Improving the aging aroma profiles of Italian Riesling and Petit Verdot Wines: Impact of spontaneous and inoculated fermentation processes

•Using spontaneous fermentation without inoculated yeast or any auxiliaries.•Using GC-IMS to distinguish the differences between two fermentation styles.•The complex and persistence of spontaneous fermentation’s aroma were increased.•Compared with inoculated, spontaneous fermentation showed expressiveness of terroir.•Spontaneous fermentation increased the aging potential of both varieties of wine. The study employed gas chromatography-ion mobility spectrometry to differentiate between wines undergoing spontaneous fermentation and inoculated fermentation, with aging periods of 3, 9, and 15 months. The results indicate that throughout the three aging periods, there was a notable increase in the levels of ethyl hexanoate (Monomer, M), 2-methyl butanal, ethyl octanoate (M), ethyl octanoate (Dimer, D), propyl acetate, and 3-methylbutanal in the spontaneous Italian Riesling wine (RS). Furthermore, the compounds isoamyl acetate (M), ethyl formate (D), 4-methyl-2-pentanone (M), and ethyl formate (M) demonstrated the highest concentrations at 15 months in RS, accordingly, these compounds displayed a consistent upward trend throughout the aging period. A total of 14 volatile compounds exhibited an upward trend from 3 to 15 months in the spontaneous fermentation of Petit Verdot Wine (VS). Subsequently, these compounds attained their maximum levels. Spontaneous fermentation effectively enhances the aromatic characteristics of wines, consequently improving their capacity for aging.