The invention relates to an apparatus for continuous digestion of wood chip comprising an upright generally cylindrical vessel having a top end and a bottom end. The top end of the cylindrical vessel is adapted to receive wood chips mixed with a cooking liquor to be treated therein. A first conduit is integrally attached at a first location positioned between the top and bottom ends of the vessel for selectively extracting a first quantity of cooking liquor from the vessel. The first location is positioned upstream of a second location within the vessel where the cooking liquor being at substantially full cooking temperature. A second conduit is integrally attached at a third location positioned downstream from the first and second locations of the vessel. The second conduit is in fluid communication with a fourth location positioned at, about below or upstream from the first location for selectively extracting a second quantity of cooking liquor from the vessel at the third location and transporting at least a portion of the extracted second quantity of cooking liquor to the fourth location.