Potato starch, also known as potato flour, is a gluten-free flour that you can purchase in specialty stores or in the kosher section of grocery stores. You might want to substitute potato starch for flour when you are thickening sauces or when you are preparing recipes that cannot contain gluten. For example, Jewish people might use potato starch instead of flour during Passover when grain-based flours and thickeners are prohibited. In addition, people who are gluten-intolerant might substitute potato starch for flour as an ingredient in muffins or cookies.
Potato Starch as a Thickener
Divide the amount of flour the recipe calls for by two to calculate how much potato starch to use.
Measure the correct amount of potato starch and mix it in a small bowl with an equal amount of water until it forms a paste.
Mix the potato starch paste into the sauce and continue cooking as directed. However, do not allow a sauce containing potato starch to come to a boil because this will cause the sauce to thin out again.
Potato Starch Baking Mix
Measure 3/4 cup of potato starch or potato flour and put it in a bowl.
Measure 1 cup of rice flour and dump it into the bowl as well.
Measure 1/4 cup of tapioca starch or tapioca flour and put it in the bowl.
Mix the starches together and use them as a substitute for two cups of all-purpose wheat flour.