Yeasts are the most significant microorganisms in all conversion steps of the grape/must/wine system. Because of their metabolic activity, yeasts play a central role in the must fermentation process and also in contamination and spoilage of the final products—wines. Consequently, only reliable and rapid identification of yeast species during process and quality control enables enologists to assess the role of yeasts as a main protagonist of alcoholic fermentation or as a contaminant.