Anthony Sereni,* Elizabeth Tomasino, and James Osborne
*Oregon State University, 3051 SW Campus Way, Corvallis, OR 97331 (anthony.sereni@oregonstate.edu)

This study investigated the impact of various prefermentation treatments on sensory characteristics of Chardonnay wine, with a focus on mouthfeel. Chardonnay grapes were harvested from Oregon State University’s vineyard in September 2015. After destemming and pressing, the juice was subjected to various treatments. A portion of the juice was cold-settled for various lengths of time to produce juices with high (>700 NTU) to low (250 NTU) turbidity. Another portion of juice was settled overnight (250 NTU) and then hyperoxidized by bubbling oxygen into the juice until the dissolved oxygen measured >15 ppm (95% saturated). In addition, a portion of grapes were not immediately pressed after destemming but were soaked on the skins for 2 hr before pressing (skin contact treatment). After settling overnight, a portion of this juice was hyperoxidized (skin contact + hyper-ox). Three L fermentations of each treatment were performed in triplicate. Treatments were inoculated with Saccharomyces cerevisiae (D47) and placed in a temperature-controlled room at 15°C. After fermentations were complete, the wines were inoculated for malolactic fermentation by addition of Oenococcus oeni (Beta). At the completion of MLF, wines received a 50 mg/L SO₂ addition, were cold-settled, racked, sterile filtered, and bottled. Samples were taken and frozen at -80°C for volatile analysis. Absorbance at 280 nm (total phenolics) and 320 nm (hydroxycinnamic acids) differed among treatments. Wines that underwent hyperoxidation contained the least total phenolics while skin contact wines had the most. Hyperoxidation following skin contact reduced total phenolics. Whether these treatments modified the mouthfeel of the wines will be assessed using a winemaker sensory panel with results being analyzed by citation frequency technique.

Funding Support: Oregon Wine Board