# Bottle Aging Affected Aromatic and Phenolic Wine Composition More than Yeast Starter Strains
## 3 Results and Discussion
### Wine Aromatic Composition  
Figure 3 shows the results of the volatile composition of the wines made using the four yeasts at the end of MLF and after 6 and 9 months of aging in bottles. The content of total alcohols in the wines increased during the first 6 months in a bottle, remaining constant until the end of the studied period when Sc1 and Sc3 yeasts were used, while a marked decrease in their concentration was observed between 6 and 9 months in a bottle when the wines were made with Sc2 yeast. However, when Sc4 yeast was used, the content of total alcohols did not change (Figure 3a). [PERSON] and [PERSON] [18] observed that total alcohols increased as the wines remained in bottles for 6 months. The concentration of total alcohols after MLF was higher in wines made with Sc2 and Sc4 yeasts than when Sc1 and Sc3 yeasts were inoculated. Among the factors that affect the formation of alcohols in the fermentation, yeast strain is one of the main parameters [1; 26]. However, due to the different evolution of these compounds during aging, after 6 and 9 months in a bottle, it was the wines made with Sc2 and Sc3 yeast, respectively, that showed higher levels of total alcohols (Figure 3a). These compounds contribute to the aromatic complexity of the wines if the level is below 300 mg/L [27], a concentration not exceeded in any of the wines produced nor at any of the times studied (Figure 3a). Regarding esters, which are the most important fermentative compounds for the aromatic quality of wines, since they present low perception thresholds, contributing fruity and floral aromas to wines [6; 7], their evolution is shown in Figure 3b-e. As discussed for alcohols, their formation during fermentation depends on the yeast strain [28; 29]. The concentration of total acetate esters was not modified throughout the period studied when the wines were made with Sc1 and Sc4 yeasts, whereas their content decreased between 6 and 9 months of bottle aging for wines made with Sc2 and Sc3 yeasts (Figure 3b). Regardless of the aging time, the wines made with Sc4 yeast had the lowest concentration of total acetate esters, showing no significant differences between the other wines, Sc1-Sc3 (Figure 3b). The content of total C6, C8 and C10 ethyl esters remained unchanged during bottle aging for wines made with Sc3 yeast, but decreased when the other three yeasts, Sc1, Sc2 and Sc4, were used, with this decrease especially marked for wines made with Sc2 yeast (Figure 3c). Wines made with Sc4 yeast showed lower concentrations of these compounds, as described for total acetate esters, while the highest concentrations of total C6, C8 and C10 ethyl esters were found in Sc2 wines at the end of MLF, Sc1 after 6 months in bottles, and Sc1 and Sc3 after 9 months of aging (Figure 3c). Both the concentration and the evolution of total ethyl esters and total esters during the aging of the wines in a bottle were similar (Figure 3d,e), so they will be discussed together. It is worth noting the large increase in their content during the first 6 months in a bottle of the wines made with Sc1 yeast. The rest of the wines also showed this trend, so that their concentration increased in the first 6 months and then remained constant until the end of the studied period, except for the wines made with Sc2 yeast, for which the content of total ethyl esters and total esters decreased (Figure 3d,e). Logically, due to the large increase in the content of these esters in the wines made with Sc1, their concentration was higher in these wines than in the wines made with Sc2-Sc4 yeasts, which showed no significant differences between them (Figure 3d,e). The equilibrium concentrations of each ester and their hydrolysis products were different. The ethyl esters of fatty acids and the acetate esters of higher alcohols were hydrolyzed with the time of aging, whereas the ethyl esters of organic acids were formed during the storage of the wines in bottles [6,19].