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

Abstract

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 13C contents of these ethanols were determined by isotope ratio mass spectrometry (IRMS) and the 14C activity of most of these samples was determined by liquid scintillation counting (LSC). We show that the 13C content of a C3 plant such as grape vine, which strongly depends on water availability, spans nearly a 10% range worldwide. The efficiency of the 14C content of grape ethanols as a tracer of the CO2 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 13C and 14C isotopes, for detecting sophisticated adulterations is illustrated in the case of wines and brandies.