This Application Note describes both HPLC and UHPLC methods to simultaneously separate and identify seven tannin compounds as aging markers in barrel-aged alcoholic beverages. The proposed methodology was applied to four different matrixes: whisky, brandy, rum, and tequila, to demonstrate a correlation between aging time and total tannin concentration level. Such a methodology could easily lead to an authenticity verifi cation method to be implemented at the manufacturing process as a quality control measurement, preventing frauds or adulteration.