How To Choose The Right Thickener For Your Homemade Pie

A cohesive pie filling is as important to texture and integrity as choosing the right kind of pie crust. That's where pie thickeners come into play. We spoke with Joy Wilson, the pro baker and cookbook author behind Joy The Baker, who deems pie thickeners "the quiet heroes of the slice." Of course, thickening agents abound, and Wilson was more than happy to act as a matchmaker, helping us pair the right thickener to the right pie filling, starting with all-purpose flour. The key to choosing the right pie thickener, Wilson reveals, is to "match texture to texture and think ahead."

Just as we use flour for a roux or to thicken Alfredo pasta sauce, it's also a boon to fruit pie fillings. Wilson says that all-purpose flour is "great for rustic fruit pies, especially apple or peach. It's easy, always in the pantry, and thickens slowly and softly." That said, flour doesn't become transparent as it dissolves into the filling liquids. Consequently, says Wilson, "The downsides are that flour can dull the filling color and make things slightly cloudy."

Cornstarch is yet another thickening agent that you'll see more widely used in sweet and savory dishes around the world. However, Wilson thinks its thickening powers are best suited for juicy fruit pies. "It gives a clear, glossy finish," she notes. "But beware: it can turn gummy if overcooked or frozen and thawed." Potato starch may be an unlikely pie thickener, but according to the cookbook author, it's "best for custard-style pies that won't bake long. It thickens quickly at lower temps."

While cornstarch, potato starch, and flour are household staples with uses beyond pie thickening, some other common thickeners are less well-known, though they are perhaps even more well-suited for certain pie fillings. The next set of thickeners on Wilson's list includes quick-cooking tapioca, arrowroot, and instant ClearJel.

Tapioca comes in various forms, and Wilson recommends using quick-cooking tapioca for pie fillings. "[It's] a secret weapon for super-juicy pies like blueberry or fresh strawberry," she explains. "It thickens beautifully, even after freezing." Simply add a tablespoon of tapioca to your dry ingredients like sugar and spices, then mix them with the fruit. Tapioca does take longer to hydrate and thicken, though, notes Wilson, who adds, "Let your filling sit to plump up the ground tapioca before baking."

Arrowroot is a gluten-free thickening agent that, like cornstarch, creates a glossy and clear pie filling consistency. "[Arrowroot is] great for citrus or tropical fruit pies, as it handles acid well, unlike cornstarch," the pro baker reveals. You can try adding it to this tropical passionfruit pie to make what Wilson describes as "a smooth, shiny filling without any starchy taste." Lastly, there's instant ClearJel, which is actually a type of modified cornstarch (and Wilson's preferred all-purpose thickening agent). She calls ClearJel "the pro move," adding that "it's stable, clear, and freeze-thaw friendly. Perfect for pies that'll be frozen or ones you want to slice perfectly."

Certain pie fillings are more amenable to certain thickeners, and Wilson lays down some ground rules. "For super juicy fruits (blueberries, cherries, strawberries), go with tapioca, cornstarch, or ClearJel," she recommends. "For custards and creamy pies, use flour or potato starch. For acidic fruits (lemon, pineapple), arrowroot's your best bet. If you're freezing the pie? ClearJel or tapioca wins the day." We've got dozens of pie recipes to thicken with the indicated ingredient.

Thickeners should be a help, not a hindrance, but according to Wilson, using the wrong thickener "can turn your dreamy pie into a juicy soup or a starchy mess." So, as well as the "dos," it's important to list the "don'ts." Don't add flour to fruit pies because it "might leave it cloudy and very runny," Wilson adds. We noted this when thickening blueberry pie, opting instead for cornstarch or ClearJel. Cornstarch's thickening powers are well documented as the secret weapon behind stir-fry sauces, but even cornstarch doesn't work on every pie filling.

Wilson also advises against adding cornstarch to an acidic pie like lemon pie because, as she says, "acid can break it down and make it weepy, keeping it from thickening properly." Finally, tapioca will likely sabotage the smooth, clean consistency of a cream pie, as it "won't fully dissolve and you'll get little chewy boba-like bits." So the next time you need to choose a thickener for your pie, be sure to think back on Wilson's advice to match texture to texture.