Why homemade wine stopped fermenting

People involved in home winemaking sometimes encounter such a problem when the fermentation of wine must suddenly stops. In this case, it is quite difficult to determine why fermentation stopped, because such an incident can happen even if all the technology for making homemade wine is followed. BUT this problem is quite serious, because it can lead to damage to all wine material, which means that the work of the winemaker will go down the drain and the products can be thrown away.

To decide what to do in such a situation, you first need to find out why the wine stopped fermenting in a particular case. What factors can provoke a stop in the fermentation of homemade wine, and how this process can be resumed – this will be the article.

Features of the fermentation process

The technology for making homemade wine can be different, besides, various products can be used in winemaking: fruits, berries, grapes. But anyway homemade wine must go through the fermentation process, otherwise the juice of fruits and berries will not turn into a wine drink.

Wine or yeast fungi are responsible for the fermentation of fruit juice. Typically, such fungi are found on the peel of fruits and berries, and are a whitish or grayish coating.

These fungi feed on sugar, in the course of their life they process sugar, turning it into alcohol – this makes the juice an alcoholic drink. In addition to alcohol, carbon dioxide is produced during the fermentation process, it is he who inflates gloves on bottles of wine or comes out in the form of air bubbles from under the water seal.

Natural sugars are found in almost all fruits or berries, only their amount can vary. For winemaking, those products are suitable that have a fairly high content of natural sugar in the form of glucose, sucrose and fructose.

The sugar content of fruits and berries may depend on factors such as:

• crop variety;
• ripeness of fruits or grapes;
• fruit picking time;
• fruit aging time in the interval between harvesting and laying wine.

To make high-quality homemade wine, it is recommended to collect only fully ripened fruits and berries, do it on time, prefer varieties with high sugar content in fruits (the taste of fruits should be more sweet than sour).

Insufficient natural sugar content of products forces winemakers to additionally use granulated sugar. The difficulty lies in the fact that it is very difficult to calculate the right amount of sugar, so it is better to immediately take moderately sweet fruits and berries for homemade wine.

Why house wine does not ferment

Not only beginners, but also experienced winemakers can face the problem of stopping the fermentation of homemade wine. And wine may not initially ferment, or it may suddenly stop fermenting. There may be several reasons for this, all of which require a special solution.

Why homemade wine can stop fermenting:

1. Too little time has passed. Wine fungi need time to start their work. The speed of yeast activation depends on several factors, among which are: the sugar content of the wine, the type of raw material, the temperature of the must, the type of starter or the type of fungus. In some cases, the wine may begin to ferment a couple of hours after the bottle has been closed with a water seal. And it also happens that fermentation begins only after three days. Both of these situations are normal, but the winemaker should start to worry when the wine has not fermented for more than three or four days from the moment the must is fermented.

   

2. The wine container is not airtight. The fact is that normal fermentation of homemade wine should occur with complete sealing of the product, that is, outside air should not enter the wine. For wine, it is not the air itself that is dangerous, but the oxygen contained in it. It is oxygen that causes the wort to turn sour, and the wine eventually turns into wine vinegar. It often happens that the winemaker thinks that his wine is not fermenting, as he judges by a deflated glove or the absence of bubbles in the water seal, but it turns out that the bottle is not hermetically sealed. As a result, carbon dioxide escapes from under the cap or under the elastic band of the glove, so it is deflated. Wine, nevertheless, wanders, it’s just not visible. It would seem that there is nothing dangerous in such a situation, but it is not. The fact is that at the end of the process, fermentation weakens, the pressure of carbon dioxide becomes not so strong. Because of this, oxygen from the air can easily get inside the container and spoil everything that is already almost fermented wine.

   

3. Temperature fluctuations. For normal fermentation, the wine must be in a room with a temperature of 16 to 27 degrees. Fungi live and work until the temperature of the wine drops below 10 degrees and rises above 30. In case of cooling, the yeast “falls asleep” and precipitates, and if the wine is overheated, the fungi simply die. They also do not like wine fungi of temperature fluctuations: wine will ferment well only at a stable temperature.

   

4. Violation of sugar content. Permissible limits for the percentage of sugar in wine are from 10 to 20%. If these boundaries are violated, fermentation will stop. With a decrease in sugar content, the fungi have nothing to process, turning all the sugar in the wort into alcohol, they die. When there is too much sugar in the wine, the yeast cannot handle the amount and the wine is preserved.
5. “Non-working” yeast. Most winemakers use wild yeast, that is, those found on the skins of fruits and berries, to make homemade alcohol. Wild fungi are very unpredictable, they can develop vigorous activity at first, and then abruptly stop the fermentation of wine. Perhaps this is also with an insufficient amount of yeast, when the fruits were washed or it rained on the eve of the harvest, for example.

   

6. The density of berry or fruit juice. Some wine products, such as plums, currants, mountain ash, are very difficult to give juice, after crushing they form a thick puree. It was found that the thicker the must, the more difficult it is to ferment.
7. Mold. When preparing homemade wine, it is very important to observe complete sterility: containers, hands, products. In order not to infect the wine with mold fungi, all dishes must be sterilized and washed with soda. Do not put rotten or spoiled products in the wort, they can be infected with mold. Moreover, the use of material on which there are already traces of mold is not allowed. Therefore, before making wine, berries and fruits are carefully sorted out.
8. Natural end of fermentation. When the alcohol content of wine reaches 10-14%, the wine yeast dies. Therefore, homemade wine cannot be stronger (unless it is fixed with alcohol, of course). Most often, the fermentation of homemade wine lasts from 14 to 35 days, after which the process gradually slows down until it stops completely. You can find out about this by the appearance of sediment at the bottom of the bottle, the clarification of the wine itself and the absence of bubbles in the design of the water seal or a deflated glove.

   

What to do to ferment wine

Having found out why the wort stopped (or did not start) fermenting, you can try to correct this situation. Methods for solving the problem depend on the cause.

So, You can make wine ferment in the following ways:

• strengthen the tightness of the lid or water seal. To do this, you can use batter or other sticky mass, which coat the neck of the bottle at the point of contact with the lid or glove. Open the bottle less often, and if you do, then only for a few minutes.
• Provide the wine with a constant suitable temperature – from 16 to 27 degrees. If the must is overheated, you can try adding some special wine yeast to it – fermentation should start again.
• If the wine has not started to ferment within four days and it looks too thick, you can try thinning the must by adding a portion of sour juice or water to it. The liquid should be no more than 15% of the total volume.

  

• Check the sugar level with a special device – a hydrometer. If there is no such tool at hand, the wine is tasted: it should be sweet, like tea or compote, but not cloying (like jam, for example) and not sour. Sugar can be added no more than 50-100 g for each liter of juice, otherwise fermentation will not start. It is better to add granulated sugar fractionally, in small equal parts with an interval of several days. So the fungi will process the sugar gradually, which will prolong the fermentation of the wine.

  

• When the reason for stopping fermentation is low-quality yeast or an insufficient amount of it, you need to add a fresh portion of fungi. They can be found in special starter cultures, store-bought wine yeast, quality raisins, or a few unwashed grapes. These components are added to the wort and mixed.

This can be done in several ways: add alcohol to the must, take the bottle to a room with a temperature below 10 degrees, heat the wine to 35-55 degrees (this process is called pasteurization). In all these cases, the fungi die and fermentation stops.

If homemade wine has stopped fermenting, this is not a reason to pour it out – the situation can be corrected. First of all, the winemaker must find out why this happened, where he violated the technology, and then take appropriate measures.

There are also cases when it is impossible to help the wine. Then it remains to learn from your own mistakes in order to avoid them in the future.