One of the important places in the technology of making vodka from the very beginning of its production in the Russian occupied distillation methods of treatment. Because even in xv century, the distillation process were not so ideal to get pure alcohol without impurities and odors, Russian consumers have always tried to deliver product from the acrid smell through continual search, first of all, effective methods of cleaning grain alcohol from the impurities – fusel oils, esters, aldehydes and other substances. Since that was not covered copper-glass apparatus, to improve the distillation process was impossible. Therefore it was necessary to use different techniques to improve the quality of vodka. All of these cleaning methods divided into mechanical and biological.
For mechanical cleaning methods are: – sucks crude alcohol (ordinary bread wine) with a further strong cooling it fast – play in another vessel after settling and – filtration of crude alcohol, water-alcohol mixtures of vodka. Filtering, however, developed a long time and thoroughly. Methods filter came from generation to generation, they are constantly improving so far. Filtered through felt, cloth, felt and other materials, including charcoal. Initially used an ordinary coal, but since the beginning of the twentieth century, filtering is conducted through activated charcoal. Better absorption capacity have beech, linden, oak, alder, birch charcoal.
The first four species – are expensive and used mainly in the xviii century when a nobleman's home distillation and the manufacture of high-grade vodka. Moreover, their use is limited to certain geographic regions. Birch charcoal filter was cheap enough and is widely used in Russia for five centuries. Now the production of vodka is fully automated. At distilleries in filtering used activated charcoal, which greatly improves the quality of produced vodka.