Prepacked serving of coffee powder, particularly for an espresso coffee making machine, comprising a cartridge (1) enclosing a given portion of coffee powder (40), the said cartridge (1) comprising an essentially cylindrical side wall (101) provided at its two ends with a first wall (201) designed to be acted upon by the pressurized hot-water supply means, and with a second wall (301) designed to be acted upon by the brewed coffee dispensing means, the said cartridge (1) being made of an essentially airtight material, and the said wall (301) being continuous and made of a thermoplastic material.