1. Cornstarch vs. quick-cooking tapioca: There are many, many thickeners out there, but flour, cornstarch, and quick-cooking tapioca are probably the most popular and each for good reason. Cornstarch has a nice smooth texture and no real flavor, but it can lead to an occasional murky color with berry pies and its thickening power is compromised with high acidity fruit like cherries. Quick-cooking tapioca will never result in a cloudy filling and soaks up really juicy fruit better than anything we've tried. However, it is a little tempermental in the sense that it really needs high heat to activate completely. Make sure to give your pies a good ten minute does of heat at 400 F if you're using this thickener. Flour is an easy thickener in that you generally always have it on hand and it works beautifully. It can lead to a gummy, cloudy filling with delicate summer berries though. We reserve using flour as a thickener for heartier fruits like apples and pears.
2. Pay attention to bake times: one reason you'll often end up with a runny fruit pie is simply that it hasn't been baked long enough. Any thickener you use needs a little time to set up, and people often see their crust turning light brown and think the pie is done when it's really not.
3. Let your fruit sit in sugar for a half an hour and drain the natural juices that will gather. This is especially good to do with peaches or strawberries.
4. Try sprinkling graham cracker crumbs inside your bottom crust; they soak up some of the juices released from fruit during baking.
5. If you want, experiment with twice-baking your crust like Melissa Clark does with her cherry pie. It's not necessary for most fruit pies, but it will result in a firmer crisper pie which many people really like.
The most important thing to remember is to take notes and adapt: Since everyone likes their pie a certain way, when you try a recipe and find it's too set-up or overly runny, take notes and make small changes to apply the next time around. Before you know it, you'll be baking a pie that not only holds up to even the juiciest of summer fruits but also suits your personal tastes perfectly.
(Image: Megan Gordon)