We demonstrate a new procedure to derive accurate and precise surface gravities from high resolution spectra without the use of external constraints .
Our analysis utilizes Spectroscopy Made Easy ( SME ) with robust spectral line constraints and uses an iterative process to mitigate degeneracies in the fitting process .
We adopt an updated radiative transfer code , a new treatment for neutral perturber broadening , a line list with multiple gravity constraints and separate fitting for global stellar properties and abundance determinations .
To investigate the sources of temperature dependent trends in determining \log g noted in previous studies , we obtained Keck HIRES spectra of 42 Kepler asteroseismic stars .
In comparison to asteroseismically determined \log g our spectroscopic analysis has a constant offset of 0.01 dex with a root mean square ( RMS ) scatter of 0.05 dex .
We also analyzed 30 spectra which had published surface gravities determined using the a / R _ { * } technique from planetary transits and found a constant offset of 0.06 dex and RMS scatter of 0.07 dex .
The two samples covered effective temperatures between 5000K and 6700K with \log g between 3.7 and 4.6 .