Roux & Lumps: The Technique Guide

The technique under every gravy on this site: how a roux works, why lumps form, and how to fix them. Master these eight points and the whole Gravy Catalog opens up.

Topic	The method
The roux ratio	One tablespoon of fat and one tablespoon of flour thicken about one cup of liquid to a medium gravy. Scale up for thicker, down for thinner, and cook the roux a full minute before any liquid goes in.
Fat first	Use the fat the dish gives you: drippings carry the flavor of the meat they came from. Measure the fat before adding flour, because too little fat makes a pasty roux that no whisking rescues.
Color is flavor	A white roux thickens most and flavors least; blond adds toastiness; brown and dark roux thicken less per spoon but taste deepest. Milk gravies stop at white or blond; Louisiana roux goes dark.
Why lumps form	Lumps are dry flour pockets sealed by hot liquid. They form when liquid lands too fast, when the liquid and roux are the same temperature, or when whisking stops at the simmer. Prevention is easier than cure.
The lump fix	Whisk hard at a rolling simmer first; most lumps cook out. For stubborn ones, strain the gravy or blend it briefly, then return it to the heat. Never add raw flour to a finished gravy.
Liquid temperature	Add cold or room-temperature liquid to a hot roux, or hot liquid to a cooled roux — opposites prevent lumps. Add the first splash slowly, whisk it smooth, then pour the rest with confidence.
Season at the end	Gravy reduces and concentrates as it simmers, and drippings vary in salt from pan to pan. Salt and pepper go in after thickening, tasted off the spoon it will be served with.
Holding and reheating	Gravy skins as it sits: press wrap onto the surface or whisk in a spoon of milk. Reheat gently with a splash of milk or stock, whisking, because a thickened gravy always sets firmer than it served.