Yeast Classification*

Following a discussion of the need for systems of classification, which are inevitably to some extent subjective, a survey is made of primary and auxiliary diagnostic tests used in yeast classification. The possibilities and limitations of numerical taxonomy are discussed and an assessment is made of the value of current techniques used for identifying strains of brewing yeasts. Methods are described for detecting wild yeasts and for evaluating the suitability of different strains of brewing yeast. Reasons are given for retaining Saccharomyces carlsbergensis as a species in its own right rather than as a synonym of Sacch. uvarum.