## 2 Results and Discussion
### Orthonasal Aroma Attributes
First, even though panelists did detect the burn of ethanol in all the wines, they did so at a moderate level (based upon an average rating of 6.5 sensory units over 15). Second, it is possible that through cross-modal association [63] panelists might have ascribed red fruit and tropical fruit aromas to heat which is otherwise a character sometimes associated with Grenache wines from Mediterranean climates. Third, and most likely, the perception of the hot aroma could have been caused by the volatile compound 1-hexanol. 1-hexanol is a C6 alcohol attributed with herbaceous and resinous aroma characteristics [64]. 1-hexanol showed extremely high OAV values, of three orders of magnitude, in all wines indicating the compound had high sensory relevance (Table 3). In the two-way ANOVA, 1-hexanol (\(p\) = \(<\)0.0001) was significantly higher in PD wines compared to No PD wines (Supplemental Table S3). As well, 1-hexanol and the hot aroma were closely related in the PLSR (Figure 2). This aligns with the results of the previous literature, whereby the volatile and phenolic chemistry  
Figure 2: Partial least square regression analysis of volatile chemistry and sensory attributes. (**A**) Wine treatments (\(\blacksquare\)). (**B**) Correlation loading of the relationship between the volatile chemistry (\(\bullet\)) and sensory attributes (\(\blacktriangle\)). O: indicates orthonasal aroma; R: indicates retronasal aroma; V\({}_{\text{max}}\): maximum citation proportion; T\({}_{\text{max}}\): time of maximum citation proportion; AUC: area under the curve, total intensity response. impact of a floating cap treatment compared to submerged cap treatment in Barbera wines were examined [65]. Results indicated the floating cap treatments combined with pump covers had a significantly higher concentration of hexanol than the submerged cap wines, which was thought to be due to enzymatic oxidation. The only aroma attribute influenced by fermentation temperature was white pepper which was higher in the Cold and Cold/Hot wines. However, intensity ratings of white pepper aroma were low, ranging from 2.80 to 3.51 in scores on a 15 cm line scale (Table 1), so this specific attribute was unlikely to have a strong sensory impact. All the wines were similar in overall aroma intensity as well as red fruit, and tropical fruit aromas regardless of treatment. An explanation for the overall lack of differences seen with aroma intensities between the wines may have been due to a masking effect caused by reduction aromas and their associated chemical compounds. Two compounds responsible for reduction aromas in wines are hydrogen sulfide and methanethiol [46]. A previous study examined the aromatic impact of these two compounds as well as their interaction in model white, red, and red oak wines based on typical Spanish wines [66]. Wines were evaluated by a sensory method known as Rate-All-That-Apply (RATA). The results indicated that the presence of hydrogen sulfide and methanethiol significantly repressed fruit and floral aromas in the white and red wines. Based on these findings, it is likely that a similar masking effect occurred with the Grenae wines of the present study particularly as the aroma descriptors included attributes like rose, tropical fruit, and red fruit. However, the volatile chemistry results showed differences among the wines even if they may have not been perceived from a sensory perspective. Indeed, Cold wines had high concentrations of \(\beta\)-damascenone and Cold/Hot wines tended to have higher concentrations of the esters ethyl butyrate, isoamyl acetate, ethyl octanoate, and ethyl hexanoate (Table 3). Hot wines also had high concentrations of isoamyl acetate (Table 3). All of these compounds with high OAVs are associated with fruit aromas and therefore they were likely masked by reduction aromas.