that after numerous experiments, the modern wine industry has come to the conclusion that the use of pure yeast cultures can be limited, if the raw material has any drawbacks or it is not possible to maintain the correct temperature regime during the fermentation process.

Fermentation rate.

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

Optimum temperature for fermenting wort:
- delicate and special whites, champagne - 14-18 С;
- red, pink, simple white - 18-22 С;
Also, in this range, the separation of tartar from the must is better, which improves the taste of the wine and the benefits of the drink.

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

At temperatures from +25 to +30, excessively vigorous fermentation occurs. Yeast multiplies rapidly and dies off quickly, nitrogenous substances constantly enter the wine material, which are formed during the decomposition of dead cells, and this increases the risk of turbidity, disease, and over-oxidation.

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

Fermentation stages.

The entire fermentation period is conventionally divided into three phases:
fermentation, vigorous fermentation, quiet fermentation.

Fermentation- the initial period when the yeast adapts to the conditions in the fermentation tank and begins to multiply;

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

Quiet fermentation- the main sugar is processed into alcohol, the number of yeast cells decreases.

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

Fermentation is more stable when top-up fermentation... True, this technology can only be used for the production of dry wines. It is carried out like this:
1. first, the container is filled to 30% of the total volume with wort and yeast wort is introduced into it in full; After 2 days, fermentation will turn into a stormy stage, and the wort will be warmed up.

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

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 their waste products. And this is good for the quality of the future wine.

Fermentation "over four" - supercatre.

Proposed by the French winemaker Semichon.
The main feature is that alcohol is added to the wort or pulp, before the start of fermentation, in an amount of 5 percent by volume. This amount of alcohol is enough for all unwanted microflora in the wort to die. The saccharomyces yeast necessary for fermentation does not suffer at all, but continues its work on the "cleared field". But the addition of alcohol to the wort is prohibited by the laws of most wine-making countries. Winemakers “bypass” and modify the supercart method: first, they obtain dry wine material with an alcohol content of about 10% using the supercard method, then add it to the bulk of the wort in the proportion required for this method.

Fermentation on the pulp.

It is used in the production of red wines and some fortified white highly extractive (rich) 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.

Fermentation of the pulp 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 is required not lower than +28, and preferably +30 C. But at +36 C the yeast loses its activity, at +39 C it perishes.
That is, a narrow temperature range remains for fermentation on the pulp
from +28 to +32 C.

Fermentation on the pulp with a floating hat. Conducted in vats or open containers . The wort is sulfite at the rate of 100 mg / 1 kg. They fill a container with it by 4/5 of the volume, add yeast wiring. Stir.

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

Fermentation on a pulp with a submerged hat- to reduce the amount of stirring in the "floating cap" method, a simplified "submerged cap" method was invented. The "hat" is sunk to a depth of about 30 cm using a grate. The number of stirring times with the cap immersed may be less, but the color of the wine will be correspondingly worse.

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

Alcoholic fermentation is the basis for the preparation of any alcoholic beverage. This is the easiest and most affordable way to get ethyl alcohol. The second method, ethylene hydration, is synthetic, rarely used and only in the production of vodka. We will look at the characteristics and conditions of fermentation in order to better understand how sugar is converted into alcohol. From a practical point of view, this knowledge will help to create an optimal environment for yeast - to correctly place the mash, wine or beer.

Alcoholic fermentation Is the process of converting glucose by yeast into ethyl alcohol and carbon dioxide in an anaerobic (oxygen-free) environment. The equation is as follows:

C6H12O6 → 2C2H5OH + 2CO2.

As a result, one molecule of glucose is converted into 2 molecules of ethyl alcohol and 2 molecules of carbon dioxide. In this case, energy is released, which leads to a slight increase in the temperature of the environment. Also during fermentation fusel oils are formed: butyl, amyl, isoamyl, isobutyl and other alcohols, which are by-products of amino acid metabolism. In many ways, fusel oils form the aroma and taste of the drink, but most of them are harmful to the human body, so manufacturers are trying to cleanse alcohol from harmful fusel oils, but leave useful ones.

Yeast- These are unicellular spherical mushrooms (about 1500 species), actively developing in a liquid or semi-liquid medium rich in sugars: on the surface of fruits and leaves, in the nectar of flowers, dead phytomass and even soil.

This is one of the very first organisms "tamed" by man, mainly yeast is used for baking bread and making alcoholic beverages. Archaeologists have found that the ancient Egyptians 6000 years BC. NS. learned how to make beer, and by 1200 BC. NS. mastered the baking of yeast bread.

