Anotace:
Knowledge of yeast concentration is necessary for the pitching rate estimation. Centrifugation and turbidimetric method present rapid and easy methods for the determination of yeast concentration. There are many variants of such techniques to monitor laboratory fermentations even in test tube sizes. Procedures with and without sodium hydroxide solution were compared and evaluated. A simple calculation procedure is based on two parameters, which have to be determined for the local condition of each brewery. They cover yeast dry matter content of yeast sample and the yeast count related to 1 g completely dry yeast. It enables to calculate the probable cell count in pitched substrate, which can be used for the photometric calibration curve construction. Linear and logarithmic relation was used to express relation between yeast concentration and absorbance at 800 nm. The method based on yeast deflocculation enabled to estimate starting yeast activity.