Fusel oils are called a by-product of fermentation. They are contained as an admixture in raw alcohol and have a very unpleasant characteristic odor. They are an oily liquid, which can have a color from light yellow to reddish brown. The main constituents of this substance are C3-C9 alcohols, as well as aldehydes, furfunol and fatty acids.
Aldehydes and saturated alcohols appear during the metabolism of amino acids by the yeast. Fusel oils are present, for example, in beer, as well as in moonshine, and in rather large quantities.
In home-made drinks with a high alcohol content, the problem of these impurities is quite acute. Distillation of moonshine is carried out using special equipment. Pre-cooked mash. Then it is heated to a high temperature. As a result, alcohol vapors begin to stand out. When cooled, the latter condenses and flows into a previously prepared container.
During distillation, it is very important to observe the heating mode. Light impurities contained in the Braga begin to boil at a temperature of about 68 degrees. Further, at a temperature of 78 about With, there is an intensive evaporation of ethyl alcohol. Upon subsequent heating to 85 ° C, the unwanted fusel oils themselves begin to stand out from the initial product.
Therefore, it is believed that the faster heating occurs in a moonshine still, the more efficient its operation. When distilled at temperatures up to 78 ° C, the so-called pervat is obtained, which contains a lot of harmful light impurities. Take a similar product inside, and also use it for external use, for example, in colognes or lotions, in no case be impossible. When the initial product reaches a temperature of 78 ° C., it is necessary to reduce the heating intensity. Otherwise, mash may occur. With subsequent heating, the main process of moonshine distillation itself occurs.
At this stage, you need to be extremely careful. Firstly, it is necessary to carefully monitor that the temperature of the mash does not rise above 83 ° C. Otherwise, as mentioned above, fusel oils will start to stand out from it. Secondly, at this stage, the evaporation of ethyl alcohol occurs, as a result of which its content in the Braga gradually decreases.
Ultimately, the minimum amount will remain in the original product, which can only be recovered at a higher temperature. However, at the same time, the quality of moonshine will sharply decrease, since it will increase the content of such harmful substances as fusel oils. Therefore, after reaching a temperature of 85 ° C, the distillation must be stopped. The amount of vapors of ether can be checked in a simple way. To do this, in the obtained moonshine, a piece of paper is moistened and set on fire. If it burns with a blue tint, there is still enough alcohol. If the paper does not light up, then its quantity is small. In this case, the process can be continued only for subsequent mixing with the brew and re-distillation.
Subsequently, the resulting moonshine can be further purified to remove the oils that have got into it. A variety of methods can be used for this. The simplest is the purification of moonshine with potassium permanganate. To do this, it is pre-bred in water. About 1-2 grams are needed per liter of moonshine. The resulting solution is poured into moonshine and left to stand for 10-12 hours. After clarification and precipitation, the liquid is filtered through a cloth.