When it comes to thickening pie filling, ensure your summer berry pie doesn't turn to soup by using the right tool for the job.
How to Thicken Pie Filling
Updated on Jun. 12, 2025
There are two steps to baking an heirloom-quality fruit pie. First, you’ll need to learn to prepare the perfect flaky butter pie crust. Once you’ve mastered the dough (or found a store-bought pie crust that you love), the next step is making a filling that’s firm enough to hold up on the end of your fork—but not so thick that it turns into a pile of glue. Ready to learn how to thicken pie filling? The secret is in the starch.
Starches have a beautiful ability to thicken sauces, and they can give body to your pie filling. While each thickener works in the same way—by bonding with water molecules and expanding—they all have unique characteristics. You can likely substitute one for another, but it all starts with understanding how each one works and which will work best for your berry pies.
Types of Pie Thickeners
1. All-purpose flour
Flour is a popular thickener for sauces and soups, and it can be used to add body to your fruit filling. It’s great because it thickens at low temperatures, but you’ll need to use more of it because it’s not as effective as some of the other starch options. Most people prefer other thickeners over flour because it creates a cloudy filling with a slightly gummy texture and a wheat-flavored taste.
How much should you use: As a general rule of thumb, use twice as much flour as you would cornstarch or arrowroot.
2. Cornstarch
Cornstarch is an effective thickener that doesn’t need much time to cook, although it does require high temperatures to activate. To avoid clumps, mix cornstarch with sugar before adding it to your filling.
When undercooked or used in excess, cornstarch can have a chalky taste and texture. Also, keep in mind that acidic ingredients (like lemon juice or vinegar) can weaken cornstarch’s ability to thicken, and that it should never be used for pies you intend to freeze—it will turn spongy when thawed.
How much should you use: You’ll need half as much cornstarch as you would flour, but you can substitute cornstarch and arrowroot in equal parts.
3. Arrowroot
Arrowroot is a great non-GMO substitute for cornstarch. Like cornstarch, it must be cooked at high temperatures. It’s not weakened by acidic ingredients, and it freezes exceptionally well. Avoid using arrowroot for cream-based pies, as it creates a slimy texture when combined with dairy.
How much should you use: Arrowroot can be substituted in equal parts for cornstarch.
4. Quick-cooking tapioca
Many people swear by quick-cooking tapioca as a pie thickener. This starch comes from the roots of the manioc or cassava plant, and it’s sold as pre-gelatinized pearls. It requires a low temperature for baking and has a neutral flavor, although it does give the filling a stippled texture that can be slightly gluey, especially when overcooked. Tapioca also needs time to soften, so fillings mixed with tapioca must rest for at least 15 minutes before baking.
How much should you use: Tapioca can be substituted in equal parts for cornstarch or arrowroot.
5. Instant Clear Jel
Instant Clear Jel is a pre-gelatinized, modified food starch derived from waxy maize. It can tolerate a range of temperatures (and can even thicken fruit without any heat at all). It’s used by many commercial bakeries because it works well with acidic ingredients, has a neutral flavor and contributes to clear, cloud-free fillings. Pies made with Instant Clear Jel can also be frozen.
How much should you use: In general, Instant Clear Jel can be substituted in equal parts for tapioca, cornstarch or arrowroot.
Other Considerations
Wondering how much of each thickener to use? It really depends on the type of fruit you’re using. Fruits like apples are high in pectin (a naturally occurring thickener) and don’t release a lot of juice, so you won’t need much thickener for apple pies. Fruits like berries, however, are super juicy and release a lot of liquid as they cook. When combined with sugar, they release even more liquid, so a mixed berry pie requires a decent amount of starch in order to thicken.
No matter what type of fruit you’re using, frozen fruit releases more juice than fresh fruit. When substituting frozen fruit, you’ll need 1/4 teaspoon more thickener per cup of filling.
Keep in mind that lattice-top fruit pies don’t need as much thickener because more moisture can evaporate as the pie bakes. If you’re making an open-topped pie, reduce your thickener by 1/4 teaspoon per cup of filling.
Tips for Making Fruit Pies
What’s the best thickener for fruit pie?
Each pie thickener has its pros and cons, so it may all boil down to what you have on hand. The easiest to reach for is all-purpose flour, but it does give pie filling a cloudier appearance. Instant Clear Jel is the best option overall because of its tolerance to different temperatures, its ability to pair with acidic ingredients, its neutral flavor and its clear appearance.
How much thickener should I use for different fruits?
Fruits like apples and blueberries have natural pectin and a lower water content, so it’s not necessary to use as much thickener. If you’re baking with berries like strawberries, raspberries and blackberries, more thickener is required to make up for how juicy these fruits are.
Can I use pectin or gelatin to thicken fruit pies?
Yes, you can use pectin or gelatin to thicken fruit pies, but these thickeners are generally used when precooking a fruit filling instead of adding fresh fruit and sugar to a pie crust. Pectin gives fillings a firmer, jam-like consistency, while gelatin results in a softer texture.
Do frozen fruits need more thickener than fresh ones?
When frozen fruits thaw, they tend to release more moisture. To account for this, you’ll need slightly more thickener when baking with frozen fruits than you will when baking with fresh fruits.
