Multimodal Analysis of Oak Wood Metabolites for a Comprehensive Understanding of the Aging Process in Typical French Spirit Barrels

Oak wood plays a crucial role in barrel aging, significantly influencing the flavor, aroma, and quality of aged spirits. This study integrates liquid chromatography–tandem mass spectrometry (LC–MS/MS), laser desorption/ionization mass spectrometry (LDI-MS), and time-of-flight secondary ion mass spectrometry (TOF-SIMS) to analyze metabolite distribution in oak wood. By comparing freshly cut wood, freshly toasted wood, or historical wood staves of 2- to 50- or 100-year-old, this multimodal approach reveals spatial distribution changes in lignin, polysaccharides, lipids, and extractable compounds such as phenolic ones. Notably, the degradation of polysaccharides and migration of ellagitannins are observed, providing new insights into wood-aging dynamics. These findings offer potential improvements in barrel aging techniques to enhance the sensory profile of spirits.