What is the culinary term for a mixture of flour and fat used in sauces?

The culinary term for a mixture of flour and fat used in sauces is roux. Roux serves as a thickening agent and is foundational in many classic sauces, especially in French cuisine. When flour is cooked in fat—commonly butter—the resulting mixture can be used to create velouté, béchamel, or other sauces that benefit from its thickening properties.

Roux is typically prepared by heating equal parts of flour and fat over a low heat until the flour is thoroughly cooked, allowing it to lose its raw taste. Depending on the cooking time, roux can vary in color from white (for light sauces) to darker shades (for sauces with deeper flavor profiles).

The other options do not pertain to the mixture of flour and fat. Pasta refers to a type of dough made primarily from flour and water, shaped and cooked into a variety of forms. Brine is a saltwater solution used for preserving food or enhancing flavor. Emulsion is a mixture of two liquids that usually do not mix well, like oil and vinegar, and involves methods of combining them to create a stable mixture. Thus, the understanding of roux is essential for anyone practicing techniques in sauce preparation.