Detergent compositions are formed into tablets for dispensing. These tablets can be retained in a flexible plastic bag having a rigid opening and tapered midsection. The rigidity of the tablets enables the bag to retain its shape and prevent hydratable detergents from clogging up the dispenser. A preferred detergent formulation is a high-caustic detergent composition which includes a combination of sodium tripolyphosphate and sodium tripolyphosphate hexahydrate, defoaming surfactant, polycarboxylate and a processing and dissolution aid such as propylene glycol. This detergent composition, when tableted, provides an extremely uniform dissolution rate minimizing any temperature peaks that can occur in dispensing high-caustic detergent.