## 1 Introduction  
The quality and style of the wine are primarily determined by the place where the vine grows. The most important factors at each location are the soil and the climatic conditions [1, 2]. Many variables, such as the total soluble solids content, total titratable acidity, nitrogen content, and balance of phenolic compounds in grapes and wines, are therefore influenced by genetic (varietal) and environmental factors, known as terror, and by the vintage [3]. Merlot grown in cool climates or with low sun exposure may be green due to the presence of 2-isobutyl-3-methoxypyrazine (IBMP), although this is rare in Merlot as it tends to ripen early. Merlot grown in temperate climates expresses fruity aromas and develops a complex ageing bouquet after a few years of bottle ageing. These positive characteristics are caused by a wide range of compounds, including substituted esters, varietal thiols (especially 3-mercaptoethanol-1-ol (3 MH)) and dimethyl sulphide (DMS) [2]. It has long been known through sensory evaluation that the taste of a wine from a particular variety can be associated with its origin and that wine typicity in relation to terror is also largely shaped by aroma compounds [2]. However, the comparison between the sensory representations of wine as a concept and the descriptive methods revealed a gap between the conceptual and perceptual representation of typicality. On the one hand, the conceptual representation was consistent with soil as the first factor influencing typicity. On the other hand, the perceptual representation lacked consensus and emphasised the predominance of technical factors, particularly oenological factors, over environmental factors [4]. The management of microbial activity during winemaking is certainly one of the most important technical factors, as many wine aroma compounds are either undetectable or present as odourless bound precursors in the grapes formed during the alcoholic fermentation process. The microbiota of grapes and wine exhibits regionally defined patterns related to the vineyard and climatic conditions [5; 6], but for a long time, it was not entirely clear to what extent these microbial patterns were related to the chemical composition (volatile compounds--VOCs) of the wine [6; 7]. Recent studies provided new insights into the metabolic pathways of key flavour compounds formed by indigenous microorganisms during spontaneous alcoholic fermentation [8; 9]. Traditional winemaking practices either encourage or rely entirely on fermentations with non-inoculated microorganisms. This practice is seen by its adherents as enhancing regional typicity [7] and could differentiate wine estates [9]. The microbiota and metabolites of grape and wine differ geographically, with several layers of fungal and bacteria microbiota identified that correlate with wine aroma profiles [6; 8; 9], and it has been shown that characteristic _S. cerevisiae_ exert the strongest influences on wine quality and style at small geographic scales [10]. However, it was pointed out that experimental research is still needed to investigate the contribution of this assembly of microorganisms to the final product and to support or refute the concept of microbial terror [11]. In uninoculated alcoholic fermentations (spontaneous alcoholic fermentations), there is a progressive growth pattern of indigenous yeasts, with the final stages invariably dominated by the Crabtree-positive, alcohol-tolerant strains of _S. cerevisiae_[12]. Of the indigenous yeasts other than _Saccharomyces_, _Hanseniuspora_ spp. and _Sarmerella_/_Candida_ spp. are most prevalent in the early stages of many spontaneous alcoholic fermentations [8; 9; 13; 14; 15; 16]. The _Hanseniuspora_ spp. most commonly found on grapes and most associated with alcoholic fermentation are _H. vineae_[17], _H. osmophila_[18] and _H. urarum_[19].