In the present article we describe the fermentation characteristics of some novel, natural yeast hybrids (S. cerevisiaexS. kudriavzevii), isolated from Austrian vineyards, and their significance for the aroma spectra of wines they produced. S. cerevisiae, S. bayanus var. uvarum and S. kudriavzevii were used for comparison. Fermentation took place at four different temperatures (14 degrees C, 18 degrees C, 22 degrees C and 26 degrees C) in two grape must varieties, Blauburger and Muskat Ottonell. The fermentation performed by the hybrids occurred more harmoniously than that carried out by the reference yeasts. At any temperature the fermentation rate was in the upper range, especially that of fructose fermentation. Furthermore, the production of ethanol was remarkable. The aroma compositions of wines created by hybrids resemble those of the parental species, but certain aroma constituents (depending on the must) are significantly more concentrated in the hybrid-produced wines. These novel criteria may be advantageous for wine making.