This paper reports on a quick and simple method for reliably quantifying aroma precursors in grape extract, musts and wines of different grape varieties. The method, which is intended mainly for use by wineries and analytical laboratories, is based on isolation of terpenyl-b-D-glycosides through selective retention on a C 18 reversed-phase column, followed by hydrolysis to liberate terpenes, yielding an equimolar proportion of free aglycons and glucose. Sugar was measured using an enzyme analysis kit. Aroma precursors were quantified using this method, in a range of crushed grapes, musts and wines produced in the Castilla La Mancha region. The method was also applied on a larger scale in a wine analytical laboratory, to chart the behavior of terpenyl glycosides during the final stages of ripening of grapes from different viticulture Spanish regions. The results obtained provided a reliable indication of the aroma potential of the varieties studied. The method is simple, practical and readily applicable in wineries.