An apparatus for compacting stalk material, having a feeding device for feeding material to be pressed, having at least one pair of press drums which can be driven in opposite directions and which each have circumferential receiving grooves and compression rings in an alternate manner alongside one another in the axial direction, wherein the compression rings of one press drum engage in the receiving grooves of the other press drum, wherein at least one press drum is provided with a cavity and wherein this at least one press drum has a multiplicity of radially extending press channels in a manner distributed over the circumference, said press channels in each case connecting the groove bottom of the receiving grooves to the cavity, provision is made for the compression rings to have a circumferential profile having protrusions formed for example by radially external teeth having tooth tips.