Scientific research into the nature of fermentation began in the 19th century, the first chemical formula was proposed by J. Gay-Lussac and A. Lavoisier, but the essence of the process remained unclear, two theories arose. The German scientist Justus von Liebig assumed that fermentation is of a mechanical nature - the vibrations of the molecules of living organisms are transferred to sugar, which is split into alcohol and carbon dioxide. In turn, Louis Pasteur believed that the basis of the fermentation process is biological nature - when certain conditions are reached, yeast begins to convert sugar into alcohol. Pasteur was able to experimentally prove his hypothesis, later the biological nature of fermentation was confirmed by other scientists.

The Russian word "yeast" comes from the Old Slavonic verb "drozgati", which means "to crush" or "knead", there is a clear connection with the baking of bread. In turn, the English name for yeast "yeast" comes from the Old English words "gist" and "gyst", which mean "foam", "gas" and "boil", which is closer to distilling.

Sugar, sugar-containing products (mainly fruits and berries), as well as starch-containing raw materials: grain and potatoes are used as raw materials for alcohol. The problem is that yeast cannot ferment starch, so you first need to break it down to simple sugars, this is done by an enzyme - amylase. Amylase is found in malt, a germinated grain, and is activated at high temperatures (typically 60-72 ° C), and the process of converting starch to simple sugars is called saccharification. Malt saccharification (“hot”) can be replaced by the addition of synthetic enzymes, which does not require heating the wort, which is why the method is called “cold” saccharification.

Fermentation conditions

The following factors affect the development of yeast and the course of fermentation: sugar concentration, temperature and light, acidity of the environment and the presence of trace elements, alcohol content, oxygen access.

1. Concentration of sugar. For most yeast races, the optimal sugar content of the wort is 10-15%. At a concentration above 20%, fermentation weakens, and at 30-35% it is almost guaranteed to stop, since sugar becomes a preservative that prevents the yeast from working.

Interestingly, when the sugar content of the medium is below 10%, fermentation also proceeds weakly, but before sweetening the wort, you need to remember about the maximum concentration of alcohol (4th point) obtained during fermentation.

2. Temperature and light. For most yeast strains, the optimum fermentation temperature is 20-26 ° C (bottom-fermented brewer's yeast requires 5-10 ° C). The allowed range is 18-30 ° C. At lower temperatures, fermentation slows down significantly, and at values ​​below zero, the process stops and the yeast "falls asleep" - falls into suspended animation. To resume fermentation, it is enough to raise the temperature.

Too high a temperature destroys the yeast. The endurance threshold depends on the strain. In general, values ​​above 30-32 ° C are considered dangerous (especially for wine and beer), however, there are separate races of alcoholic yeast that can withstand wort temperatures up to 60 ° C. If the yeast is "boiled", you will have to add a new batch to the wort to resume fermentation.

The fermentation process itself causes a temperature rise of several degrees - the larger the volume of the wort and the more active the yeast, the stronger the heating. In practice, temperature correction is done if the volume is more than 20 liters - it is enough to keep the temperature below 3-4 degrees from the upper limit.

The container is left in a dark place or covered with a thick cloth. The absence of direct sunlight allows you to avoid overheating and has a positive effect on the yeast's work - fungi do not like sunlight.

3. Acidity of the environment and the presence of trace elements. The medium with an acidity of 4.0-4.5 pH promotes alcoholic fermentation and inhibits the development of third-party microorganisms. In an alkaline environment, glycerin and acetic acid are released. In neutral wort, fermentation proceeds normally, but pathogenic bacteria are actively developing. The acidity of the wort is adjusted before adding the yeast. Often, amateur distillers increase the acidity with citric acid or any acidic juice, and to reduce the must, they quench the wort with chalk or dilute with water.

In addition to sugar and water, yeast requires other substances - primarily nitrogen, phosphorus and vitamins. These microelements are used by yeast for the synthesis of amino acids that make up their protein, as well as for reproduction at the initial stage of fermentation. The problem is that it will not be possible to accurately determine the concentration of substances at home, and exceeding the permissible values ​​can negatively affect the taste of the drink (especially for wine). Therefore, it is assumed that starchy and fruit raw materials initially contain the required amount of vitamins, nitrogen and phosphorus. Usually, only pure sugar mash is fed.

4. Alcohol content. On the one hand, ethyl alcohol is a waste product of yeast, on the other hand, it is a strong toxin for yeast fungi. At a concentration of alcohol in the wort of 3-4%, fermentation slows down, ethanol begins to inhibit the development of yeast, at 7-8% yeast no longer multiplies, and at 10-14% it stops processing sugar - fermentation stops. Only some strains of cultured yeast bred in laboratory conditions are tolerant to alcohol concentrations above 14% (some continue to ferment even at 18% and above). About 0.6% alcohol is obtained from 1% sugar in the wort. This means that to obtain 12% alcohol, a solution with a sugar content of 20% is required (20 × 0.6 = 12).

