A roux must be cooked so the finished sauce does not have the raw, starchy taste of flour. The three kinds of roux differ in how much they are cooked.
- White roux is cooked for just a few minutes, just enough to cook out the raw taste. Cooking is stopped as soon as the roux has a frothy, chalky, slightly gritty appearance, before it has begun to color. White roux is used for béchamel and other white sauces based on milk. In spite of its name, white roux is actually a pale yellow because it is made from butter and (usually) unbleached flour. Figure 8.8 illustrates the production of white roux.
- Blond roux, or pale roux, is cooked a little longer, just until the roux begins to change to a slightly darker color. Cooking must then be stopped. Blond roux is used for veloutés, or sauces based on white stocks. The sauces have a pale ivory color.
- Brown roux is cooked until it takes on a light brown color and a nutty aroma. Cooking must take place over low heat so the roux browns evenly without scorching. For a deeper brown roux, the flour may be browned in an oven before adding it to the fat. A heavily browned roux has only about one-third the thickening power of white roux, but it contributes flavor and color to brown sauces.