Thickeners are food substances used to give a thicker consistency to sauces, gravies, puddings, and soups. Common thickeners include:
Flour and cornstarch: All-purpose flour and cornstarch are starches commonly used to thicken saucy mixtures. Cornstarch produces a more translucent mixture than flour and has twice the thickening power. Before adding one to a hot mixture, stir cold water into a small amount. You can also combine either flour or cornstarch with cold water in a screw-top jar and shake until thoroughly blended. It is critical that the starch-water mixture be free of lumps to prevent lumps in your sauce or gravy.
Quick-cooking tapioca: This is a good choice for foods that are going to be frozen because, unlike flour and cornstarch-thickened mixtures, frozen tapioca mixtures retain their thickness when reheated.
Tip: When using tapioca as a thickener for crockery cooking and freezer-bound foods, you can avoid its characteristic lumpy texture by grinding the tapioca with a mortar and pestle before adding to the recipe.