Antifoam powder with delayed antifoam effect, comprising 5 to 35% by weight of an antifoam agent, which is a modified, aminofunctional organopolysiloxane consisting of at least one siloxane unit of the formula R 1 a Q b SiO 4 − a + b 2 and siloxane units of the formula R 1 c SiO 4 − c 2 where R 1 is identical or different and is a hydrogen atom, a monovalent, optionally fluorine-, chlorine- or bromine-atom-substituted C 1 - to C 18 -hydrocarbon radical or a C 1 - to C 12 -alkoxy radical or a hydroxy radical, Q is identical or different and is a modified or unmodified amino radical of the formula -R 2 -[NR 3 -(CH 2)m -] x NR 4 R 5 or forms thereof partially or completely protonated on the nitrogen atoms, where R 2 is a divalent C 1 -C 18 -hydrocarbon radical, R 3 is a hydrogen atom, a C 1 -C 10 -alkyl radical or a radical G of the formula -C(=O)-O-R 6, R 4 is a hydrogen atom, a C 1 -C 10 -alkyl radical or a radical G of the formula, R 5 is a hydrogen atom, a C 1 -C 10 -alkyl radical or a radical G of the formula, R 6 is a monovalent hydrocarbon radical having 1 to 18 carbon atoms which is unsubstituted or is substituted with one or two hydroxy groups, with the proviso that at least one radical Q has at least one radical G of the formula, a is 0, 1 or 2, b is 1, 2 or 3, c is 0, 1, 2 or 3, m is 2, 3 or 4 and x is 0, 1 or 2, and the sum a+b is less than or equal to 3, and 65 to 95% by weight of a carrier material selected from the group of sodium carbonate, sodium sulfate, aluminium silicate, potassium carbonate, potassium sulfate, sodium hydrogen carbonate, potassium hydrogen carbonate, zeolites, porous copolymer of urea or melamine or mixtures thereof with an alkanal and mixtures thereof. 5 to 35% by weight of an antifoam agent, which is a modified, aminofunctional organopolysiloxane consisting of at least one siloxane unit of the formula R 1 a Q b SiO 4 − a + b 2 and siloxane units of the formula R 1 c SiO 4 − c 2 where R 1 is identical or different and is a hydrogen atom, a monovalent, optionally fluorine-, chlorine- or bromine-atom-substituted C 1 - to C 18 -hydrocarbon radical or a C 1 - to C 12 -alkoxy radical or a hydroxy radical, Q is identical or different and is a modified or unmodified amino radical of the formula -R 2 -[NR 3 -(CH 2)m -] x NR 4 R 5 or forms thereof partially or completely protonated on the nitrogen atoms, where R 2 is a divalent C 1 -C 18 -hydrocarbon radical, R 3 is a hydrogen atom, a C 1 -C 10 -alkyl radical or a radical G of the formula -C(=O)-O-R 6, R 4 is a hydrogen atom, a C 1 -C 10 -alkyl radical or a radical G of the formula, R 5 is a hydrogen atom, a C 1 -C 10 -alkyl radical or a radical G of the formula, R 6 is a monovalent hydrocarbon radical having 1 to 18 carbon atoms which is unsubstituted or is substituted with one or two hydroxy groups, with the proviso that at least one radical Q has at least one radical G of the formula, a is 0, 1 or 2, b is 1, 2 or 3, c is 0, 1, 2 or 3, m is 2, 3 or 4 and x is 0, 1 or 2, and the sum a+b is less than or equal to 3, and R 1 is identical or different and is a hydrogen atom, a monovalent, optionally fluorine-, chlorine- or bromine-atom-substituted C 1 - to C 18 -hydrocarbon radical or a C 1 - to C 12 -alkoxy radical or a hydroxy radical, Q is identical or different and is a modified or unmodified amino radical of the formula -R 2 -[NR 3 -(CH 2)m -] x NR 4 R 5 or forms thereof partially or completely protonated on the nitrogen atoms, where R 2 is a divalent C 1 -C 18 -hydrocarbon radical, R 3 is a hydrogen atom, a C 1 -C 10 -alkyl radical or a radical G of the formula -C(=O)-O-R 6, R 4 is a hydrogen atom, a C 1 -C 10 -alkyl radical or a radical G of the formula, R 5 is a hydrogen atom, a C 1 -C 10 -alkyl radical or a radical G of the formula, R 6 is a monovalent hydrocarbon radical having 1 to 18 carbon atoms which is unsubstituted or is substituted with one or two hydroxy groups, with the proviso that at least one radical Q has at least one radical G of the formula, a is 0, 1 or 2, b is 1, 2 or 3, c is 0, 1, 2 or 3, m is 2, 3 or 4 and x is 0, 1 or 2, and the sum a+b is less than or equal to 3, and 65 to 95% by weight of a carrier material selected from the group of sodium carbonate, sodium sulfate, aluminium silicate, potassium carbonate, potassium sulfate, sodium hydrogen carbonate, potassium hydrogen carbonate, zeolites, porous copolymer of urea or melamine or mixtures thereof with an alkanal and mixtures thereof.