This paper describes an improvement of a method for continuous calibration of the global heat transfer coefficient, recently described in literature [A. Tietze, Moglichkeiten und Grenzen der Temperaturschwingungskalorimetrie, Doctoral Thesis, Technishe Universitat Berlin, 1998; Chem. Eng. Sci. 51 (1996) 3131; Chem. Ing. Tech. 68 (1996) 97]. The continuous calibration method is based on induced sinusoidal jacket temperature oscillations, allowing the uncoupling of the chemical heat production from the heat transfer parameters during the reaction. A mathematical computation procedure based on two-anchors, before and after the reaction, has been developed which gives better results as compared to the one reported in literature, using one-anchor only, either before or after the reaction. The applicability of this method to biotechnology has been explored with respect to different culture parameters, which affect the global heat transfer coefficient, i.e. stirring speed, reactive volume, and medium viscosity. This oscillating reaction calorimetry method (ORC) has been successfully applied to a fed-batch culture of Saccharomyces cerevisiae with a non-linear increase of reactive volume. (C) 2001 Elsevier Science B.V. All rights reserved.