THE USE OF GIANT‐COLONY MORPHOLOGY FOR THE DIFFERENTIATION OF BREWING YEASTS

Abstract

A simple, reproducible dilution/plating procedure is described for the production of giant‐colonies of yeasts. The simplicity of the technique is such that the operator time necessary to perform the analysis is similar to that required by the Gilliland procedure and is less than one‐quarter of the time required by the Hough method. Furthermore, the discrimination afforded by observation of giant‐colony morphology exceeds even that of the Hough procedure. The problem of describing the morphological details of the giant‐colonies has been partially solved by the recognition of 6 basic types of morphology. An incubation period of 10 days at 22° C, results in satisfactory giant‐colonies with some yeast strains, but with others a 3–4 week incubation at 18° C. is preferable. 1967 The Institute of Brewing & Distilling