The term "tapioca" refers to a starch derived from the root of the manioc or cassava plant, a woody shrub originally native to South America. This starch may be made into colored sticks, large or small pearls, or used on its own for pies and desserts. Cooking tapioca requires different techniques depending on the form required by the recipe, but usually involves soaking the material, then boiling or simmering it in hot liquid. Over-soaking or excessively long cook times can cause tapioca sticks or pearls to break down unto an undesirable ooze, while under-cooking tapioca produces a crunchy product.
Tapioca comes from the roots of the cassava plant, also called the manioc, tapioca plant, and boba, and is originally native to the Amazon. This starch is now grown around the world and is used extensively in south and southeast Asia, as well as in English-speaking countries. Tapioca is gluten-free and contains few proteins, making it a suitable food ingredient for many people on restricted diets. When tapioca is not readily available, cooks can substitute other starches, such as corn starch for tapioca dishes not containing acids, or arrowroot for non-dairy dishes.
Tapioca starch may be used as a thickener for pies and puddings, as it produces a glossy, attractive gel when mixed with cold water and heated, but it produces a stringy, unattractive result in gravy or soups. The starch can also be made into small tapioca pearls used in traditional British tapioca pudding and in some recipes that call for tapioca pie thickeners. Other tapioca desserts, such as coconut dessert soup and bubble tea, rely on large tapioca pearls, which have a chewier texture. In Asia, tapioca is often made into brightly-colored sticks, which are boiled and used as an interesting textural ingredient in sweet drinks and desserts.
Almost all methods for cooking tapioca require soaking it in water or another liquid before heating, which produces the desirable chewy result. Large tapioca pearls should soak for about 2 hours, while smaller pearls or tapioca sticks usually take less time. When fully soaked, the tapioca should have a squishy outside surface and a pasty look at the center. Some products, such as instant or quick-cooking tapioca and tapioca starch, do not require this soaking step.
Cooks should take care not to soak tapioca until the center becomes soft, as it will disintegrate during the cooking process. This may also occur if the tapioca is cooked for a very long time at high heat. Failure to soak tapioca or cooking it for a very short time may produce tapioca pearls with a hard and crunchy center, or puddings and pie fillings that fail to gel properly.