Flour is made by grinding 2 Wheat, into 1 Flour, you can Bake the Flour in a furnace to make a bread, this process gives your 1 bread per 2 Wheat instead of the usual 1 bread per 3 wheat, the only down side is that you need to power your furnace with something ( charcoal / coal / eletricity from another mod ).

Flour can be made by using the Quartz Grind Stone.

Or you can also use Industrial Craft² Macerator and the Thermal Expantion Pulverizer