Fresh Fruit or Canned Filling?

Fruit pie fillings are made from cooked or uncooked fresh or dried fruit. The fruit is assembled in an unbaked bottom crust, with or without a top crust made from a pastry dough or crumb mixture. Crust(s) and fillings bake together.
Thickeners are used in juicy fruit pies so the liquid that come from fruit when baked gels. Without them you will have baked fruit in a puddle of juice. Better to have the juices remain around the fruit to make use of all the fruit's flavor.
Typical thickeners for fruit pies include the obvious thickeners (flour, cornstarch, tapioca, arrowroot) and the not-so-obvious (ClearJel and potato starch) and several combinations (flour-cornstarch, tapioca-cornstarch). All are available in the supermarket, except for the combination thickener which you mix yourself with equal parts. The amount needed varies with the kind of fruit and the quantity of sugar used. However, I must warn you that everyone has their favorite thickener and will swear by it as the very best! But, certain thickeners are best used with certain types of fruit.
In general, fruit fillings thickened with arrowroot and tapioca, were clear and bright in appearance, and the flavor of the fruit came through clearly. Of the two, tapioca showed a bit more thickening power and was therefore my favorite. When making a lattice-top pie, the tapioca on top of the fruit baked into hard bits, so first grind it into a fine powder and use ClearJel® or Potato Starch can be used as a good thickener.