5. Oxygen access. In an anaerobic environment (without oxygen), yeast is aimed at survival, not reproduction. It is in this state that the maximum alcohol is released, therefore, in most cases, it is necessary to protect the wort from air access and at the same time organize the removal of carbon dioxide from the container in order to avoid increased pressure. This task is solved by installing a water seal.

With constant contact of the wort with air, there is a danger of souring. At the very beginning, when fermentation is active, the emitted carbon dioxide pushes the air away from the surface of the wort. But at the end, when fermentation weakens and less and less carbon dioxide appears, the air enters an open container with wort. Under the influence of oxygen, acetic acid bacteria are activated, which begin to process ethyl alcohol into acetic acid and water, which leads to spoilage of wine, a decrease in the yield of moonshine and the appearance of a sour taste in drinks. Therefore, it is so important to close the container with a water seal.

However, oxygen is required for yeast to multiply (to achieve optimal amounts). The usual concentration that is in the water is sufficient, but for accelerated multiplication of the mash, after adding the yeast, leave it open for several hours (with air access) and mix several times.

Quiet fermentation and care

The poured wine is not yet completely transparent. It also contains part of the yeast and trace amounts of sugar, which did not decompose during vigorous fermentation. In addition, from contact with air during pouring, the protein substances dissolved in it begin to fall out of the wine, which should be removed from the wine, otherwise it may subsequently become permanently turbid and become fragile. All this happens during quiet fermentation, also called after-fermentation of wine. Fermentation usually ends in 7-10 weeks. In some cases, it lasts 3-4 months and usually ends by the spring of the year following the preparation of the wine.

Its ending is determined by taste. Fermented wine begins to lighten, a sediment forms at the bottom of the bottle. 8-10 days after the end of fermentation, the clarified part is poured into a clean bottle using a hose, filling up to the neck, and placed in a cool place.

After about a month, the wine is again removed from the sediment, filtered. You can add sugar to taste (2/3 to 3/4 cups per liter of wine). When it dissolves, the volume of the wine increases, so the concentration of alcohol, respectively, decreases from 15-16 to 13-14% of revolutions. The need to open the bottle during fermentation to remove foam, remove excess juice, add juice or sugar should not confuse the winemaker.

In appearance, quiet fermentation is manifested only by the fact that at first (1–2 months) bubbles of carbon dioxide are occasionally released - one at a time in 5–10 or more minutes. Gradually, the release of gas decreases more and more and, finally, stops altogether. At the same time, a thin brown layer of sediment settles on the bottom of the dishes, the wine becomes more and more transparent, its rough taste is replaced by a pleasant one, and a bouquet begins to develop in it.

Caring for the wine during this fermentation consists mainly of observing the temperature and frequent pouring of wine.

The temperature of the room in which the wine is supplied for such fermentation should be even, without sudden fluctuations and keep around 10-12 ° C. With home winemaking, of course, one does not have to be too demanding in this respect and be content with what is available on the farm. For example, you can put wine for fermentation in an unheated room, in a dry underground, in a dry basement or cellar, if it is not too cold in them and there is no danger that the wine will freeze. In a very cold (but not freezing) cellar, the wine will remain well, only its fermentation will last longer than it would have been if the temperature was within the specified standards. For fermenting wine, as a last resort, you can use the refrigerator.

Since in most cases of home winemaking there is a lack of adequate space, it is therefore more profitable to make wines that are stronger or sweeter, which are more durable and resistant to inappropriate temperatures, using the home method. Of course, in the room where the wine is fermented, clean air is needed, and neither sauerkraut nor other strongly or unpleasantly smelling products should be stored, for the wine from them will acquire an unpleasant odor and deteriorate.

Transfusion of wine during fermentation is carried out with a twofold purpose:

1) for cleaning the wine from sediment settling on the bottom of the dishes, which could impart bitterness to the wine, and 2) for airing the wine.

The latter is very important, because it accelerates the precipitation of substances dissolved in wine, which can subsequently muddy the wine. Therefore, the more often the wine is poured and aired, the more it clears and becomes transparent. If the wine is kept in glassware, then pouring and airing should be done after 1 month and even more often, because the more pouring is done, the more fully the wine will ripen and the more completely all substances that muddy it will fall out of it. They try to make transfusions so that the wine flows in a thin, long, strongly splashing stream, for better ventilation; the wine poured out during pouring is poured into a cleanly washed dish, if possible to the very cork.

If dessert or liqueur wine is being prepared, then, at the end of quiet fermentation, it is sweetened.

Filtered wine is poured into bottles and closed. Store in a dark place at a temperature of 10–20 ° C in a standing or lying position.