Starch in Classic French Sauces

In the code formalized by Auguste Escoffier in 1902, there are three leading mother sauces that are thickened in part with flour: the stock-based brown and white sauces, or espagnole and velouté; and the milk-based béchamel. Each of these relies on a distinctive combination of roux and liquid. Brown sauce consists of a stock made from browned vegetables, meat, and bones, then reduced after thickening with a roux that is cooked until the flour browns as well. White sauce uses a stock made from un browned meat, vegetables, and bones, and is bound with a pale yellow roux. Béchamel combines milk with a roux that is not allowed to change color at all. From these three parent sauces, the cook can produce scores of offspring simply by finishing the sauce with different seasonings and enrichments.