Abstract: An improved device for wetting a dose of ground coffee in coffee machines, preferably espresso machines, particularly but without limitation professional espresso making machines. The device comprises a source of pressurized water, at least one beverage dispenser unit, a filter holder removably coupled to said dispenser, a water heater placed on the dispenser unit, a water supply system connecting said source of pressurized water with said heater, a dispensing conduit connecting the heater with the dispenser unit, as well as a dispensing valve device inserted in said dispensing conduit for closing and opening the conduit and for feeding heated water to the filter holder and cause it to spread into the dose of ground coffee contained in the filter holder, as well as an electronic control and programming unit connected at least with said source of pressurized water, with said heater and with said dispensing valve device.