Ratio of Cornstarch to Flour

• Substituting cornstarch for flour means you need to make some adjustments. Because cornstarch thickens twice as well as flour, you will need one-half the amount of cornstarch. For example, if your recipe calls for 2 tablespoons of flour for thickening sauces or gravies, you will need 1 tablespoon of cornstarch to produce similar results.

Appearance and Flavor

• Substituting cornstarch for flour in a sauce alters the appearance of the sauce. Foods thickened with flour turn opaque, while cornstarch creates a clear or translucent sauce. Flavor may also be affected, but typically is not an issue. If you prefer glossy, clear gravy, cornstarch may be a better choice than flour. Flour works well with milk-based or cheesy sauces when you want a cloudy or opaque sauce.

How to Use Cornstarch

• Use 1 tablespoon of cornstarch for each 1 cup of broth or sauce to make a thin sauce, or 2 tablespoons for each 1 cup for gravy. Mix the cornstarch in a small bowl with enough cold water to make it pourable. Pour the mixture into the sauce, stirring it constantly to blend it. Bring the sauce to a low boil, while continuing to stir it, and boil for one minute to cook the cornstarch and thicken the sauce.

Advantages of Cornstarch

• Cornstarch cooks evenly and quickly. Flour can leave a pasty flavor in your sauces or gravies if it is not cooked properly, while cornstarch typically does not. Because you need less cornstarch than flour to thicken sauces, using cornstarch also reduces the calories by 47 percent, notes one cornstarch manufacturer.

Other Uses for Cornstarch

• Many fruit pies call for flour as a thickening agent to prevent the pie from being runny. Cornstarch can be substituted for the flour in pie fillings. Follow the instructions for adding the flour to the pie, substituting half as much cornstarch for the flour.