Potato starch starts with washed and peeled raw potatoes. Using high-speed machinery, the starch is extracted from the potatoes, then dried. The result is a very fine, white powder, resembling cornstarch. Potato starch may also be produced as a by-product of processed potato foods, such as French fries or even potato chips.Potato flour, like potato starch, starts with whole potatoes, but this is where their similarities end. The potatoes are cooked, dried, and ground into a fine powder. The result is a powder that’s more beige in color, similar in appearance to whole-wheat flour.Potato flour can be used in conjunction with other types of flour (such as rice flour), for gluten-free baking. However we don’t recommend using it as the sole flour because it holds a lot of moisture and can result in a too-dense, gummy baked good.Starches are a lot easier to substitute for than flour. Here are some common substitutes and ratios:
Cornstarch: Use one tablespoon of cornstarch for every one tablespoon of potato starch.Tapioca Starch: Use two tablespoons of tapioca starch for every one tablespoon of potato starch.Arrowroot Powder: Use one tablespoon of arrowroot powder for every one tablespoon of potato starch.