Available at: https://digitalcommons.calpoly.edu/theses/3409
Date of Award
7-2026
Degree Name
MS in Agriculture - Food Science and Nutrition
Department/Program
Food Science and Nutrition
College
College of Agriculture, Food, and Environmental Sciences
Advisor
Miguel Pedroza
Advisor Department
Agribusiness
Advisor College
College of Agriculture, Food, and Environmental Sciences
Abstract
Changing Vitis vinifera ripening patterns as a result of increasing climate variability has provided challenges against the production of wines with a balanced sensory profile, with adequate acidity, color, aroma, and texture. This thesis aimed to evaluate the ripening patterns and wine profiles of potentially climate-adaptive Mediterranean varietals in two different California Central Coast climates. Additionally, different carbon-dioxide based winemaking techniques were also assessed. Viognier and Grenache Noir grapes were sourced from the warmer, diurnal Paso Robles AVA and the cooler, marine Santa Maria AVA during the 2024 and 2025 growing seasons, with Syrah and Grenache Blanc grapes being only harvested in 2024. Basic chemistry, volatile compounds, phenolics, and color were measured throughout ripening, as well as for finished wines, for which consumer acceptance was also analyzed. Paso Robles fruit ripened earlier and produced wines with greater total tannin and total phenolics concentrations. Santa Maria wines produced wines with richer color, and favored certain aroma compounds in specific varietals, such as linalool in Viognier. Vintage was a strong influence on acidity and other aroma compounds, specifically esters and ß-ionone. Next, carbon dioxide-based winemaking techniques, pressurized fermentation, and carbonic maceration, were evaluated in Viognier, Grenache Noir, Sagrantino and Syrah. Pressurized fermentations slowed the rate of fermentation but yielded similar phenolic extraction as traditional cap management in red wines. Pressurized carbonic maceration increased phenolic extraction and isoamyl acetate, while traditional carbonic maceration was defined by high concentrations of ethyl cinnamate. Overall, these Mediterranean varietals demonstrated distinguishable traits depending on region. Additionally, carbon dioxide showed to be a potential modulator of wine color, aroma, and texture in an experimental setting.