Juel Peter Hernandez and Federico Casassa*
*Wine and Viticulture Department, Cal Poly San Luis Obispo, 1 Grand Avenue, San Luis Obispo, CA 93407 (lcasassa@calpoly.edu)

Three Pinot noir clones (2A, 115 and 777) grown in the Edna Valley AVA were made into wine by conducting triplicate fermentations of selected winemaking techniques. In addition to an untreated control, fruit from each clone was subjected to both extended maceration for 30 days (EM) and stem addition at a 100% rate. Prior to stem addition, stems were ozonated and microwaved (10 min to 45°C), and placed at the bottom of the fermentors (MW + Stems). The clone 115 wines had 32% less anthocyanin content than 2A or 777. MW + Stems and EM decreased anthocyanins by 9% and 21%, respectively, relative to control wines. Tannin content was the most affected variable impacted by the treatments, with early effects carried over post malolactic fermentation.  At day 120, MW + Stems and EM increased tannins by 732 and 772%, respectively. Wines from clone 2A were negatively impacted by EM and MW + Stems in respect to polymeric pigment formation, while clone 115 responded favorably to the MW + Stems treatment, and clone 777 responded favorably to both MW + Stems and EM. This trend was also mirrored by corresponding positive effects of MW + Stems and EM on wine color at day 120, but only for clones 115 and 777. Confirming these observations, a two-way ANOVA revealed that the only significant treatment × clone interactions were for parameters associated with polymeric pigment formation. On the other hand, absence of significant treatment × clone interactions for the remaining phenolic parameters suggests that both MW + Stems and EM affected the extraction of anthocyanins and tannins in a similar way, irrespective of the clone. Clone 2A seems to be the less responsive clone to the applied winemaking techniques from the perspective of color, phenolics, and polymeric pigment formation, although EM and particularly MW + Stem caused a dramatic increase in the tannin content of the final wines.

Funding Support: Agricultural Research Institute (ARI). George Donati and Jim McGarry (Pacific Vineyard Co) are acknowledged for generous donation of the fruit for this project and outstanding support with sampling and harvest logistics