⁸⁷Sr/⁸⁶Sr isotopic composition of wine: uses and limitations

Abstract

Isotopic 87Sr/86Sr fingerprints are increasingly applied to identify wine provenance, i.e., the geology of the source region. We present 87Sr/86Sr analyses of 27 samples of commercial wines from Central Europe, Southern Moravia, Czech Republic, done by thermal ionisation mass spectrometry (TIMS), and compare these data with isotopic compositions of bulk soil, bio-available soil fraction groundwater and precipitation. 87Sr/86Sr ratios of wines vary from 0.708 to 0.710 and correspond to those in groundwater and leachates from soils. We have divided the rocks (soils) into three groups according to their 87Sr/86Sr isotopic composition: (i) below that of precipitation (0.700–0.709); (ii) similar to precipitation (0.709–0.710); (iii) above that of open-area precipitation (> 0.710). We describe how bedrock from each group can affect the isotopic composition of juice, must (i.e., juice + pomace) or wine. Wines from South Moravia have very similar 87Sr/86Sr, independent of cultivars and vintage. We conclude that the groundwater sample could be used as a tracer for bio-available Sr isotopic composition. We recommend analysing the rainwater and groundwater or/and leachate from soil together with wine samples and discuss the limitations of 87Sr/86Sr use in wine as a geological tracer. We offer a simple predictive model that connects the wine-leachate-bulk rock/soil Sr isotopic composition. To interpret isotopic data correctly, careful assessment of geochemical context, i.e., isotope systematics in bedrock and soil, is necessary.

Keywords

• Central Europe
• Moravia
• loess
• soil
• Sr isotopes
• wine