## 3 Results  
During the fermentation processes, the sugar content of the juice of ripe Vranec and Cabernet Sauvignon grapes was 247 g/L and 236 g/L, respectively. Titratable acidity (TA) was in the range of 6.7-7.1 g/L, while pH values for grapes from the Vranec and Cabernet Sauvignon grape variety were 3.54 and 3.40, respectively. Data were measured before fermentation and presented as mean values of two replicates from each harvested year (2016 and 2017, respectively) (Table 2). Dynamics of the Alcoholic Fermentation throughout Time to Produce Wines from Vranec and Cabernet Sauvignon Grape Varieties  
The autochthonous and commercial yeast strains, belonging to the species of _Saccharomyces cerevisiae_, clearly demonstrated different dynamics of alcoholic fermentation and different content of dry-matter for Vranec wines. As seen in Figure 1, the application of autochthonous yeast strain F-78 indicated a faster and sharper decrease in total sugar content in the wines from the Vranec grape variety, while application of commercial yeast D-80 led to a slower decrease of total sugars in the wines from the same grape variety. The differences in the shape of the curves for the three Vranec wines are especially noticeable from the fifth day to the eighth day of the alcoholic fermentation. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Grape Variety** & **Vintage Year** & **Sugar Content (g/L)** & **Titratable Acidity (TA) (g/L)** & **pH** \\ \hline Vranec & 2016 & 245 & 234 & 3.51 \\ Vranec & 2016 & 249 & 238 & 3.54 \\ Cabernet Sauvignon & 2017 & 246 & 235 & 3.41 \\ Cabernet Sauvignon & 2017 & 248 & 237 & 3.40 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Sugar content, titratable acidity, and pH values of grapes from Vranec and Cabernet Sauvignon for vintage years 2016 and 2017. At the end of alcoholic fermentation (16 th day), the amount of residual sugar was in the range of 2-3 g/L, thus leading to the production of dry-wines, while the percentage of alcohol was in the range of 13.97-14.68% (vol.). Moreover, the results depicted in Figure 1 indicate that likewise, the commercial yeast (D-80) and the autochthonous (F-8 and F-78) yeasts also finished the alcoholic fermentation with similar amounts of total residual sugars. The dynamics of the alcoholic fermentation of wines produced from the Cabernet Sauvignon grape variety by application of the same yeast strains (F-8, F-78, and D-80) are illustrated in Figure 2.  
Figure 1: Dynamics of alcoholic fermentation of Vranec wines produced by autochthonous and commercial yeast strains, obtained by screening of the total amount of reducing sugars. The results refer to the mean values and standard deviations (mean \(\pm\) STDV), expressed as g/L. Mean \(\pm\) STDV were calculated from one replicate of each fermentation type (see Table 1) and four analytical measurements. Wine type abbreviations are defined in Table 1.  
Figure 2: Dynamics of the alcoholic fermentation of Cabernet Sauvignon wines produced by autochthonous and commercial yeast strains through the screening of the total amount of reducing sugars. The results refer to the mean values and standard deviations (mean \(\pm\) STDV), expressed as g/L. Mean \(\pm\) STDV were calculated from one replicate of each fermentation type (see Table 1) and four analytical measurements. Wine type abbreviations are defined in Table 1.  
As seen in Figure 2, the shapes of the curves were slightly different in comparison to Vranec wines (Figure 1). The decrease of the sugar content in the Cabernet Sauvignon wine fermented by F-78 (wine CS2) was smoother while wines CS1 and CS3 (wines fermented with F-8 and D-80, respectively) had similar shape of curves with a sharper decrease in total sugar content from the 9 th to 11 th days of fermentation when compared to the previous days of fermentation.