Watery pie filling
I've tried making 3 cherry pies, a blackberry pie and an apple pie this year and no matter what thickening agent I use (flour, cornstarch or tapioca), the filling always turns out watery and never really gels up. The flavor of the pie is fine, but just soupy. What am I doing wrong?
Not using enough thickening agent, or not baking the pie long enough/at a high enough temperature to activate its thickening properties, most likely. For instance, for sour cherry pie, I use 4T. of tapioca to 6 cups of cherries, and bake the pie for usually 30 mins at 450, then another 30-40 at 375. This is no fail for me.
I only use flour to thicken apple pies - maybe 2-3T. per pie? I use a mix of tart and sweet apples and microwave them first to get their juices flowing and set the pectin. This also helps me estimate how much flour I'll need, since I can see how juicy my fruit is. Again, the pie needs to bake a lot longer than you might think to set up properly - I usually make deep dish apple pies and they're in the oven for at least 1.5 hours.
I used to use cornstarch to thicken other fruit pies, but it can be problematic because its thickening properties can be compromised by acidic foods. However, many hounds have reported good success with a method in which you cook part of the fruit and all of the sugar for your pie on the stove top, then add the cornstarch slurry and cook it on the stovetop until it thickens, then mix it with the rest of your fruit and put it in the pie.
I agree - The problem is you are not cooking it long enough. Make sure to cook it until it hits at least 170 F and don't cut it until it cools.