Maisa Lima, Desmon Hernandez, and Ron Runnebaum*
*University of California – Davis, 595 Hilgard Lane, Davis, CA 95616 (rcrunnebaum@ucdavis.edu)

Correlations between vineyard site and wine are historically limited due to lack of continuity across multiple vintages, lack of uniformity in scion clone, and lack of controlled pilot-scale winemaking conditions. We determined the elemental composi- tion characterizing wines from four vintages (2015 to 2018). The experimental design aimed to minimize sources of potential variation by using a single scion clone and automated 200-L fermentation vessels at the UC Davis Teaching and Research Winery, in which fermentations are highly controlled across vineyard replicates, vineyards, and vintages. Grape clusters were hand-harvested from vineyards that span a distance of >1400 km. American Viticultural Areas (AVAs) represented included Santa Rita Hills, Santa Maria Valley, Arroyo Seco, Carneros, Sonoma Coast, Russian River Valley, Ander- son Valley, and Willamette Valley. Fruit was destemmed only and inoculated with Saccharomyces cerevisiae yeast. Upon completion of inoculated MLF, wines were stored in stainless steel vessels until sampling for characterization. Forty-seven elements were profiled in a mass range of 7 to 238 m/z by using inductively coupled plasma– mass spectrometry. Principal component analysis was used to characterize vineyards using only significant elements identified by an analysis of variance measuring effects of vineyard. AVAs were generally separated by elemental composition profile, such as Santa Maria Valley and Arroyo Seco. Some vineyard locations, however, were more similar in elemental composition to sites in other AVAs than to those within their AVA. Differences in profiles within an AVA suggest that factors such as unique soil composition or conditions or microclimate may have an effect. Overall, separation and clustering of wines by elemental composition appears consistent across vintages in this experiment. Details to be unraveled include confirming the consistency of elemental profile from sites across vintages and correlations with wine chemistry and sensory profile.

Funding Support: Jackson Family Wines