Abstract: Exchange process between associating protons in the ethanol-water mixture system was described by NMR. A maximum appears in the dependence of exchange rate on the concentration of ethanol-water mixture system. The exchange rates, decreasing with prolongating storage period, indicate, that the more stable associated bodies have formed via hydrogen bonding between alcohol and water molecules.
The exchange process is very sensitive to the presence of contaminating H⁺ ions.
It is an important event to dvoid the presence of excess acids which may influence the stability of the associated body in ethanol-water mixture system.

Key words: Liquor, hydrogen bonding, protons exchange, NMR