The gluten network in a bagel vs. a pie

Gluten develops in dough when two wheat proteins found in flour (glutenin and gliadin) are mixed with water. Because parts of these proteins don’t like to interact with water, the proteins begin to stick to each other much in the same way oil droplets come together when suspended in water. As a flour-water dough is mixed, the glutenin and gliadin molecules interact to form a protein network.

These networks give structure and stability to dough. Although dense networks are great for chewy bread dough, they are less than ideal for flaky, tender pie crust. An ideal pie dough has as just enough gluten to hold everything in the dough together. And while gluten development can be minimized by adding only scant amounts of water and handling the dough as little as possible, this is easier said than done.

What flour is the best flour for pie crust? This is a contentious question that has a variety of answers depending on personal preference, but the type of flour you use can have a major effect on the final texture of your crust. The protein content of flour, based on the type of wheat the flour was made from, will affect the extent of gluten formation in your dough. Bread flour has particularly high protein content, which can make pie crust dense and tough. Flours with lower protein content, such as pastry flour or cake flour, will create less extensive gluten networks and can produce a more tender crust.

Use science to make the best pie ever:

Make The Best Pie Ever Using Science

One of the staples of the holiday season is pie and while you may have Grandma’s recipe for the perfect crust, do you really know what goes on at a molecular level? UCLA biophysicist Amy Rowat shares some of the scientific aspects of apple pie and explains how you can apply these insights in the kitchen.

1.    Think of butter as a gas.

Butter is really just a bunch of teeny tiny water droplets dispersed in a matrix of fat. In the oven, these water droplets convert from liquid to gas. This means that the chunks of butter you can see in your dough are really just big pockets of air waiting to happen. More air = flakier crust! While butters with the highest butterfat content are generally synonymous with the highest quality butter, when it comes to baking pie a slightly lower fat content, and higher water content, may be a good thing.

2.    Experiment with the liquids you add to your pie dough
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Gluten gives structure and stability to pie dough, but can also make pie dough dense and tough when over-developed. Typically water is added to create pie dough, but you can experiment with different liquids —like vodka, rum or even carbonated water— that impede the formation of gluten protein networks.

 3.    Sometimes the best pie is a day-old pie.
Temperature is important for pie texture. Because molecules flow more quickly past each other at higher temperatures, hot pie filling straight from the oven will be more runny; as the pie filling cools, starchy molecules like cornstarch and flour spend more time interacting with each other. As the pie cools, the pectin molecules of your fruit also spend more time interacting with each other. This results in a more solid, gel-like filling that will take longer to seep out of the pie when it is cut and served on a plate.

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