Which technique is generally used to add texture to sauces?

Incorporating thickening agents like flour is a common technique used to add texture to sauces. This method alters the consistency and viscosity, transforming a thin liquid into a thicker, more substantial sauce that can cling to food and enhance the overall mouthfeel. This is achieved through various processes, such as making a roux, where flour is cooked with fat, or by adding flour directly to a sauce to create a velvety, smooth texture.

While the other techniques mentioned can influence a sauce's characteristics in different ways, they do not specifically focus on enhancing texture in the same manner. For instance, simmering without stirring would primarily affect the reduction and concentration of flavors rather than the texture. Emulsifying oils and vinegar is essential for creating stable dressings or sauces, but it serves more to blend different phases together rather than thicken them. Straining out all solid ingredients would actually lead to a thinner sauce, lacking in the body that a thickening agent would provide. Therefore, using thickening agents like flour is the most straightforward method for achieving the desired texture in sauces.