Silicone-containing defoamer for aqueous pigment concentrates for use in coatings, printing inks and overprint varnishes. Prevents foam during grinding. Long-term and shear stability. Particularly suitable for resin-free grinds (slurries). BYK-019 is particularly suitable for aqueous overprint varnishes based on acrylate dispersions, polyurethane dispersions and polyurethane/acrylate combinations and for defoaming pigment concentrates. To reduce microfoam, a combination of BYK-019 with BYK-024 in a ratio of 3:2 has proven successful in defoaming pigment concentrates.