A flow cytometric method based on staining with fluorescein diacetate (FDA) for rapid measurement of the fluorescence intensity (FI) of individual brewing yeast cells is reported. Distinct changes in the FI of yeast populations during the course of both laboratory scale and brewery fermentations were observed. The changes followed a characteristic pattern defined as the FI‐profile. The FI‐profile was related to the rate of attenuation as well as changes in yeast glycogen and ergosterol contents. The results obtained suggest that flow cytometry can be applied for estimation of intracellular events in brewing yeasts and prediction of their performance. 1994 The Institute of Brewing & Distilling