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Apple Pie with Vodka Crust

The Science of Pie – May 19, 2013
Judge’s Favorite Pie
Qiaoyi Wu, Qinqin Chen, Michelle Cheng (Team Aπ3)

Seeking to perfect pie crust texture, team Aπ3 experimented with different liquids that may impede the formation of gluten protein networks. Gluten gives structure and stability to pie dough, but can also make pie dough dense and tough when over-developed. The team examined the porousness, density, and browning of pie crusts prepared with their three different liquids compared to water and concluded that vodka creates the flakiest pie crust.

TeamApi3

photos courtesy of Patrick Tran

Different liquids affect the density of pie crust. (A) Pie crust prepared with alcohol (beer or vodka) is less dense than pie crust prepared with water. Interestingly, carbonated water also lowers the density of the pie crust compared to water. (B-E) Team Aπ3 did not observe much difference in the browning of pie crusts prepared with water (B), carbonated water (C), beer (D), or vodka (E).

The Recipe
Apple pie with vodka crust

For the crust:
1 1/4 cups all purpose flour
1/2 tbsp sugar
1/2 tsp salt
1/2 cup (1 stick) chilled unsalted butter, cut into 1-inch pieces
2 tbsp (approx.) ice water
2 tbsp (approx.) vodka

For the filling:
1/4 cup sugar
2 tbsp all purpose flour
1/4 tsp cinnamon
1 3/4 pounds apples, peeled, quartered, cored, thinly sliced*
*Team Aπ3 used a half Fuji and half Granny Smith apples.

For the streusel topping:
1/2 cup all purpose flour
1/2 cup firmly packed light brown sugar
1/4 tsp ground cinnamon
5 tbsp (2.5 oz) unsalted butter, chilled

Preheat oven to 375F.

To prepare the crust, mix the dry ingredients. Cut in the cubes of butter until the butter forms approximately pea-sized pieces. Add water and vodka one tablespoon at a time, alternating the liquids. Only add liquid until the dough starts to come together and can be formed into a ball. Chill dough for at least 30 min. Roll out the dough and press into a pie pan to form the bottom crust.

To prepare the filling, mix all filling ingredients. Spread the filling mixture on top of the bottom crust. Try to arrange the filling so that the top of the pie is flat.

To prepare the streusel topping, combine the flour, brown sugar, and cinnamon. Cut the butter into small pieces and incorporate into the dry ingredients until the butter is in very small pieces. Spread the streusel topping over the pie filling.

Bake pie at 375F for 45-50 min.

Recipe adapted from Eat Me, Delicious: Apple Pie with Brown Sugar Streusel Topping

Shortbread Apple Pie

The Science of Pie – May 19, 2013
Best Overall Pie
Alia Welsh (Team Sablé)

This solo effort explored the vast parameter space of pie, studying the effect of fat content and temperature on the texture of the shortbread crust, as well as the effect of pH on the browning of the streusel topping. The final winning pie had shortbread made with room temperature standard American butter.

TeamSable

photos courtesy of Patrick Tran

Effect of different fats on the shortbread crust. The quality of the shortbread crust was evaluated based on its color and texture. Porousness (“porosity”) was quantified by converting crust image pixels to black or white, with black pixels representing holes in the crust. A higher percentage of black pixels corresponds to a higher porosity and thus a crumblier crust. The extent of browning was quantified by calculating the RGB values of each crust image and comparing to a “deep golden brown” color standard (RGB 184-134-11). Standard American butter created the most desirable crust in terms of both browning and porosity.

The Recipe
Apple pie with shortbread crust and streusel topping

For the filling:
3-4 Granny Smith apples, peeled and cored
3-4 Fuji apples, peeled and cored
3/4 cup granulated sugar
2 tbsp flour
1/2 tsp salt
1 tsp cinnamon
1/4 tsp nutmeg
1/4 tsp allspice

For the crust:
1 1/4 cups all purpose flour
1/3 cup granulated sugar
1/2 tsp salt
2 sticks of standard American butter at room temperature
1 egg white, separated

For the streusel:
3/4 cup rolled oats
1/2 cup chopped walnuts, pecans, or almonds
1/4 tsp salt
7 tbsp flour
6 tbsp brown sugar
4 tbsp melted butter
2 tbsp honey

Preheat oven to 375F.

To prepare the filling, cut the apples into approximately ¼ inch slices. Combine with the remaining filling ingredients and sautée over low heat until the water from the apples forms a sauce and thickens slightly. Set aside to cool.

To prepare the crust, whisk together flour, sugar, and salt. Cut in the butter with knives or a pastry blender. Pour the mixture into a pie pan and spread evenly with back of a large spoon or measuring cup. The crust should be about 1/2 inch thick.

Bake crust at 375F for about 15 minutes or until the crust is a light golden brown. Allow the crust to cool for 2-3 minutes, then brush with the egg white.

While crust is baking, prepare the streusel. Combine the dry streusel ingredients. Mix in melted butter and honey to form clumps. Set aside.

To assemble the pie, pour filling into the pre-baked, egg-washed crust and sprinkle streusel on top. Bake for about 35 min at 375F. Streusel should be deep golden brown.