An improved coating apparatus and an improved method of coating a mass of centers are disclosed. The improved coating apparatus comprises a temperature sensor for measuring the temperature of the surface of the coated centers and/or a moisture sensor for measuring the moisture content of the surface of the coated centers. The improved method comprises drying coated centers by measuring the temperature of the surface of the coated centers in the mass using the temperature sensor and adjusting the temperature of the drying gas to maintain the surface temperature of the coated centers at a predetermined temperature and drying the coated centers until the moisture content of the surface of the coated centers is about 0 to about 30 percent water, by weight. Advantageously, the surface temperature and/or surface moisture measurements are conducted during the coating processing of the centers, while the centers are in the coating apparatus.