The invention relates to a device (1) for preparing a beverage, in particular for preparing a protein-containing mixed beverage, having the following: a mixing device (100) at least one first container (200) for storing a pourable substrate (210) at least one first supply device (220) which is provided for supplying the pourable substrate (210) out of one of the first containers (200) to the mixing device (100) at least one second container (300) for storing an at least substantially liquid substrate (310) at least one second supply device (320) which is provided for supplying the at least substantially liquid substrate (310) from one of the second containers (300) to the mixing device (100) a third supply device (420) which is provided for supplying a carrier liquid (410) to the mixing device (100) and a dispensing device (500) which is provided for dispensing the beverage into a container (600), in particular a container which can be removed from the device (1). The mixing device (100) is provided for mixing the pourable substrate (210) and the at least substantially liquid substrate (310) with the carrier liquid (410) so as to form a beverage, in particular an at least substantially homogeneous beverage, and to dispense the beverage to the dispensing device (500). The invention further relates to a method for preparing a beverage, in particular for preparing a protein-containing mixed beverage, to a device for storing and supplying a pourable substrate, and to a method for assembling the device for storing and supplying a pourable substrate.
