Use cornstarch, flour, or tapioca to thicken the filling
One of the most common ways to thicken sweet potato pie filling is to use cornstarch, flour, or tapioca. Here’s a quick overview of each:
Cornstarch
Cornstarch is an excellent thickener for sweet potato pie filling. It has several advantages:
– It dissolves completely into the filling, so you don’t get any starchy taste or gritty texture.
– It thickens at relatively low temperatures, so you can add it right before baking without pre-cooking.
– It creates a nice clear, glossy filling without being hazy.
The typical ratio is 1-2 tablespoons of cornstarch per 1 cup of sweet potato puree. Mix the cornstarch with a bit of water or juice first to form a slurry before adding it to the rest of the ingredients. Bring the filling to a simmer to fully thicken.
All-Purpose Flour
All-purpose flour can also be used to thicken sweet potato pie filling. Some bakers prefer flour over cornstarch for flavor and texture.
Pros of using flour:
– Adds structure and body to the filling. The texture is slightly less creamy than cornstarch.
– Imparts a subtle raw flour taste that some people enjoy in pie filling.
The downside is that flour-thickened fillings can sometimes be opaque and cloudy looking. They also need to be cooked longer to eliminate any raw flour taste.
Use 2-3 tablespoons of flour per 1 cup of sweet potato puree. Whisk the flour into the puree until smooth before adding other ingredients. Cook for at least 5 minutes to eliminate rawness.
Tapioca
Tapioca starch (also sometimes called tapioca flour) is another option for thickening sweet potato pie.
Advantages of tapioca:
– Provides a clear, glossy appearance to the filling.
– Creates a thick, clingy texture that’s slightly elastic.
– Can be used interchangeably with cornstarch.
One downside is that tapioca requires pre-cooking with the pie filling to fully thicken. Use a ratio of 1-2 tablespoons per cup of puree.
So in summary, cornstarch, all-purpose flour, and tapioca starch are three great choices for thickening sweet potato pie filling. Cornstarch gives a smooth, glossy texture; flour provides structure and flavor; and tapioca makes the filling clingy and elastic.
Cook the filling down to evaporate excess moisture
In addition to adding a thickener, you can also cook the sweet potato filling down for a longer time to thicken it through evaporation.
Here are some tips for thickening the filling by cooking:
– Make sure to drain any excess water or milk from the sweet potato puree so your filling isn’t too thin from the start. Press the puree through a mesh strainer or cheesecloth.
– Cook the filling over medium heat in a wide skillet or pan, not just a saucepan. The increased surface area speeds up evaporation.
– Stir the filling frequently as it cooks and begins to bubble. Constant stirring prevents scorching on the bottom.
– Cook for 10-15 minutes once boiling to allow excess moisture to cook off. The filling with thicken to the perfect consistency.
– Watch closely near the end to prevent burning. Turn down heat if needed.
– Let the filling cool slightly and then taste before baking. Adjust seasonings as needed once thickened.
With this method you don’t need to use as much thickener. But the filling does need prolonged cooking and stirring, so keep that time commitment in mind.
Add eggs to enrich the filling
Another way to improve the consistency of sweet potato pie filling is to add eggs, either whole eggs or egg yolks only.
Eggs function as a natural thickener andalso enrich the filling:
– The proteins in eggs coagulate when heated to a high enough temperature, which increases the viscosity of the pie filling.
– Egg yolks in particular contain emulsifiers like lecithin that helps thicken and bind ingredients.
– Whole eggs or extra yolks make the filling more decadent, custard-like, and velvety. The added fat prevents a gelatinous texture.
– Yolks alone give the filling an extra smooth, creamy richness without lightening the color like egg whites would.
When adding eggs, keep the filling below a boil to prevent curdling and scrambling. A gentle simmer is ideal once eggs are added.
Here are two recommended recipes:
2-3 whole eggs per pie
Or
4-5 egg yolks per pie
The eggs work together with your preferred starch thickener like cornstarch or tapioca. For a 9 inch pie, aim for 1-2 tablespoons starch and 2-3 eggs.
Use sweet potato varieties lower in moisture
Some varieties of sweet potato naturally have a thicker, denser flesh that requires less moisture to puree. Choosing one of these drier varieties can cut down on extra water needed in the filling.
