Multi-chamber bags

A method for loosening / mixing a concentrate in / with a liquid comprising the steps of: (A) providing a concentrate (5) in powder form, liquid form or semi-liquid slurry form in one of several chambers (2, 3) of a multi-chamber bag (1), wherein the chambers of the multi-chamber bag by a separation means (4, 4a) are separated from each , and (B) introducing a liquid into one of the chambers (2, 3), (C) breaking through the separating device (4, 4a) between the chambers (2, 3) by the introduction of the liquid, and (D) dissolving / mixing of the concentrate (5) in / with the liquid, wherein the multi-compartment pouch is a foil pouch made of an elastically stretchable film, which is elastically stretched by the introduction of the liquid.