The evolution of supported silver species of a pre-calcined Ag/Al2O3 catalyst was monitored upon thermal treatment under an air flow enriched with 3000 ppm of ethanol (EtOH) using transmission electron microscopy and UV-visible and X-ray absorption spectroscopies. A special focus is put on the application of in situ Quick-XAS that permits to acquire high quality spectra at the Ag K-edge with a good time resolution (30 s), thus informing in real time on the transformations of the silver species. While the reduction of silver under Air/EtOH flow is shown to possibly occur at room temperature, the process is strongly accelerated by heating, most of the silver being indeed reduced at ca. 78 °C, a temperature which corresponds to the ethanol boiling point. The possible impact of this silver sensitivity on the behavior of silver-alumina catalysts in reactions such as the selective catalytic reduction (SCR) of NOx in presence of ethanol is addressed.