A system for preparing a medicament for use by a medicament user includes a proportioning machine with a controller and pumping and clamping actuators to engage a fluid circuit having pumping and clamping portions that engage with respective actuators of the proportioning machine. The fluid circuit includes a mixing container that is initially empty and later filled with two different concentrated medicaments from different concentrate containers and with purified water. The proportioning machine is configured to receive purified water and to mix it with the concentrated medicaments to produce a medicament and to output the medicament to a medicament consumer in such a way that to the medicament consumer the medicament appears to be provided from a bag of medicament. Custom mini batches of medicament may be produced by varying the amount of the concentrates and water.