This test allows the quantitative detection of all species of Dekkera (Brettanomyces) and Saccharomyces cerevisiae var. diastaticus together in one screening test. 

Both yeasts belong to the superattenuating yeasts which are regarded as spoilers in conventional beers, although used in sour beer production. The taste of contaminated beer is unpleasant, sour and reminding of horse sweat for Brettanomyces, in case of S. cerevisiae var. diastaticus described as loss of body and dry mouthfeel. It often takes months until spoilage becomes obvious in finished products, but when not properly chilled, growth can occur suddenly after several weeks of silence. These yeasts metabolize long chain carbohydrates, producing carbon dioxide. If packaged units are infected, pressure can increase up to causing bottle or can explosion, posing a severe hazard to consumers.