A boiler (100) for a machine for preparing beverages, intended to heat a liquid pressurized to at least 8 bars, so that the heated liquid can brew a product, with the boiler including: a body (1) having an outer wall (2) covered with a screen-printed resistance (14) and an inner wall (3); the inner wall (3) of the body (1) having a longitudinal wall (4) which has a circular cross-section, as well as a bottom wall (5); an inner element (30) having an outer face (35) for defining, together with the longitudinal wall (4), at least a portion of heating chamber (102); a liquid inlet (10) and outlet (12); a support (20) so configured as to cooperate with the body (1) so as to form, together with the longitudinal wall (4) and the bottom wall (5), a sealed enclosure (101) including the heating chamber (102).