  The instanton interaction in QCD generates an effective potential for scalar
quark-antiquark condensates in the color singlet and octet channels. For three
light quark flavors the cubic term in this potential induces an octet
condensate and ``spontaneous breaking'' of color in the vacuum. Realistic
masses of the rho- and eta'-mesons are compatible with
renormalization-group-improved instanton perturbation theory.
