The system comprises: capsules (C) of at least a first type and a second type, having outwardly protruding transverse flanges (32), and respective different axial lengths (h1, h2, h3), and a brewing unit (6, 20, 7), in which there is defined a variable-volume brewing chamber (100) with a lateral delimiting part (81, 81a) and a slidable end delimiting part (54, 55), for receiving capsules (C) of said types introduced into the chamber (100). The capsules (C) of the aforementioned different types have flanges (32) of correspondingly different shapes, and the end delimiting part (54, 55) of the brewing chamber (100) carries stop members (70, 71) adapted to be coupled to the flanges (32) of said different types of capsules (C) when the latter are introduced into the brewing chamber (100), so as to allow correspondingly different relative movements of the end delimiting part (54, 55) relative to the lateral delimiting part (81, 81a) of said chamber (100).