Lisa Robbins (Advisor Dr. Joseph Scheerens)
“The Effects of Hyperoxidation and Storage Temperatures on the Flavor Profiles and Sensory Quality of Riesling Wine”
Most Ohio wineries produce white wines from cultivars with fruity or floral varietal characteristics. The quality of these wines is dependent on vintner practices that control oxygen levels during the winemaking and aging processes.Exposure to oxygen at any point in these processes is generally considered to have a negative impact on color, aroma, flavor and shelf-life. However, the process of hyperoxidation, the intentional exposure to high levels of oxygen to recently pressed juice, has been used to initiate enzymatically-controlled oxidation cascades that remove the phenolic precursors of oxidized compounds that negatively impact the color and flavor of the finished product. Removal of these precursors prior to vinification leads to a product that is more shelf-stable and less harsh or bitter in flavor. Storage temperatures can also affect the quality of white wine by modifying or decreasing terpene or ester contents and by forming new detrimental flavor constituents. The proposed research aims to critically evaluate the effects of hyperoxidation and temperature on ‘Riesling’ wines through chemical and sensory tests conducted throughout various stages of wine production. Future studies will compare the flavor profiles of other white wine varieties, optimize oxygen and sulfur dioxide levels, and explore consumer attitudes via focus groups. The successful delineation of optimized hyperoxidation treatments will potentially benefit the consumer and wineries alike. By creating a white wine that may have a longer shelf life, vintages can be sold for years.