Danielle Fox and James Harbertson*
*Washington State University, 2710 Crimson Way, Richland, WA, 99354-1671 (jfharbertson@wsu.edu)

Cabernet Sauvignon grapes were harvested at three potential alcohols (11, 13.5, and 16% v/v, ABV) from a vineyard in Sunnyside, Washington in 2018 and 2019.  Alcohol was controlled for pre-fermentation by either dilution or chaptalization. At each harvest, the 13.5 and 16.0% ABV wines were dealcoholized to 11 and 13.5% ABV using a pilot-scale dealcoholization (DA). The initial experimental alcohol was treated as the control, the dealcoholized wine the treatment, and the wine sharing the same alcohol target and harvest date as the dealcoholized wine was designated as the negative control. Basic wine chemistry was determined and untargeted solid-phase microextraction gas chromatography-mass spectrometry was used to identify major aroma compounds present. Targeted analysis was performed on various classes of wine aromatics (alcohols, esters, aldehydes, terpenes, pyrazines) informed by the untargeted analysis. Descriptive analysis was performed on the 2019 wines by nine panelists (four males). Three taste, three mouthfeel, five ortho-, and seven retro-nasal aroma attributes were significant. DA had no significant affect on any basic wine chemistry other than the intended alcohol. For all aroma compound classes measured, the negative control and dealcoholized treatments were significantly lower in concentration than the higher ABV controls. Similarly, the retro- and ortho-nasal aroma attributes were rated lower intensity in the negative control and DA treatments than in the higher ABV controls. Generally, the experiment shows that dealcoholization is not absorbing or “scalping” aroma compounds. Instead, the reduction of aroma compounds is due to volatile compound partitioning effects that are directly influenced by ethanol concentration. These results show that wine aromas, and thus wine styles, may be manipulated postfermentation by dealcoholization.

Funding Support: Washington Wine Commission