Composition of some commercial grappas (grape marc spirit):the anomalous presence of 1,1-diethoxy-3-methylbutane:a case study

A GC-MS study of the composition of nine different grappas (Italian grape marc spirit) was carried out.High-weight alcohols showed the greatest variations, while the lower congener concentrations generally were more uniform. Particularly interesting is the presence of 1,1-diethoxy-3-methylbutane (DMB), never detected before in grappa. DMB was present in all samples, ranging from 0.8 up to 30.6 mg L-1. This latter concentration was the highest detected in an alcoholic beverage so far. A discussion on the other volatile congeners was also reported. Principal component analysis was applied to the data and explained[80% of the whole variability. Most grappas are grouped in a single cluster, while the other samples are completely separated. DMB, ethyl acetate, ethyl lactate, and n-butanol are some examples of constituent able to differentiate the tested products.