Why thick foam appears during wine fermentation and 4 ways to solve the problem

The foam that forms on the wort during fermentation is normal. But this only applies to foam of a certain intensity. If the wine froths more than usual, this indicates that there are violations in the process. Find out the reason. Consider why wine foams a lot during fermentation and how to solve this problem when making wine at home.

Danger of increased foaming

The presence of foam indicates the yeast is working. If everything goes well, the normal height of the foam layer during fermentation is 3-15 cm. If the foam rises too high or takes up the entire free space of the bottle, or even comes out through the water seal tube, this means that the correct fermentation conditions are not met.

The stage of active fermentation begins 6-18 hours after the addition of yeast. It lasts 7-12 days. In the process of active fermentation, a lot of carbon dioxide is released, which is why foam is formed. It is in the stage of active fermentation that the problem of increased foaming may appear. Then the yeast moves down from the top layer of the wort, and the foam becomes less.

Expert opinion

Zarechny Maxim Valerievich

Agronomist with 12 years of experience. Our best summer cottage expert.

The danger of strong foaming is not only that some of the liquid, together with the foam, may end up outside the bottle, but also that the fermentation is not going well, which will certainly affect the quality of the finished product.

Foam trapped in the tube can clog it, the gas cannot escape and will accumulate in the container. The pressure in it will increase, in some cases it can knock out a water seal or even rupture the container. If this does not happen, food that should have been removed will remain above the wort and spoil its taste and smell. Fermentation may stop.

Why wine foams

If the wine has a lot of foam when spilled, this may be normal. You need to wait 2-3 hours, if the layer does not rise, then everything is in order. Foaming depends on several factors:

  1. Raw materials. Juice from plums, pears and cherries gives a lot of foam. Grape and apple juice - less. The color of the foam also depends on the type of fruit and berries.
  2. Yeast species. Special wine yeast promotes less foaming than wild yeast, which is on the surface of the fruit.
  3. Temperatures. If the temperature in the room where the bottle with the wort is located is higher than the required temperature, then the process is accelerated, and a thick foam appears.

To control the situation, you need to follow these criteria.

Ways to solve the problem

There are several ways to stop foaming and reduce the build-up. Each of them is applicable in a specific situation.

Do not stir the wort, after that it will foam even more actively. The right conditions for wine fermentation: constant room temperature, without sudden jumps, from which the activity of the yeast changes. There should be no drafts, the container should be in a dimly lit or dark place. Under the influence of ultraviolet light, part of the alcohol turns into acetic acid, which reduces the degree and makes the wine sour.

Split the wort

This method works when a container was originally used, in which there is little free space left after the infusion of liquid.

If the free space is less than a third, you need to pour some of the juice into another container. Install on each odor trap.

Remove foam

According to this method, you just need to remove some of the foam from the top. The method has a disadvantage - yeast is removed along with the upper foamy layer. Therefore, it is necessary to remove it carefully so as not to stop fermentation.

Lower the temperature

The normal temperature that needs to be maintained for proper fermentation is 18-24 ° C. It is in this range that the wine-making process proceeds correctly. But if the temperature reaches 30 ° C and higher, the yeast multiplies too actively and emits a lot of carbon dioxide, alcohol formation goes faster. At 16 ° C and below, yeast activity decreases and stops. In any case, both high and low temperatures adversely affect the process and quality of the drink.

To reduce the intensity of foaming, the temperature must be lowered to 16-20 ° C. This will normalize the process. It is possible to increase the total duration of fermentation, but the quality of the finished wine increases. It will taste better, will not be cloudy, and will acquire a beautiful color. Indicators such as clarity, viscosity, color and taste depend on the temperature at which fermentation took place.

Restart fermentation

This method should only be used if there are third-party yeasts in the wort that are highly foam-raising. The reason can also be determined by the presence of a smell that is not emitted during normal fermentation, by the viscosity of the wort, by an unpleasant aftertaste.

Corrective measures: drain the juice from the sediment, warm up to 65-70 ° C (if possible, without air access) for 3-5 minutes. After cooling the heated liquid to 20-24 ° C, pour it back into the container, add wine yeast or sourdough and put a water seal. Warming up allows you to destroy unwanted microflora, and the addition of the starter culture allows you to add the necessary microorganisms to the wort.

Intense foaming in homemade wine is normal only if the layer does not exceed the specified height. If more foam is formed than necessary, then it is worth finding out the cause and proceeding to eliminate it.

Most often, the reason lies in the wrong conditions, so you need to adjust them. It is important to pay attention to the quality of yeast, ideally, you need to use special wine, which correctly regulate fermentation. Or carefully prepare the raw materials, wash the fruits, berries, sterilize the container and the closure so that they do not leave undesirable fungi and yeast on them.

Watch the video: How to Brew like a Pro: Dealing with Stuck Fermentation (June 2021).