My answer: There are two basic ways to thicken sauces with flour (particularly gravy).
- Blend 2 tablespoons flour with 3 tablespoons water; stirring constantly add 1 teaspoon at a time to simmering liquid/gravy. Continue adding and stirring until gravy reaches desired thickness; simmer for another 5 to 10 minutes to cook the flour.
- Stir together hot liquid and flour to make a warm paste (this is called a roux). Stirring constantly, begin adding a small amount of the roux to the main hot mixture; add roux and stir to desired consistency and then cook for 5 to 10 minutes to cook the flour (you may or may not need all of the roux). Using the flour method is more advisable if it’s a dish that will be re-heated at a later time. Remember, too, that most cooks have their “tried and true” ways of thickening with flour, so you might want to experiment to find what works best for you.
To thicken gravy or stir fry using cornstarch stir 1 heaping teaspoon cornstarch into 1/4 cup cold water. Add half the mixture to simmering liquid, stirring constantly. Stir and add more cornstarch mixture until desired consistency is reached (cook for a few minutes between additions). Once the consistency looks right, continue cooking and stirring the sauce for 5 minutes to cook the cornstarch. Another round of cornstarch and water mixture may be used if you need more to reach a desired thickness. The cornstarch method is always used in Asian sauces. Cornstarch makes a lighter, clearer sauce or gravy as compared to flour. It does not re-heat as well as sauces made with flour. I personally have better luck with the cornstarch method but I go according to what I’m making.
Is your pasta sauce too thin? Add a tablespoon or two of dry bread crumbs to the pasta sauce. They will absorb some of the unwanted liquid without changing the flavor.
Here’s an article titled, The Five Mother Sauces, from Kitchen Geekery that I found very informative and helpful. Perhaps you will glean something from it too. Thank you, ZZ111, for your question and your interest in Ask Cynthia a Question.