Disclosed is a method of preparing a composition, comprising a micronized insoluble organic UV absorber, which method comprises grinding the insoluble organic UV absorber, in coarse particle form, in a grinding apparatus comprising yttrium-stabilized zirconium oxide grinding beads, in the presence of alkyl polyglucoside having the formula CnH2n+1O(C6H10O5)xH, in which n is an integer ranging from 8 to 16 and x is the mean polymerisation level of the glucoside moiety (C6H10O5) and ranges from 1.4 to 1.6, or an ester thereof and in the presence of an antifoam agent as dispersingagent auxiliary.