## 1 Introduction  
Nowadays, selected pure cultures of wine yeasts are mainly used in winemaking, which has led to a significant improvement in wine technology and respective final quality, because of multiple benefits such as the ability to undertake a quick and effective fermentation of grape juice or must with high sugar concentration; resistibility to high levels of ethanol (C\({}_{2}\)H\({}_{6}\)O) and sulfur dioxide (SO\({}_{2}\)); and resistance to high temperatures during fermentation [1]. Indeed, the increasing usage of traded selected yeasts for winemaking leads inevitably to a loss of the autochthonous yeast populations naturally present in regional grapes and, consequently, drives to the potential loss of genetic diversity and heritage. Largely, the specificities, authenticity, uniqueness and, most importantly, the quality characteristics of the wine are dependent on the natural microbiota found in the grapes of each viticulture region [2] and, of course, the quality of the grapes by itself, which deeply depends on the soil and climate conditions of the geographic region and the employed viticulture techniques, which also determine per se the type of microbiota present therein. Over the last few years, increasing interest among scientists and winemakers has been observed in exploiting autochthonous yeast strains. After isolation and the selection of yeast strains with good phenotype and technological characteristics, they can be further employed in winemaking processes with high potential to be successful. Such a trend can be very important toward ameliorating the microbial biodiversity in the selected region and contributing to enriching the biological heritage, which is of great importance, in a highly competitive market, for the winery industry chasing for wine appellation and production of wines with unique/differentiated flavors and aromas [3]. Comparison of the main communities of cultivable yeast species and strains between two different neighboring _Vitis_ ecosystems suggested that specific (yet unknown) characteristics of different symbiotic _Vitis_ species may contribute to the assembly of specific communities of biologically compatible yeast strains from a given number of species. In turn, the growth dynamics of these yeast populations during spontaneous fermentation can be translated into specific organoleptic and sensory traits of the final wines, depending on each variety of grape [4]. In addition, the microbial dynamics of alcoholic fermentation significantly affect the extraction of anthocyanins from grape skins and tannins from grape seeds, which will further influence, in cascade, the overall bitterness and astringency of the red wines [5]. Moreover, different maceration techniques, namely enzyme treatment, cold-soaking, and post-maceration as well as the combination of cold with post-maceration, influence the extraction process and the subsequent level of anthocyanins and tannins in wines [6]. The environment of wine fermentation has a great impact on the extraction and retention of tannins and other phenolic compounds from the red grape skins and seeds [7; 8]. An adequate selection of the indigenous and commercial yeast strains combined with the use of enological tannins containing a mixture of phenolic compounds was employed to drive the transformation of the grape anthocyanins into certain derivatives, some of which are more stable from a chemical standpoint [9; 10]. On the other hand, anthocyanins are the main compounds present in young red wines, being responsible for their intense red color. These pigments are mainly located in the grape skins and their extractability during winemaking depends on many factors such as their concentration in cell vacuoles and their interaction with the cell-wall polysaccharides, thus further affecting their stability and concentration in the must [11].