To prevent broth from thinning the flavor of a sauce or gravy, reduce the broth beforehand to concentrate its flavor, or use a roux to thicken the sauce and maintain its richness.
When adding broth to a sauce or gravy, the goal is to enhance the flavor, not dilute it. Here's how to achieve that:
Reduce the Broth: Before incorporating the broth, simmer it in a saucepan over medium heat. This process evaporates excess water, concentrating the broth's natural flavors. Continue simmering until the broth has reduced to the desired intensity. This concentrated broth will add a richer, more pronounced flavor to your sauce.
Make a Roux: A roux is a mixture of equal parts fat (usually butter) and flour, cooked together to thicken sauces. To make a roux, melt butter in a saucepan over medium heat. Add flour and whisk continuously until the mixture forms a smooth paste. Cook the roux for a few minutes, stirring constantly, to cook out the raw flour taste. The color of the roux will depend on how long you cook it; a lighter roux is best for white sauces, while a darker roux is suitable for brown sauces and gravies.
Incorporate the Broth: Gradually whisk the reduced broth into the roux, ensuring there are no lumps. Continue whisking until the sauce is smooth and has reached your desired consistency. The roux will thicken the sauce, preventing the broth from thinning the overall flavor.
Simmer and Season: Once the broth is incorporated, simmer the sauce over low heat for a few minutes to allow the flavors to meld together. Season with salt, pepper, and any other desired herbs or spices to enhance the taste further.
For a gluten-free option, use cornstarch or arrowroot powder instead of flour to create a slurry. Mix equal parts cornstarch/arrowroot powder with cold water, then whisk it into the simmering sauce. Be careful not to overcook, as cornstarch can lose its thickening power with prolonged heat.