  The temperature evolution of the chiral condensates in a gas made of pions,
kaons and etas is studied within the framework of SU(2) and SU(3) Chiral
Perturbation Theory. We describe the temperature dependence of the quark
condensates by using the meson meson scattering phase shifts in a second order
virial expansion. We find that the SU(3) formalism yields an extrapolated
melting temperature for the non-strange condensates which is lower by about
20-30 MeV than within SU(2). In addition our results show that the strange
condensate melting is slower than that of the non-strange, due to the different
strange and non-strange quark masses.
