A foam-inhibiting aqueous concentrate, stable in alkaline compositions, contains(a) about 5 to about 30% by weight of alkyl glucoside based on C.sub.6 -C.sub.12 fatty alcohols having a degree of glucosidation of about 1 to about 2,(b) about 5 to about 70% by weight of end-capped polyethylene glycol ether compound corresponding to formula IR.sub.1 O--(CH.sub.2 CH.sub.2 O).sub.n --R.sub.2 (I) wherein the radical R.sub.1 O is derived from 2-branched, even-numbered alkanols containing from 16 to 20 carbon atoms, R.sub.2 is an alkyl radical containing 4 to 8 carbon atoms, and n is a number of about 5 to about 9,(c) about 5 to about 70% by weight of non-end-capped polyethylene glycol ether compound corresponding to formula IIR.sub.5 O--(CH.sub.2 CH.sub.2 O).sub.2 --H (II) wherein the radical R.sub.5 O is derived from 2-branched even-numbered alkanols containing from 12 to 20 carbon atoms, and z is a number of about 2 to about 5.