Device for the Preparation of a Hot Beverage

A device for preparation of a hot beverage comprising a water tank, a flow heater and a brewing device, the water tank having a connection element for cold water, wherein the water tank is fluidly connected to the flow heater, so that the flow heater can be filled with the cold water from the water tank wherein the water tank comprises a tank bottom, a tank jacket and a tank lid, wherein a piston in the water tank is movable between a top dead center and a bottom dead center, wherein the water tank contains a filling space for the cold water, which is arranged between the piston and the tank bottom when the piston is not located in the bottom dead center, wherein the filling space is fluidly connected to the flow heater, the flow heater can be filled with the cold water from the filling space, so that a quantity of water corresponding to the filling space can be fed into the flow heater.