What is the process called of flour thickening sauce?

A roux is a mixture of equal parts fat (usually butter or oil) and flour cooked together, which is used as a base for sauces, soups, and stews. The cooked flour creates a paste that absorbs liquid and thickens it, resulting in a smooth and creamy texture.

Here's a breakdown of the process:

1. Melt fat: Butter or oil is melted in a saucepan over medium heat.

2. Add flour: The flour is added gradually to the melted fat, whisking constantly.

3. Cook: The mixture is cooked until the flour loses its raw taste and turns a light brown color. This process of cooking the flour is called deglazing.

4. Add liquid: The cooked roux is then combined with the liquid (stock, broth, wine, etc.) that you want to thicken.

5. Simmer: The mixture is simmered until the sauce thickens to the desired consistency.

The type of roux used determines the color and flavor of the sauce. White roux, cooked for a short time, has a milder flavor. Blonde roux, cooked for longer, has a nuttier flavor. Dark roux, cooked for the longest time, has a rich, earthy flavor.