Vessel-derived metal ions catalyze the accumulation of representative aging markers in multi-round Jiang-flavor base liquor.

Aging is indispensable for driving Baijiu toward harmony and complexity. Storage containers fundamentally shape this maturation process. However, how disparate vessel materials affect volatile evolution through distinct micro‑oxygenation and elemental leaching dynamics remains insufficiently understood. This study systematically investigated the physicochemical properties, volatile compounds, and metal ion dynamics of Jiang-flavor Baijiu across seven fermentation rounds aged for 12 months in glass bottles (GB), stainless steel tanks (SST), pottery jars (PJ), and purple clay jars (PCJ). During aging, total acid increased by 0.11 g/L ∼ 1.56 g/L, whereas total ester decreased by 0.14 g/L ∼ 0.96 g/L. Unsupervised K-means clustering revealed a granular compositional restructuring where high-abundance framework esters dropped while a representative suite of 15 minor medium-chain and long-chain esters continuously accumulated across all container systems (increased by 27.94% ∼ 119.71% and 83.34% ∼ 107.87%, respectively). Notably, ceramic-based matrices (PJ and PCJ) optimized the enrichment of these positive aging markers. ICP-MS analysis demonstrated specific element migration, with PJ aged liquor exhibiting a selective accumulation of Al3+ (0.89 mg/L) and Mg2+ (0.93 mg/L). Controlled spiking verification experiments confirmed that calibrated concentrations of Al3+, Mg2+, and Na+ exerted pervasive catalytic effects on aging marker esters. These findings provide new insights into the mechanisms of Baijiu aging and theoretical guidance for storage optimization and quality control.