swollen granules give a noticeable initial graininess to sauces However the granules are fragile, and readily fragment into finer particles; so having reached its thickest and grainiest, the consistency of a potato-starch sauce rapidly gets both finer and thinner Potato starch is also unusual for having a large number of attached phosphate groups, which carry a weak electric charge and cause the starch chains to repel each other This repulsion helps keep the starch chains evenly dispersed in a sauce, and contributes to the thickness and clarity of the dispersion and its low tendency to congeal into a gel on cooling Tapioca Tapioca, derived from the root of a tropical plant known as manioc or cassava (Manihot esculenta, p 305), is a root starch used mostly in puddings It tends to form unpleasantly stringy associations in water and so is usually made into large pregelatinized pearls (p 578), which are then cooked only long enough to be softened Because tapioca keeps well in the ground and is processed into starch within days of harvest, it doesn’t develop the strong aromas found in wheat and corn starches or in potato starch, which is typically extracted from long-stored, secondquality tubers Tapioca starch is especially prized for its neutral flavor Properties of Some Common Thickening Starches Cooked in Water Gelation Maximum Temperature Thickness Wheat 126–185ºF 52–85ºC + Corn 144–180ºF 62–80ºC ++ Potato 136–150ºF 58–65ºC +++++ Tapioca 126–150ºF 52–65ºC +++ Arrowroot 140–187ºF 60–86ºC +++ Stability to Prolonged Consistency Cooking ...long enough to be softened Because tapioca keeps well in the ground and is processed into starch within days of harvest, it doesn’t develop the strong aromas found in wheat and corn starches... extracted from long-stored, secondquality tubers Tapioca starch is especially prized for its neutral flavor Properties of Some Common Thickening Starches Cooked in Water Gelation Maximum Temperature... 136–150ºF 58–65ºC +++++ Tapioca 126–150ºF 52–65ºC +++ Arrowroot 140–187ºF 60–86ºC +++ Stability to Prolonged Consistency Cooking