Stable oxygen isotope content of water of EU data-bank wines from Italy, France and Germany

The application of oxygen isotope analysis to wine water (according to EU regulation no. 822/97) to determine a wine's origin, and check that it has not been adulterated is gaining increasing importance in both laboratories and industry. Using samples of Italian, French and German wines from the EU wine data bank (EU-DB), good agreement between the results from participating laboratories was demonstrated. Close correlations between the oxygen isotope contents of must and related wine water were found for samples from all countries. Based on the results of the δ18O values for EU-DB wines from 1991 to 1996 from Italy, France and Germany, we describe and discuss the main factors which are responsible for the variation of the oxygen isotope ratios of wine water. The examination of spiked samples demonstrated the usefulness of δ18O analysis for the detection of the watering down of wine. The possibility of origin assignment, preferably if the determination of the δ18O value by isotope ratio mass spectrometry (IRMS) is employed together with the determination of the site-specific hydrogen isotope content of wine ethanol by 2H-NMR and the measurement of δ13C values of ethanol by IRMS, is outlined.