A capsule designed for preparation of a beverage upon injection of liquid under pressure into the capsule, the capsule containing a substance for preparation of the beverage and comprising a cup-shaped body , a top wall and a bottom retaining wall , wherein the capsule further comprises opening means designed to open the retaining wall upon rise in pressure in the capsule , wherein the opening means comprise a plurality of first elements , and secondary elements associated with each first element and facing the retaining wall , the secondary elements associated with a respective first element surrounding at least partially the respective first element and being arranged adjacent to but not in contact with the respective first element , the first elements being non-linear elements, preferably Y-shaped elements, and the secondary elements being linear elements, wherein the secondary elements are arranged at a larger distance to the retaining wall than the first elements are, wherein the retaining wall is a thin film having a thickness of between 15 and 25 microns, wherein the capsule further comprises a series of dispensing holes having a diameter of at least 0.4 mm, preferably at least 0.5mm, and wherein the substance is a precursor ingredient of roast and finely ground coffee, characterized in that , for each first element , the associated secondary elements comprise three linear segments that are arranged to at least partially surround the respective first element , wherein two linear segments are arranged at a medium distance to the retaining wall , and wherein one linear segment is arranged at a larger distance to the retaining wall than the medium distance and is arranged radially outwards with respect to the respective first element . wherein the capsule further comprises opening means designed to open the retaining wall upon rise in pressure in the capsule , wherein the opening means comprise a plurality of first elements , and secondary elements associated with each first element and facing the retaining wall , the secondary elements associated with a respective first element surrounding at least partially the respective first element and being arranged adjacent to but not in contact with the respective first element , the first elements being non-linear elements, preferably Y-shaped elements, and the secondary elements being linear elements, wherein the secondary elements are arranged at a larger distance to the retaining wall than the first elements are, wherein the retaining wall is a thin film having a thickness of between 15 and 25 microns, wherein the capsule further comprises a series of dispensing holes having a diameter of at least 0.4 mm, preferably at least 0.5mm, and wherein the substance is a precursor ingredient of roast and finely ground coffee, characterized in that , for each first element , the associated secondary elements comprise three linear segments that are arranged to at least partially surround the respective first element , wherein two linear segments are arranged at a medium distance to the retaining wall , and wherein one linear segment is arranged at a larger distance to the retaining wall than the medium distance and is arranged radially outwards with respect to the respective first element . <EOS>