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Thicken Pie: Cornstarch, Tapioca, Flour and more…

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pie thicken filling

Pie Thickeners

Which one should I use?

What is the difference between cornstarch, tapioca and flour?

Shhh.. the secret thickener used by bakers

Thickeners for Pie Juicy Fillings

The starch thickener for a pie filling is one of the most important ingredients in pie making. A pie with a watery filling resulting from not enough thickener and a pie with a pasty or rubbery filling resulting from too much thickener are equally undesirable.

The most common thickeners used for pie fillings are flour, cornstarch and tapioca. These starches all work well to thicken pie filling juices but not of equal power.

All thickeners have advantages and disadvantage. The trick is to use just the right amount to achieve the desired thickness after the pie is baked.

How flour, cornstarch, arrowroot and starches thicken pie fillings:

Heat causes the starch in the thickeners to bond with water molecules. The starch granules then start to enlarge like a balloon, absorbing the water around it as it swells.

As the temperature rises over 150 degrees F and up to a point just below boiling, the rigid structure of the starch separates, creating a spidery web net of bonded starch and water molecules.

This net prevents the free movement of water molecules and results in a thick sauce. You can notice that at this point the sauce becomes clearer. That is because the starch molecules are no longer packed tightly together. They are in a looser meshwork and spread further apart after heating up. Therefore, light is less likely to be deflected by the starch.

If the starch is over heated above 205 degrees F for a long period, the large starch balloons start to shrink in size, releasing the water it once held. As this happens the filling becomes thinner.

As the starch granules absorb the liquid, they swell like starchy balloons and become fragile. It is very important when making a pudding or glaze not to stir vigorously after thickening has occurred, because you will break down these fragile starch balloons.

The amount of thickener, starch, to use:

If you are using more sugar in a pie filling than the recipe calls for, more thickener will be needed because sugar contains moisture and when cooked, it will produce more juices, especially with berries.

The same amount of thickener needed for a pie that is baked with fresh to frozen fruit or berries will not be the same. Frozen will most likely need a little more thickening.

Tapioca and cassave
are basically the same thing.
Tapioca is made from dried cassava
but formed into tiny pearls.

If baking a pie to eat shortly after leaving the oven due to the shortage of time you can replace half the cornstarch with cassava. The pie will not need to cool down as much and make the filling firm enough to slice and eat.

For example: replace 2 tablespoons of cornstarch with 1 tablespoon of cornstarch and 1 tablespoon plus 1 teaspoon of cassava.

2 tbsp of cornstarch = 1 tbsp of cornstarch + 1 tbsp of cassava + 1 tsp of cassava

If making a pie to eat the following day, reduce the amount of thickening. The thickener will continue to thicken over a 24-hour period.

Use less thickening for open-faced pies

For a lattice or open-faced pie, use a little less thickening than for a double crust pie, because more of the liquid will evaporate during the baking process.

The average amount of cornstarch for 4 ounces of fruit is 1 to 2 teaspoons.

Substituting thickener

Should you want to experiment with tapioca or cassava flour, they are equal to corn??starch by weight but not by volume:

1 tablespoon of cornstarch or fine tapioca = 4 teaspoons of cassava flour.

1 tablespoon of cassava flour = 2 1/2 teaspoons plus 1/4 teaspoon of cornstarch or fine tapioca

Pie Thickeners in detail

Cornstarch – Pie Filling Thickener


Corn starch is somewhat flavorless, silky and thickens the pie filling at boiling point.

Wheat Flour – Pie Filling Thickener

best apple pie recipes

Wheat flour is a very stable thickener for pie fillings.

ClearGel ® The Best Pie Thickener

clearjel clear gel thicken

A secret no more. The failsafe way to thicken your fruit pies.

Tapioca – Pie Filling Thickener

tapioca thicken pie filling

It gives a transparent gloss to fruits.

Arrowroot – Fruit Glaze

arrowroot pie thickening and fruit glaze

Do not use as a pie thickener.