A method for filtering suspended materials from a cooking substance, e.g. oil or shortening, in a central filtration system 100. The method including the steps of (i) receiving the cooking substance in a first tank 106 from a deep fryer and filtering in a first filtration stage through a separator 112 and returning to the first tank 106; (ii) transitioning to a second stage by filling a second tank 118; (iii) filtering in a second filtration stage through filters 120 and 112; and (iv) holding the cooking substance in a heated tank 126 before returning to the deep fryer. Each stage commences when a certain condition is met, e.g. a predetermine level or weight of cooking substance in a tank or a predetermined clarity of the cooking substance.