Alcohol’s Influence on Sensory Development

 The impact of grape ripening has numerous significant chemical and sensorial aspects of wine. Seasonal variation, vineyard location, and grape variety all impact the extent of ripening, commonly referred to as “hang time,” that can occur. Within the past 10 years, the production of higher ethanol content wines from fruit that has undergone hang time has become more common. Little research has been done to evaluate the impacts of hang time on grapes and wine. In this presentation, the impacts of ripening and ethanol concentration on the wine chemical and sensory composition will be discussed in relation to Washington state Merlot, Syrah, and Cabernet Sauvignon grapes. In each experiment, fruit was picked at three different soluble solids (20, 24 & 28 Brix) over a 55 to 66-day period. Further in each experiment, the amount of ethanol produced was controlled by sugar addition (chaptalization) or juice removal and water addition (saignée-water back) prior to fermentation. The results of these experiments will be discussed with regard to how hang time and ethanol concentration influences sensorial aspects of wine and how color and tannin changes during ripening and wine aging.

Speaker Bios

Jim Harbertson, PhD, is an associate professor of enology at Washington State University’s Wine Science Center in Richland, Washington. He received his bachelor’s degree in biochemistry and doctorate in agricultural chemistry from the University of California, Davis. Jim’s research focuses on the phenolic compounds found in grapes and wine and their biochemical and chemical changes during grape ripening, winemaking and aging. Jim serves as an associate editor for the Australian Journal of Grape and Wine Research. Jim has been awarded Best Enology Paper from the American Journal of Enology and Viticulture three times (2010, 2014, 2017). Jim is an active volunteer for the American Society of Enology and Viticulture, serving in various capacities on the board and now serves as the president and the interim technical program director.
James Osborne is as an Associate Professor in the Food Science and Technology Department at Oregon State University. He received his PhD from Washington State University in 2005 researching interactions between wine yeast and malolactic bacteria after which he spent time in his native New Zealand working at the University of Auckland and Delegat’s Winery. His current research focuses on the impact of wine microorganisms such as lactic acid bacteria, Brettanomyces, and non-Saccharomyces yeast on wine quality. James is the statewide enology extension specialist for Oregon providing outreach programs for the Oregon wine industry. This includes the development of industry workshops and seminars to aid in the transfer of relevant research results to commercial application as well as technical workshops focused on various enology topics. In addition, James also teaches undergraduate and graduate classes in support of the enology and viticulture program at Oregon State University.

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