An espresso coffee machine comprises a boiler and a pump for feeding hot water under pressure to one or more brew groups (1), each of which comprises a receptacle (24) for infusing a predetermined dose of ground coffee, a hot water feed pipe (38) and an outlet pipe (40). Manual operating means (30, 50) are provided at the inlet of each brew group for selectively putting the coffee powder receptacle (24) in communication with the water feed pipe (38), with the outlet pipe 40 or with both the pipes in order to preinfuse the coffee powder.