Processes for manufacturing starch copolymer compositions are provided. In one process, a modified starch is reacted with a hydrophilic vinyl monomer to produce a starch copolymer gel which is, in turn, divided in a plurality of gel fragments. The gel fragments are then dried with a stream of gel to produce a flowable, particulate starch copolymer composition. In another process, water is evaporated from the copolymer gel and further polymerization of vinyl monomers is inhibited during the evaporating by any of a variety of means such as reducing the level of residual vinyl monomer or avoiding conditions which initiate polymerization.