A study of the gamma-radiolysis of the aerated ethanol-water system in a wide range of component concentrations has shown that the main process occurring in this system is selective radiation-induced oxidation of ethanol to acetaldehyde. The byproducts accumulating in the liquid phase are 2,3-butanediol and formaldehyde. The selectivity of the process increases with an increase in the alcohol content and decreases with an increase in the radiation dose. A theoretical radiolysis model created in this study is in good quantitative agreement with experimental data. Calculated product buildup curves exhibit breaking points characterized by an abrupt change in the radiation-chemical yield. Their origin is due to the complete burnout of oxygen in the closed system or its insufficiently rapid transfer to the liquid in the two-phase liquid/gas system.