The two best sweet potato varieties for dense, thick pie filling are:
Jersey Sweet Potatoes
– Oblong shape with tan, copper-colored skin
– Firm, dense orange flesh
– Low moisture content
– Rich, sweet flavor good for baking
Jewel Sweet Potatoes
– Round shape with copper skin and dark orange flesh
– Very dense texture
– Cooks down into a thicker puree
– Intense sweet potato flavor
Other good options: Orleans, Beauregard, Hernandez.
Avoid moister, softer varieties like Garnet Sweet Potatoes which have a higher water content. Consult local farmers to find the best regional sweet potato varieties for baking.
Blind bake the pie crust first
Pre-baking the pie crust before adding the filling (called blind baking) allows you to thicken the filling as much as needed without overcooking the crust.
Steps for blind baking:
1. Roll out dough and fit into pie dish. Trim edges.
2. Line crust with parchment and fill with pie weights or dry beans/rice.
3. Bake at 375°F for 15-20 minutes until lightly browned.
4. Remove weights and parchment. Bake 5 minutes more to dry out crust. Cool.
5. Fill pre-baked crust with the thickened filling and continue baking at 350°F until set, about 30 more minutes.
The pre-baked empty crust gives you more control over the thickening process. You can cook the filling as long as needed to reach the right consistency before adding it to the crust.
Add gelatin to bind the filling
For a firm, sliceable sweet potato pie, adding unflavored gelatin can help bind and stabilize an otherwise runny filling. Gelatin gives it an evenly thick, pudding-like texture.
Quick tips for using gelatin:
– Use 1 teaspoon unflavored powdered gelatin per 1 cup mashed sweet potato
– Sprinkle gelatin over 2 tablespoons cold water and let soften 5 minutes
– Heat sweet potato puree to a simmer and stir in bloomed gelatin
– This helps evenly distribute gelatin as it melts into the hot filling
– Remove from heat and fill baked pie crust as usual
– Chill pie at least 4 hours for gelatin to fully set the filling
Only a small amount of gelatin is needed to bind the moisture. Too much can make the filling rubbery. 1 teaspoon per cup is a good starting point.
Adjust oven temperature and baking time
For thicker filling, you can also manipulate the baking conditions:
Lower oven temperature: Bake at 325-350°F instead of 375°F. The more gentle heat gives the filling more time to gradually set up without overcooking the crust.
Tent with foil: Covering the edges of the crust with strips of foil prevents excessive browning of the crust edges so the center can bake longer.
Water bath: Placing the pie dish on a baking sheet with a water bath protects the filling from drying out. The moisture helps cook the filling evenly.
Convection setting: The circulating air of a convection oven also creates a moist environment for even baking.
Check often: Check the pie regularly as it bakes and continue baking until the center filling is set and no longer jiggles when gently shaken.
Use these tips combine to allow the filling to cook to a thicker final consistency in the oven.
Let pie filling fully cool and set before slicing
After baking the pie, allow it to fully cool at room temperature for at least 4-6 hours to allow the filling to set.
A warm or hot pie will seem much more runny. As it cools, the filling will continue to thicken and become sliceable.
Chilling overnight in the refrigerator is even better. The cooled filling firms up considerably.
Quick chilling in the freezer for 1-2 hours can also help the filling set up if you need to serve the pie sooner. Keep an eye so it doesn’t freeze solid.
Being patient and allowing the pie to fully cool gives you the truest sense of the final texture. Then you can adjust the thickener if needed next time.
Adjust thickeners and egg ratio in your recipe
If your pie filling is too thin, bump up the thickener – try an extra tablespoon of cornstarch or flour per cup of sweet potato puree. Or add another egg yolk or two for more richness.
If the filling seems rubbery or gelatinous from too much thickener, decrease the amount next time or skip additional eggs.
Write down any adjustments you made so you know for next time. It may take some trial and error to get the filling thickness exactly how you prefer.
Conclusion
Achieving the perfect luscious yet sliceable sweet potato pie filling takes a balance of ingredients and techniques. Use starch thickeners, prolonged cooking, egg enrichment, baking adjustments, and cooling time to get the ideal texture your family will love. Play with different varieties of sweet potatoes and amounts of eggs and thickener until you find your ideal ratio. With a few tweaks, you can learn how to thicken up sweet potato pie filling to hit that sweet spot every time.