Disclosed herein are methods of making high molecular weight, reduced viscosity starch pastes by enzymatic conversion. The methods provide a process for producing enzyme-thinned starch pastes that have improved molecular weight distributions, i.e., starch pastes having a more mid to high molecular weight content and less low molecular weight sugars than traditional enzyme converted pastes at similar solids and viscosity. In some embodiments, the methods utilize an enzyme capable of producing longer-chain oligosaccharides rather than low-molecular weight sugars. Other embodiments utilize a combination of enzymes to provide low viscosity pastes that are stabilized against setback and retrogradation. Furthermore, the methods may utilize a continuous starch enzyme cooker for the production of the high molecular weight, reduced viscosity starch pastes.