Understanding the environmental drivers of white winegrape quality parameters – A survey of Chardonnay ripening in Northern California

Abstract

Climate change is shifting the timing and conditions of winegrape berry ripening, impacting development and composition (van Leeuwen & Darriet, 2016). Extreme heat during ripening can alter the nuanced balance of sugar accumulation, acid degradation, and aromatic potential in berries (Pons et al., 2017). To assess the relationship between climate and Chardonnay berry composition, the development of primary metabolites and aromatic precursors over the course of ripening were tracked in 28 vineyards, spanning diverse microclimates in the North Coast wine regions of California. On-site weather stations, within-canopy temperature sensors, and stable isotope analysis (δ¹³C) provided insights into ripening conditions and their influence on the accumulation of primary and secondary metabolites. Direct assessment of the glycosidic aroma precursors using high-performance liquid chromatography–quadrupole time-of-flight mass spectrometry (HPLC-QTOF-MS) followed by suspect screening with a grape glycoside database (Caffrey et al., 2020), yielded 85 putative compounds across the sites: 36% norisoprenoids, 31% monoterpenes, 19% aliphatic alcohols, and 12% benzenoids. The incorporation of climatic data within this dataset is ongoing. This work establishes a baseline for North Coast Chardonnay precursor diversity and provides avenues for refining climate suitability indices (e.g., the Winkler Index) with finer-scale microclimatic and quality parameters to guide cultivar selection under future climate scenarios.

References

Caffrey, A. J., Lerno, L. A., Zweigenbaum, J., & Ebeler, S. E. (2020). Direct Analysis of Glycosidic Aroma Precursors Containing Multiple Aglycone Classes in Vitis vinifera Berries. Journal of Agricultural and Food Chemistry, 68(12), 3817–3833. https://doi.org/10.1021/acs.jafc.9b08323

Pons, A., Allamy, L., Schüttler, A., Rauhut, D., Thibon, C., & Darriet, P. (2017). What is the expected impact of climate change on wine aroma compounds and their precursors in grape? OENO One, 51(2), 141–146. https://doi.org/10.20870/oeno-one.2017.51.2.1868

van Leeuwen, C., & Darriet, P. (2016). The Impact of Climate Change on Viticulture and Wine Quality. Journal of Wine Economics, 11(1), 150–167. https://doi.org/10.1017/jwe.2015.21