Devin Rippner,* Elizabeth Gillispie, Konrad Miller, Garett Heineck, and Andrew McElrone
*USDA-ARS, 24106 N Bunn Rd, Prosser, WA, 99350 (devin.rippner@usda.gov)

The extraction of phenols during red wine fermentation is a crucial step that determines the wine’s final color and flavor. Release of anthocyanins and tannins from the grape is influenced by factors such as temperature, ethanol concentration, and fermentation conditions. It has been observed that the concentrations of skin tannin and anthocyanins decrease over time, following a first-order rate, but the release of seed tannin is at a zero-order rate, for still-unknown reasons. This research aims to understand the changes in seed morphology and internal pore structures during fermentation and how they affect extraction of phenols. The study uses x-ray microcomputed tomography to track the changes in seed morphology over time and determine their impact on phenolic extraction. A mechanistic model for diffusion of seed tannins based on internal porosity is also proposed.

Funding Support: USDA-ARS