Ingredient Proportions

Correct amounts of fat and flour—equal parts by weight—are important to a good roux. There must be enough fat to coat all the starch granules, but not too much. In fact, Escoffier called for even less fat than our standard proportions (8 parts fat to 9 parts flour).

A good roux is stiff, not runny or pourable. A roux with too much fat is called a slack roux. Excess fat increases the cost of the roux unnecessarily; the excess fat rises to the top of the sauce, where it either is skimmed off or makes the sauce look greasy.