All natural. Tapioca Flour, also known as tapioca starch, is ground to a powdery fine granulation from the dried roots of the cassava plant. It is a starchy and slightly sweet flour that is especially good for thickening soups, sauces, dips, pie fillings and puddings. Tapioca Flour is also an excellent ingredient for gluten-free baking, as it lends a springy texture, promotes browning and makes crispy crusts. Gluten-free. Bob's Red Mill products labeled gluten free are batch tested in our quality control laboratory. We us an ELISA gluten assay test to determine if a product is gluten free.