  We offer a diagrammatic derivation of the effective masses of the axial
flavor excitations in the electrical and color neutral CFL phase of QCD. In
particular we concentrate on the excitations with the quantum numbers of the
kaons: we show how their effective chemical potentials, responsible of their
Bose-Einstein condensation and found previously on the basis of pure symmetry
arguments, arise at the microscopic level by loop effects. We perform also the
numerical evaluation of the relevant loops in the whole CFL regime
$M_s^2/2\mu\Delta\leqslant 1$, showing the existence of the enhancement of the
kaon condensation with respect to the lowest order result. Finally we discuss
the role of electrical and color neutrality in the microscopic calculation.
