Abstract: Apparatus for forming a cake of compressed plant material, comprising a bottom die having a cylindrical upper portion, an inverted conical lower portion and a post extending vertically upwardly from a small-diameter region of the lower portion, wherein plant material is introducible into a cavity of the bottom die surrounding the post; a top die designed and configured to conform to the cylindrical upper portion and the post and having an inverted conical lower portion with a narrower diameter than a corresponding portion in the bottom die; a power train operable to drive the top die into the bottom die so as to be in pressing relation with the plant material interposed between the top and bottom dies for a sufficient duration to produce a cake of compressed plant material.