Disclosed are method and apparatus for operating a multi-stage process. The stages of the process are carried out in a plurality of modules arranged in sequence to receive individual batches of goods to be processed. Formulas may be devised whereby particular process steps may be effected in the various modules on particular batches of goods which determine the choice of formula. In a particular embodiment disclosed, a controller operates a continuous batch washing system according to formulas devised to operate the modules of the washing system to accommodate particular wash requirements of the batches of goods. Continuous access to the controller is provided for modification of the formulas.