MEASURING C-14 CONCENTRATION IN WINE TO MONITOR GLOBAL DISTRIBUTION OF C-14

Using liquid scintillation counting (LSC) and accelerator mass spectrometry (AMS), radiocarbon concentrations were measured for wine from 8 wineries located in 7 countries in the Northern and Southern hemispheres. The C-14 concentrations of ethanol and residual materials in the wine were correlated (correlation coefficient 0.82). The Delta C-14 measurements of wine samples from the mid-latitudes in the Northern Hemisphere were approximately 11% lower than the extrapolations from Schauinsland data, suggesting a local fossil fuel effect. Delta C-14 measurements from the wine samples from the Southern Hemisphere were higher than those from the Northern Hemisphere. The offsets of the 4 wine Delta C-14 measurements were significant, with values between approximately 8% and 15%. Because the harvest years of the mixed grapes were estimated to be 7-12 yr older than their vintage years, this leads to a caveat when determining the C-14 concentrations of the year using the wine vintage.