# Factors Influencing the Oxygen Isotopes of Grape Berry Water: Some Remarks

## TL;DR

This study explores how climate factors affect oxygen isotope ratios in grape water, which can help determine wine origin.

## Contribution

The study identifies a linear correlation between grape must water isotopes and evapotranspiration, offering a new method for wine origin tracing.

## Key findings

- A linear correlation was found between δ18O of grape must water and evapotranspiration in specific Italian regions.
- The intercept of the correlation estimates isotopic features of water absorbed by plants during grape ripening.
- Climatic parameters influencing oxygen isotope variation in grape must water were identified using correlation coefficients.

## Abstract

Several chemical and isotopic methods have been suggested for tracing the wine origin in relation to the climate/meteorological conditions of the vineyard areas. IRMS (Isotope Ratio Mass Spectrometer) is one of these tools. In the Oltrepò Pavese (Lombardia Region, Pavia Province, Italy) and in the Illasi/Mezzane areas (Veneto Region, Verona Province, Italy), for the harvests of 2021 and 2022, a linear correlation between δ
18O of the grape must water (δ
18Om) and the potential evapotranspiration (ETO) and crop evapotranspiration (ETC) has been found. ETO and ETC were calculated according to the FAO‐56 model using meteorological data from the meteorological stations located close to the vineyards studied. We can state that the intercept obtained for the linear correlation δ
18Om on ETC is an estimate of the isotopic features of the water absorbed by plants during the late stage of the grape ripening. The obtained data allowed us to estimate the isotopic enrichment factor ε
18Om−PW (m = grape must water and PW = precipitation water), which depends on climatic/meteorological conditions. Subsequently, the climatic parameters that mostly influence the oxygen isotope variation in grape must water have been identified using a correlation coefficient.