An electrosurgical generator is disclosed. The generator includes a radio frequency output stage configured to generate a frequency waveform to an active electrode of an electrosurgical instrument when the active electrode is disposed in a fluid medium. The generator also includes a sensor circuit configured to measure tissue impedance and a controller configured to increase power of the radio frequency waveform to a predetermined electrical arcing level in response to the tissue impedance being within an open circuit impedance range and tissue contact impedance range. The controller is further configured to lower the power of the radio frequency waveform to a lower level when the tissue impedance is outside the open circuit impedance range and the tissue contact impedance range.