A process for making cellulose acetate or cellulose esters which pretreats a wood pulp prior to acetylation or esterification is disclosed. The pretreatment of the wood pulp includes the mixture of wood pulp into a caustic solution to form a suspension of wood pulp. The suspension of wood pulp is separated from the caustic solution to form a cake. The cake is washed with an acid to obtain an acid and cellulose cake having a low water content. The acid and cellulose cake is then acetylated or esterifed to form cellulose acetate or other cellulose esters.