Spatial and Temporal Dependence of the 13 C and 14 C Isotopes of Wine Ethanols

More than 1000 authentic samples of ethanols were extracted by quantitative distillation from vintage wines and brandies prepared from grapes harvested in well-defined regions and years. The 13 C contents of these ethanols were determined by isotope ratio mass spectrometry (IRMS) and the 14 C activity of most of these samples was determined by liquid scintillation counting (LSC). We show that the 13 C content of a C 3 plant such as grape vine, which strongly depends on water availability, spans nearly a 10% range worldwide. The efficiency of the 14 C content of grape ethanols as a tracer of the CO 2 turnover after the peak of the nuclear test in the 1960s is also discussed in terms of geographical effects. Finally, the necessity of a multi-isotopic approach, including 13 C and 14 C isotopes, for detecting sophisticated adulterations is illustrated in the case of wines and brandies.