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58 p r a c t i c a l w i n e r y & v i n e ya r d O c t O B e r 2 0 1 4 w i n e M A K i n G Allison K. Baker and Carolyn F. Ross, School of Food Science, Washington State University, Pullman Wash. BY Impact of wine matrix on red wine finish and consumer acceptance T E C H N I C A L R E S O U R C E F O R G R O W E R S & W I N E R I E S 61 How extraction of oak volatiles and ellagitannin compounds affect sensory profile of wine aged with French winewoods By Kleopatra Chira and Pierre-Louis Teissedre 67 Bosché Vineyard sustains grape and wine quality By Liz Thach practicalwinerylibrary.com Access Practical Winery & Vineyard article archives online. Specifically, tannin and ethanol have been shown to contribute to the percep- tion of aroma and flavor in red wine, impacting the volatility and intensity of certain aroma compounds. 5,7,8,11 Thus, to investigate the role of wine finish on wine quality and impact of the wine matrix components on wine finish, a study was conducted using experi- enced wine consumers. These consum- ers evaluated a commercial Syrah adjusted to varying tannin and ethanol levels. The low ethanol treatment was 9% alcohol, and the high was 14% alco- hol. Each treatment was also adjusted to a high and a low tannin concentration using grape extracted tannins to create a total of four wine matrix treatments falling within the concentrations typical of red wines. These wine matrix treatments were spiked with one of three flavors of inter- est (2-phenylethanol [floral]), 3-isobutyl- 2-methoxypyrazine [bell pepper] and oak lactone [coconut]). Consumers evalu- ated the duration of finish in each of these samples using a digital timer and then responded to questions regarding the intensity of the finish and their accep- tance of that finish. The impact of the wine matrix on fla- vor finish duration indicated that there was no interaction between the tannin and ethanol levels themselves and that, overall, ethanol had a more dramatic impact on the duration of finish as com- pared to the influence of tannin level (Figure 1). For all three flavors investigated, con- sumers found the high ethanol samples to have a longer duration of finish (mea- sured in seconds). In particular, high- ethanol samples spiked with floral, coco- nut and bell pepper finished on average 12.4 seconds, 6.8 seconds and 7.7 seconds later, respectively, than the low-ethanol counterparts. These results support previous studies that found increased ethanol concentra- tion, which increases the solubility of most flavor molecules in wine, resulted in a reduced concentration of flavor vola- tiles in the headspace, decreased aroma intensity and increased flavor intensity. 7,9 Tannin concentration only signifi- cantly impacted bell pepper finish, resulting in a finish that was 5.6 seconds longer in the high-tannin treatments compared to their low-tannin counter- parts. A similar interaction between pyrazines and molecules with phenolic rings was observed by J. Aronson and S.E. Ebeler. 1 With more tannin (more phenol rings), the pyrazine molecule responsible for the bell pepper finish is held in solution due to this interaction, resulting in a longer bell pepper finish. To ensure that consumers were evalu- ating the flavor finish as intended, par- ticipants were asked to indicate which W hat makes a quality glass of wine? This question has no sin- gle or simple answer. Common conceptions of what com- prises a "good wine" include nebu- lous terms such as "balanced" and often incorporate the appearance attributes of the wine (color and clarity) and its aroma, flavor and mouthfeel. Economic studies have sought to answer this question and include "wine finish" (the lingering taste and flavor after swallowing or expectorating wine) 4 as a factor influencing wine quality. 2,6 Wine finish remains an understudied area of research, but it is closely related to the well-studied attributes of wine aroma and flavor. It is important to note that wine is composed of much more than just the volatile compounds themselves. These other wine compo- nents include sugars, acids, ethanol and tannin and are termed "wine matrix components." The authors thank The Rhone Rangers for support in conducting the research. Don Neel, Editor