Off odors in finished whiskey, such as 2-methylisoborneol (MIB) and geosmin, which impart a musty/earthy odor, can significantly impact its sensory quality, even at trace levels. Various extraction techniques paired with gas  Chromatography-mass spectrometry (GC-MS) can provide a highly sensitive analysis. However, insufficient GC resolution prevents reliable determination of MIB and geosmin because the target ions are not unique to these compounds. A Selectable 1D/2D-Gas Chromatography-Mass Spectrometry (1D/2D-GC-MS) instrument provides an effective way of improving the separation and reliability of the analysis. The enhanced separation removes interferences from the complex whiskey matrix that prevent accurate quantitation in a single-dimensional separation.