Fermentation in practice

Fermentation in practice

The yeast undergoes the fermentation process, however, you probably don't know everything about it. Alcohol fermentation is, in fact, a process, which is only apparently simple. If you are going alone Apple cider apple glass bottle on the tableproduce any alcohol, it would be good, if you knew as much as possible about fermentation, so that you can consciously influence its course.

The basis of the basics

Alcoholic fermentation, that is, the reaction of the enzymatic breakdown of glucose, is described by the so-called Gray-Lucas equation. It shows so much, that this process releases a lot of energy (including a large amount in the form of heat), and the production of ethanol alcohol and carbon dioxide. If we were to analyze the stoichiometry of the reaction equation, it would turn out, that with everyone 100 g of sugar yeast can produce just over 51 g of alcohol. But remember, it's just a theory.

Practical equation of fermentation

The production of alcohol is only a sideline for yeasts (moreover, often undesirable) the effect of fermentation. Its main purpose is to release the energy of chemical bonds of glucose. How much does it mean for a winemaker or a brewer? But in practice, not all sugar will be converted to alcohol. The losses will be due to various metabolic processes, as well as the volatility of alcohol solubility in environments containing a lot of carbon dioxide. Experimentally designated, that about a tenth of the sugar is not converted into alcohol, which allows you to determine the amount of sugar, from which one liter of alcohol is made, on 1,7 kilograms.

The problem of organic chemistry

If you have a basic understanding of organic chemistry, you may know that, that compounds with an identical summary formula may look different. This causes, that through various chemical processes, glucose can be converted into other compounds, not necessarily desirable, although the stoichiometry of the equation will still be consistent. This is also how all biological processes work: the equations only remain on paper, and nature works differently. Therefore, various compounds can be formed during fermentation, the presence of which in the mixture gives it a bad taste. The mixture of these undesirable substances is called fusel oil, and it includes, among others: amyl alcohol, propyl and isobutyl, and also esters, ketones and aldehydes. Various other substances will also be found in the solution, which are released into the environment in the event of perforation or autolysis of yeast cells.

To prevent the formation of fusel oil, first of all, the fermentation temperature for yeast should be lowered. It is recommended to keep it at approx 20 degrees. In fact, yeast can withstand temperatures up to twice as high, but not counting the formation of fusel oil, temperature should not be allowed to rise for one more reason: the higher it will be, the faster the yeast will die. A high concentration of alcohol only speeds up this process, because it sensitizes yeast to temperature increases.

Oxygen? Best not

Fermentation is a method of anaerobic respiration, therefore, as the name suggests, generally the oxygen supply to the fermentation vessel should be shut off. Of course, small amounts of it are not dangerous, on the other hand, too high an oxygen content may adversely affect yeast. Specially shaped canisters and additional elements cause, that as little oxygen as possible enters the fermentation vat, which additionally dissolves poorly in a warm mixture, so there are strictly anaerobic conditions at the bottom. This is a guarantee of good taste and proper fermentation, therefore, you should think about sealing all joints in advance.