Paul Gannett, Christian Hepburn, Marina Tacconi, Emily Stoffel, Isabelle LoMonaco, and Federico Casassa*
*Wine and Viticulture Department – Cal Poly San Luis Obispo, 1 Grand Avenue, San Luis Obispo, CA, 93407 (lcasassa@calpoly.edu)

Pinot noir (clone 667) from a coastal vineyard located in Pismo Beach (25.7 Brix, pH 3.63, titratable acidity 6.4 g/L) was made into wine with triplicate fermentations of a factorial combination of selected fermentation temperatures, ranging from Hot (25 to 32°C), to cold (8 to 16°C) and an alternation of them (cold/hot) with contrasting punch-down regimes (no punch-downs, NO PD; two punch-downs/day 12 hrs apart, PD). Anthocyanins (60% increase) and tannins (264% increase) were extracted more rapidly under Hot conditions than Cold treatment, regardless of the cap manage­ment regime. The progression of small polymeric pigments (which cannot precipitate protein) progressed steadily in all the combined treatments (albeit with faster relative formation rates in the Hot and Cold/Hot treatments than in the Cold treatments). The evolution of large polymeric pigments (LPP), which precipitate proteins, was largely impaired under the conditions of the Cold treatment, highlighting the crucial effect of alcoholic fermentation temperature on mouthfeel-active polymeric pigments. After completion of malolactic fermentation (MLF), chroma values in the Hot PD treatment (27 CIELab units), and Hot NO PD treatment (30 CIELab units) largely surpassed those of the Cold PD treatment (17 CIELab units) and Cold NO PD treatment (18 CIELab units), which concomitantly correlated with higher hue values in the Cold treatments. A two-way analysis of variance separating the effect of temperature and cap management regime on 12 chromatic and phenolic parameters pooled together after completion of MLF showed a significant effect of the temperature regime. Con­trastingly, the punch-down regime affected primarily anthocyanins, LPP, and a* (red color component). Sensory analysis of the wines is underway and will be reported.

Funding Support: World of Pinot noir Support research funds