Microbial and aroma characteristics of spontaneously fermented wine from organic grapes at the eastern foot of the Helan Mountain

Organic management practices and spontaneous fermentations have become focal points in wine research due to increasing consumer interest in healthy foods and sustainable agriculture. In this study, ‘Cabernet Sauvignon’ grapes sourced from organic and conventional management vineyard (OMV/CMV) in the Ningxia region were subjected to spontaneous fermentation. The microbial, oenological, and aroma profiles of grape must and resulting wines were assessed using high-throughput sequencing (HTS), high-performance liquid chromatography (HPLC), gas chromatography with mass spectrometry (GC-MS), and sensory evaluations. Network analysis was applied to explore relationships among microorganisms, volatile compounds, and aroma attributes. Results showed that organic management significantly increased microbial species richness, α-diversity, and the variety and concentration of aroma compounds, favoring the production of natural wines with complex aroma profiles. Relative abundance of Saccharomyces in OMV reduced, promoting the prevalence of other yeast species during fermentation. Bacterial succession in wines from OMV remained stable, with Pantoea as the dominant genus. Among oenological parameters, OMV wines significantly induced glycerol content, while reduced total acidity, tartaric acid, and citric acid content. These wines exhibited significantly higher levels of fermentative (+16%) and varietal (+72%) volatiles, as well as enhanced floral and sweet fruity aromas, along with distinct nail polish and vegetal notes. Additionally, Saccharomyces, Hanseniaspora, Metschnikowia, and Pantoea were strongly correlated with specific volatile compounds and aroma characteristics. This study provides valuable data that can inform spontaneous fermentation practices and guide vineyard management for natural wine production.