The invention relates to a method for assessing the quality of alcoholic products, applicable in the field of the alcohol industry, catering, and the entertainment business, and in particular for quantitatively determining the methyl alcohol content in various alcoholic beverages—for example, whiskey, vodka, liqueur, rakia. According to the proposed method for assessing the quality of alcoholic products, a 5 MHz disc-shaped quartz resonator, acting as an alcohol sensor, is placed in a cylindrical Teflon holder (3) mounted on the lid of a glass container (1) filled with 100 ml of a given alcoholic beverage (2) - for example, whiskey, and the active sensor surface, coated with iron phenoxide, is exposed to saturated alcohol vapors, with changes in the resonance frequency of the device being monitored and recorded in real time by a frequency meter (5) and a desktop computer (6), and represent an indicator of the presence of a methyl fraction when there is a clear difference in the numerical readings of the sensor compared to a reference sample of pure ethyl alcohol. The main advantages of the proposed method are related to the operation of the sensor in a thermostated environment with saturated vapors and equilibrium vapor pressure, which eliminates the need for hoses, valves, and flow meters, which introduce uncertainty in determining the concentration of gases entering the working chamber. The miniature dimensions of the quartz crystal—25.4 mm in diameter and 0.3 mm thick—allow for integration into portable devices for out-of-laboratory analysis of alcohol quality. The innovative nature of the invention lies in the hydrophobicity of the adsorbent, which ensures high selectivity of the method and minimizes the impact of ambient humidity and interfering chemical fractions on the device readings. The method for assessing the quality of alcoholic products, based on a piezoresonance sensor coated with a layer of iron phenoxide, can find wide practical application in the alcohol industry, restaurants, and the entertainment business for the non-laboratory determination of methanol content in alcoholic beverages, with the aim of preventing poisoning and deaths in the production or accidental consumption of low-quality alcohol.
