grist for the mill

Grist for the mill is an idiom that refers to the fact that all things can be a potential source of profit or advantage. This phrase originates from grist which is the corn brought to a mill to be ground into flour, and has been used by farmers for many years as the grist would be a source of profit for them. Therefore, when someone says grist for the mill they mean that the topic at hand has good potential at bringing in a profit or another type of advantage.