STUDIES OF SOME YEASTS CAUSING SPOILAGE OF DRAUGHT BEERS*

Abstract

Yeasts other than Saccharomyces carlsbergensis, isolated from turbid draught beers, have now been examined. Strains of S. cerevisiae including three well defined strains of S. cerevisiae var. turbidans have been found in the various spoiled beers, and, in addition, Kloeckera brevis, Candida krusel, C. lipolytica, Mycoderma cerevisiae, Pichia belgica and P. alcoboiophila. The distribution of these organisms and their effect on beer is examined. Strains of S. carlsbergensis, S. cerevisiae var. turbidans and K. brevis grow rapidly in beer with the formation of a haze not removable by finings. The remaining species are largely of a film-forming nature but sometimes contribute to the general haziness, particularly Candida krusei which can grow by fermentative dissimilation of glucose and which (in the case of one strain) does not give satisfactory flocculation with finings.