Basic Gluten-Free Flour Mix MAKES 6 CUPS 4 cups super-fine brown rice flour 1⅓ cups potato starch (not potato flour) ⅔ cup tapioca flour/starch 1. To measure flour, use a large spoon to scoop flour into the measuring cup and level it off with the back of a knife. Do not use the measuring cup to scoop your flour when measuring. It will compact the flour and you will wind up with too much for the recipe. 2. Combine all ingredients in a gallon-size zipper-top bag. Shake until well blended. Store in the refrigerator until ready to use.