A process for producing poly alpha-1,3-glucan with reduced molecular weight is disclosed. The process comprises contacting water, sucrose, a polar organic solvent, and a glucosyltransferase enzyme in a solution to produce poly alpha-1,3-glucan. This contacting step results in the production of poly alpha-1,3-glucan having a reduced molecular weight compared to the molecular weight of a poly alpha-1,3-glucan made in the absence of the polar organic solvent.