The present invention discloses a single-portion package (1) presenting a flow distribution element (4) provided so as to divide the internal volume into a first free space (1.1) and a second compartment (1.2) containing at least one substance, and whereby said flow distribution element (4) is displaced along successive positions along and relative to the sidewall (3.1) under the fluid pressure developing on said first space (1.1), and so that it initially confines said substance and it then confines and/or compresses said substance. The present invention further relates to a system (10) for preparing liquid products and comprising at least two of said single-portion packages (1, 1′) preferentially presenting different flow distribution elements (4, 4′) so that it results for example in different first spaces (1.1, 1.1′) and respective compartments (1.2, 1.2′).