A system is provided. The system includes an electrosurgical generator configured to measure, collect and record data pertaining to a characteristic of tissue as the tissue is being electrosurgically treated. A tuner configured to couple to the electrosurgical generator includes a tuning circuit providing a load having a variable complex impedance for the electrosurgical generator when the electrosurgical generator is connected thereto. A controller including stored data pertaining to impedance values is in operable communication with the electrosurgical generator for retrieving the recorded data pertaining to the characteristic of tissue. The controller is in operable communication with the tuner for varying a complex impedance of the load. The controller configured to compare the recorded data pertaining to the at least one characteristic of tissue with the stored data pertaining to the plurality of impedance values and to adjust the tuner to one of the plurality of impedance values.