A washcoat showerhead for depositing a washcoat onto a face of a substrate comprises a housing having an inlet for receiving the washcoat, a showerhead plate and a baffle. The housing and showerhead plate define a showerhead cavity with the baffle located within the showerhead cavity. The showerhead plate has a plurality of nozzle apertures for discharging the washcoat towards the face of the substrate. The baffle comprises an impermeable central body and a plurality of arms extending from the impermeable central body, the plurality of arms defining a plurality of flow apertures circumferentially arranged around the impermeable central body.