Correlations between vineyard site and wine have historically been limited due to lack of uniformity in scion and rootstock clone and lack of controlled pilot-scale winemaking conditions, particularly temperature. Our work aims to minimize these sources of variation by using a single combination of scion and rootstock. In addition, we maintained highly controlled fermentation conditions by using automated 200-L fermentation vessels at the UC Davis Teaching and Research Winery. Clusters were hand-harvested from 10 vineyards comprising the same combination of scion, Pinot noir clone 667, and rootstock 101-14 Mgt. The vineyards were planted at locations spanning a distance of more than 650 km and represented the Santa Maria Valley, Arroyo Seco, Carneros, Sonoma Coast, Russian River Valley, and Mendocino American Viticultural Areas (AVAs). The fruit was destemmed into fermentation vessels and inoculated with a strain of Saccharomyces cerevisiae. These vessels offer a high degree of automated temperature control, facilitating uniform fermentations. After primary fermentation, wines were inoculated with a strain of malolactic bacteria. Upon completion of MLF, wines were sampled for analytical characterization. Data characterizing wine phenolics were obtained using high-performance liquid chromatography (HPLC). The data were analyzed using analysis of variance (ANOVA) measuring for the effects of vineyard. Approximately 20 phenolic compounds were identified that significantly differentiated the wines. The compounds included hydroxycinnamic acids, flavan-3-ols, flavonols, and anthocyanins. Principal component analysis (PCA) was used to characterize vineyards using only significant compounds. By minimizing variation in scion/rootstock combination and in fermentation, AVAs could be separated by their phenolic compound profile; however, some vineyards within an AVA had dramatically different profiles. These results suggest that factors such as unique microclimates or soil conditions may have an effect. These details will be explored in future work as will the consistency of phenolic compounds from these sites in subsequent vintages.

Funding Support: Jackson Family Wines