Acidifying the settings - what you need to know?
The fermentation process is only apparently a simple one. From a biological point of view, the contents of the fermentation vessel are a very complex ecosystem and controlling the processes taking place in it requires a lot of effort.. A lot of attention should be paid to, among other things, acidification.
- The basis of the basics
The pH of the mash can be different. However, a value within the limits is recommended 4,8 do 5,3. Admittedly below and above this range, fermentation will take place, but keep in mind, that it will not necessarily be the dominant process then. What does this mean in practice? So much, that the yeast would not be able to ferment the added sugar or that other organisms would develop in addition to it, which will hinder the growth of yeast and spoil the taste of the alcohol.
- What happens outside the optimal range?
Yeast, similarly to all organisms, they react in a certain way to changes in the environment. At the cellular level, this manifests itself in an alteration of the metabolic pathways in this way, that they counteract change, which causes them. So much from a scientific point of view. In fermentation reality, lowering the pH, that is, an increase in the acidity of the solution will increase the secretion of glycerin and aldehydes. This is a favorable phenomenon, but only then, when it runs at a certain speed and capacity. Other aldehydes are already produced in a more acidic environment, whose taste and aroma are by all means undesirable.
The lower pH directly affects the yeast, by inhibiting even some basic biochemical processes, which means yeast cell death. The optimal pH range does not harm the yeast, it creates an unfavorable living environment for pathogens, including many bacteria, that could ruin your settings.
The yeast dies as the pH rises, unwanted microflora develops, and fermentation, if it runs at all, it causes many by-products.
- How it is done in practice?
There are several ways to lower the pH of the setting (it will initially be slightly lower than 7). The most popular is to add citric acid to the water in an amount of about 5 g each 10 liters of setting. Acidification is carried out once. Also remember, that any fruit addition will lower the pH, and this is due to the content of organic acids in plant cells (apple, lemon and others).
In the further stages of fermentation, no treatment is required - the yeast automatically maintains the desired pH, on the other hand, the appropriate plugging of the ladle prevents the penetration of substances from the outside. Carbonic acid and water autolysis are responsible for maintaining acidity during fermentation, which are sufficiently effective in retarding the increase in pH, so that it remains within the yeast tolerance until the very end.
- What you will need?
You can buy ready-made acidulants based on citric acid, but you might as well handle ordinary food grade citric acid. Just remember to get a litmus strip or a pH meter. This allows you to properly determine the acidity of the solution, and the yeast tolerance range is not very broad after all, so do it as accurately as possible.
Important note - the acidification stage should not be skipped. At home, it is not possible to clean the fermented liquid from various undesirable substances - in industrial methods, slight differences in taste resulting from pH deviation from the norm and changes in bioactivity, can be eliminated by various purification techniques (e.g.. during distillation, rectification), and at home it is much easier to prevent such pollution.
Found on google via phrases:
- wine acidification