The article presents main methods of studying restored whey-malty mixtures after fermentation by lactose-fermenting yeast and saccharomyces for getting a beverage of the kvass type.The methods of accumulation of yeast cells Kluyveromyces lactis 469 and their percent with glycogen from the general concentration at fermentation of wort of the restored mixture at different ratios of dry malt and whey are offered and results are obtained. According to the obtained data, it was established, that yeast cells actively developed in the period from 4 to 16 fermentation hour at the ratio of malt and whey in the restored mixture as 1:1,5 and 1:2. The increment of cells with glycogen in mixtures with the ratio – malt:whey as 1,5:1 and 2:1 was intensive. Thus, at 36 hour of fermentation the amount of yeast was 67,2 and 68,9 % respectively from the total number of cells.The generative capacity of yeast allowed to specify the fermentation temperature of wort of restored mixtures, cultivated by different races. It was established, that for Kluyveromyces lactis 469 the maximal accumulation of yeast (67…69 mln cell/cm3 of wort) is observed at fermentation temperature – 30…32 °С, for Saccharomyces cerevisiae Р-87 and Saccharomyces cerevisiae M-5 – 30…34 °С.The gasochromatographic method allowed to identify side products of fermentation of fermented whey-malty wort by both lactose fermenting yeast and saccharomyces. The presented information is enough for the objective assessment of the qualitative composition of fermentation products as a result of the effect of different yeast races. The use of Saccharomyces cerevisiae Р-87 for fermentation of whey-malty wort positively influences metabolism of a producer, stimulating biosynthesis or transformation of aromatic substances of the nutritive medium. The obtained research results indicate objective possibilities for the effective functioning of the aforesaid yeast race for fermentation of restored whey-malty wort in production systems.