On thickening summer fruit pies
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 temperamental 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.