A sauce or gravy is the finishing touch on many dishes, but there are difference between the two. Simply, gravy is the juice and drippings of cooked meat. It can be served as is or thickened with flour. A sauce, on the other hand, is a preparation of several ingredients and is not necessarily meat-based. Variations of brown sauce and brown gravy are found in many regional and world cuisines.
At the heart of French cuisine are the five "mother sauces": bechamel, veloute, tomat, espagnole and hollandaise. They are the foundations for all other sauces. Espagnole, or brown sauce, is a combination of beef stock and tomato purée thickened with a roux (flour and butter paste) and flavoured with a mirepoix (celery, onion and carrots).
Chinese Brown Sauce
Many popular Chinese dishes like beef with broccoli and egg foo yung are made with a rich brown sauce. Each chef has his own recipe, but there are several basic ingredients in most Chinese brown sauces: beef broth, soy sauce and brown sugar. Brown sauce is thickened with cornflour and often seasoned with garlic and ginger. Many recipes also include oyster sauce or hoisin sauce.
The simplest brown gravy is just the jus, or juice, from the meat. Often, cooks will skim the fat from the liquid and serve the gravy as it is. Cooks may also thicken the jus by reducing it. This is done by bringing it to a boil and then to a simmer until half of the volume remains.
In the American South and Midwest, brown gravy is thickened almost to a smooth paste. This type of gravy is made by adding flour and milk to pan drippings and cooking until very thick. It is often served over fried meats and side dishes.