Tapioca starch (or tapioca flour) is the starch extracted from the cassava root. It is not considered a grain, and is useful in gluten free as well as Paleo baking. It adds crispness and chew to baked goods.
This small container of cornstarch makes it easy to keep some on hand in my pantry. You can keep it filled with cornstarch you buy in bulk from nuts.com or elsewhere.
Expandex Modified Tapioca Starch
Expandex modified tapioca starch is a chemically, not genetically, modified tapioca starch. Use it to build my gluten free bread flour blend and make the best breads of your life.
Potato starch adds lightness to gluten free baking, as well as structure. It's made from peeled potatoes, and has no potato flavor. It is not the same as potato flour.