This invention is directed to a method for cooking wood chips in a digester for the separation of wood fibers from their bonded state, the digester having a vertical centerline, a substantially circular cross-section, and a wash zone adjacent the bottom end thereof and a plurality of individual wash screens disposed about the inner wall of the digester for the withdrawal of liquor from the wash zone. In the first step of the method, substantially equal volumes of liquor are dynamically withdrawn from the wash zone through individual ones of the wash screens, while monitoring of the flow rate of liquor exiting the digester through individual ones of the wash screens. The monitored flow rate is used to increase or decrease the flow rate from screens to a value substantially equal to the flow rate of liquor from the digester through each of the screens. As a result, the total volume of liquor exiting the digester through the screens is divided into equal volumes flowing from the wash zone of the digester through each of the wash screens. The equal volumes were extracted substantially simultaneously in a flow direction substantially radially of the digester about substantially the entire circumference of the digester and within a plane disposed substantially perpendicular to the vertical axis of the digester.