Abstract: An apparatus for separating, by pressing, liquid and solid fractions intimately associated in a heterogeneous mixture, such as for example juices, pulps, stones, pits, pips, stalks and vegetable elements of fruits such as wine grapes is characterized in that a vessel (14) is provided having perforate side walls (15, 16) and bounded on its open upstream end by a piston-like member (10, 11) and on its open downstream end by a conical outlet member (50) defining an annular outlet passage, the vessel being filled with the heterogeneous mixture in an upstream-downstream direction thereof, and the vessel then being moved (30, 31) in the opposite, downstream-upstream direction so that the heterogeneous mixture is compressed between the piston-like member (10, 11) and the conical member (50), the pressing force being regulated and modulated for preventing deleterious over-pressing.