The lifetime of a single bubble on the surface of an alcohol-water liquid bath is measured at intermediate humidity rates. Thanks to an automatic bubble generation device associated with a lifetime measuring device, we carry out a statistical study of the bubble lifetime, which extends over three decades, from 0.1 to 100 s. Up to alcohol concentrations of 12% (g/g), the average bubble lifetime increases with the alcohol concentration. In addition, normalized lifetime probability density functions are independent of the alcohol concentration and relatively well described by a Weibull distribution with an exponent of 4/3. We compare our experimental data with the predictions of a recent model highlighting the importance of Marangoni stresses induced by water contaminants to the fate of a bubble. In our case, these Marangoni stresses are probably induced by heterogeneities in the alcohol concentration maintained by evaporation.