  As part of the search for planets around evolved stars, we can understand
planet populations around significantly higher-mass stars than the Sun on the
main sequence. This population is difficult to study any other way,
particularly with radial-velocities since these stars are too hot and rotate
too fast to measure precise velocities. Here we estimate stellar parameters for
all of the giant stars from the EXPRESS project, which aims to detect planets
orbiting evolved stars, and study their occurrence rate as a function of
stellar mass. We analyse high resolution echelle spectra of these stars, and
compute the atmospheric parameters by measuring the equivalent widths for a set
of iron lines, using an updated method implemented during this work. Physical
parameters are computed by interpolating through a grid of stellar evolutionary
models, following a procedure that carefully takes into account the post-MS
evolutionary phases. Probabilities of the star being in the red giant branch
(RBG) or the horizontal branch (HB) are estimated from the derived
distributions. Results: We find that, out of 166 evolved stars, 101 of them are
most likely in the RGB phase, while 65 of them are in the HB phase. The mean
derived mass is 1.41 and 1.87 Msun for RGB and HB stars, respectively. To
validate our method, we compared our results with interferometry and
asteroseismology studies. We find a difference in the radius with
interferometry of 1.7%. With asteroseismology, we find 2.4% difference in logg,
1.5% in radius, 6.2% in mass, and 11.9% in age. Compared with previous
spectroscopic studies, and find a 0.5% difference in Teff, 1% in logg, and 2%
in [Fe/H]. We also find a mean mass difference with respect to the EXPRESS
original catalogue of 16%. We show that the method presented here can greatly
improve the estimates of the stellar parameters for giant stars compared to
what was presented previously.
