Emily Stoffel, Aude Watrelot, Sean Kuster, Tatiana Rabanales Maldonado, and Federico Casassa*
*Wine & Viticulture Department, California Polytechnic State University, San Luis Obispo, 1 Grand Avenue, San Luis Obispo, CA, 93407 (lcasassa@calpoly.edu)

Syrah wines were made into triplicate fermentations following a two-by-two factorial experimental design using the factors cap management technique (punch-downs and submerged cap) and ethanol level (control and chaptalized, 2% difference in alcohol). Additionally, half of the punch-down wines underwent a four-month extended maceration after alcoholic fermentation was complete. Submerged cap control wines had sign0ificantly higher pH and lower titratable acidity than the submerged cap chaptalized wines. Punch-down wines had 16% and 36% more anthocyanins and 54% and 42% more tannins than submerged cap and extended maceration wines, respectively. The mean degree of polymerization of tannins will be assessed in all wines at four months postpressing. According to volatile chemistry results, punchdown wines had the highest levels of esters (isoamyl acetate and ethyl octanoate) and phenylethyl alcohol than other cap management treatments, while control wines had higher isobutanol and ethyl lactate levels. Extended maceration wines had the lowest levels of total anthocyanins and tannins. Due to the low levels of phenolics seen in the extended maceration treatments, tanks underwent an additional heating protocol starting on the second month of extended maceration. There was a 23% increase in total tannins and a 3% increase in seed weight from heating. However, heat treatments on the extended maceration wines did not significantly affect the volatile chemistry profile according to solid phase microextraction results. Wines will undergo formal sensory evaluation using a modified Pivot Profile method with an expert panel of 15 winemakers. The relationship between sensory results and volatile chemistry will be assessed using partial least squares regression.

Funding Support: Funding Support: Cal Poly Baker-Koob Endowment (Cal Poly San Luis Obispo), Pacific Coast Farming (San Luis Obispo, CA)