Tapioca Basics

• Tapioca comes from a tropical tuber called manioc or cassava, one of the world's most important staple foods. It's refined from the dried and ground roots in much the same way potato starch and cornstarch are refined. The pure powder is a potent thickener, but it sometimes develops a strangely stringy texture when cooked. To counter that, it's usually par-cooked and rolled into small balls that absorb liquid and create a jelly-like texture as they cook. Quick-cooking tapioca is milled into smaller, less-noticeable granules. It acts more as a thickener and less as a textural ingredient in its own right.

Making Your Filling

• Substituting quick-cooking tapioca for cornstarch is pretty straightforward. Use about 2 tablespoons of tapioca for every tablespoon of cornstarch in your recipe. Mix it with the sugar and stir it into your berries, simmering them gently until their juices release and thicken. Cool the filling, then spoon it into your prepared pie shells and bake the pies as you normally would. The tapioca will form small, jelly-like balls in the filling, but they'll be masked by the similar texture of the cooked blueberries themselves.

Better Than the Original

• In many respects, quick-cooking tapioca is an improvement over cornstarch. It leaves the cooked blueberry juices perfectly clear and glossy, rather than clouding them as cornstarch sometimes can, and its flavor is perfectly neutral. For bakers who like to prepare lots of pies at once, tapioca has another major advantage. Cornstarch loses much of its thickening power when frozen and thawed, leaving pies with an inconsistent and watery texture. Tapioca-thickened fillings retain their texture much better, making tapioca a superior choice when freezing is in your game plan.

An Alternative Method

• Most blueberry pie recipes call for the filling to be pre-cooked and thickened, but a few bakers prefer the fresh flavor of uncooked berries in their pies. For this method, mix the tapioca with your sugar, then toss the berries with that mixture. Pour them into your shell and bake the pie at 400 degrees Fahrenheit for the first 10 to 15 minutes, to quickly release the blueberries' juices and raise the tapioca to its thickening temperature of 126 to 150 F. Use a deep pie dish, because the juices will bubble freely until they thicken and might otherwise run out over the crust. Reduce the heat to your usual baking temperature to finish the pie.