A method for manufacturing a coloring agent for keratin fibers from a first composition A and a second composition B is provided. The method comprises directing the first composition A from a container A by a filler apparatus through an inlet opening into a second container B containing the second composition B. In container B, as a result of the introduction of composition A and/or the action of the filler apparatus, at least one exit opening is formed out of which the coloring agent for keratin fibers exits from container B as a mixture of compositions A and B.