Both the taste and aroma of cachaça, an alcoholic beverage produced by yeast fermentation of sugar cane, are influenced by yeast metabolites and volatiles. The knowledge of yeast population dynamics during the fermentation process will help to establish the basis for quality control of alcoholic beverage. In the present work, the population dynamics of three fermentation processes, with differing levels of technological sophistication, were studied. Saccharomyces cerevisiae was found to be the dominant species, but Candida milleri (Candida humilis), Pichia caribbica, Pichia guilliermondii and Zygosaccharomyces fermentati (Lachancea fermentati) were also significantly involved. In addition, four new yeast species that are not represented in NCBI/EMBL nucleotide database were found. These yeasts were classified as Candida sp., Candida drosophilae-like, Candida ubatubensis-like and Zygosaccharomyces sp. In fermentation trails at laboratory scale, all species were found to contribute to the production of volatiles. Thus it is probable that product quality is strongly dependent on population dynamics during the fermentation process.