Abstract: This invention relates to a method for determining the absolute temperature of a substance, comprising the steps of: sensing the absolute temperature of the substance and generating an absolute value associated therewith; sensing a temperature difference between the temperature of a reference body and the temperature of the substance and generating a difference value associated therewith; determining an optimised value of the absolute temperature of the substance by means of said absolute value and said difference value. The invention also relates to an apparatus for performing the method; a temperature control system for controlling the temperature of a substance; and an instrument comprising a substance, and such a temperature control system.