An ultrasonic surgical instrument comprising an ultrasonic electromechanical system comprising an ultrasonic transducer coupled to an ultrasonic blade via an ultrasonic waveguide and a generator configured to supply power to the ultrasonic transducer, wherein the generator comprises a control circuit configured to measure a resonant frequency of an ultrasonic blade prior to activating an ultrasonic transducer, wherein the ultrasonic transducer is coupled to the ultrasonic blade via an ultrasonic waveguide； compare the measured resonant frequency to a baseline resonant frequency； determine an initial temperature of the ultrasonic blade based on a difference between the measured resonant frequency and the baseline resonant frequency； and apply a power level to the ultrasonic blade based on the initial temperature of the ultrasonic blade. The control circuit may be further configured to apply a high power level to the ultrasonic transducer to increase a temperature of the ultrasonic blade when the initial temperature of the ultrasonic blade is low. The control circuit may be further configured to store the baseline resonant frequency in a memory look up table, and retrieve the baseline resonant frequency from the memory look up table.
