There are several substitutes for tapioca, and the one that will work best varies depending on the product. Tapioca is used as a thickening agent in many dishes. The three kinds of tapioca most commonly used for cooking are instant tapioca, tapioca pearls, and tapioca starch.
Tapioca is made from the root of the cassava, or yuca plant. Cassava is a shrub that grows in South America. The roots must be carefully processed because they contain poisonous substances. First, the roots are shredded, the juice squeezed out, then the rest is heated and dried into flour. In some parts of the world, cassava flour makes up a main portion of the diet.
Pearl tapioca can be used in pies and for tapioca pudding, although instant tapioca is better for pudding. One drawback is that the pearls must be soaked for several hours before using. They also leave lumps in the finished product.
Tapioca starch or flour is the ground form. It thickens without causing lumps. Other good qualities are that it dissolves very quickly and gives a chewy texture.
The primary use for tapioca is to thicken desserts. It can also be used for gravies and soups, but it adds a glossy sheen which might be undesirable for these dishes. Substitutes for tapioca can be used if it is not available or if a glossy look is not wanted.
Among the common substitutes for tapioca is cornstarch. You should use half as much cornstarch as you would tapioca. This is a common thickening agent and readily available. The downsides are that it does not dissolve as easily as tapioca, and it will separate if frozen.
ClearJel® and Instant ClearJel® are two products made from modified cornstarch. They are used in both canning and for pie fillings in place of tapioca. Neither need to be cooked to thicken. Regular ClearJel® does not freeze well.
Arrowroot is another of the more common substitutes for tapioca. It is better in some dishes than cornstarch since it has a neutral flavor. Another advantage is that it freezes well. It is more expensive than other options, though, and cannot be mixed with dairy products.
Less common substitutes for tapioca include kudzu powder, lotus root flour, and potato starch. Kudzu powder is very expensive because it has purported medicinal properties. It comes in chunks which must be crushed into a powder and mixed with water. Lotus root flour is gluten free, so it is good for people with restrictive diets. Potato starch is also gluten free, but must not be boiled.