The paper gives the analysis of ethanol dehydration by using a solid adsorbent, which is capable of forming crystalline hydrates by means of chemical bonding of water molecules with its further formation. The main objective of the research was to study the process of crystalline hydrates formation, as well as another type of interaction with water — hydrolysis. Ethanol, almost free from water, was obtained using one of the salts of phosphoric acid — sodium hydrogen phosphate, containing one hydrogen atom and two atoms of sodium. Thus, the selection of sodium hydrogen phosphate as a salt was due to its ability to form crystalline hydrates of several compositions. To confirm this phenomenon, the volume fraction of ethanol depending on the time was analyzed. As expected, the results showed gradual formation of crystalline hydrates of various compositions. The volume fraction of water was measured during the study by Karl Fisher titration. The research results can be used primarily in the manufacture of biofuel for transport vehicles. Thus, the use of solid-phase adsorbents can provide dehydration of ethanol to almost dewatered state. Herewith, there is no need to use sophisticated equipment (e.g. to shift the azeotropic point) for water distillation, or to shift the azeotropic point of water, for example, by introducing a third component — benzol. The analysis of ethanol dehydration allows selecting the most effective length of time for dehydration.