The Life of Pie: The Science Behind Piecrusts

Thanksgiving is around the corner, which may bring to mind turkey, sweet cranberry sauce, or stuffing. Yet, it may also evoke a particular dessert: pies. Around this time of year, stores are brimming with ingredients to make all sorts of pies in lieu of the season. Whether or not you’re making your own pies, and whether or not you’re making the piecrust from scratch, this article will cover the science behind forming the best flakey crust.

Image courtesy of Publicpicturesdomain.net
Image courtesy of Publicpicturesdomain.net

The life of pie

The perfect pie should have the perfect crust. Above all else, the crust should be bursting with buttery goodness, which all but explodes with flavor with the first bite. The foundation of the piecrust is made of three ingredients: flour, water, and fat. When done correctly, the crust is substantial enough to resist the sogginess characteristic of subpar pie. It should flake, not crumble—simple, yet delicious.

How flakey are you?

Image courtesy of Jessica Trinh
Image courtesy of Jessica Trinh

Butter is often used as the fat element because it contains water, which is crucial to the formation of a flaky crust—not to mention that it produces the rich, buttery flavor. Cutting the butter into the flour using a pastry cutter, a tool made of several wires attached to a handle, enables an interaction between the gluten in the flour and the fat in the butter. As the butter is broken into little pieces, the flour coats the outside of the small cubes. Once the crust bakes, the heat of the oven causes the little molecules of water within the cubes of butter to evaporate, forming steam. This in turn creates a pocket of air in the crust, producing flaky layers.

However, a surprising trick to a flaky crust is through substituting some of the water with vodka as an ingredient. Normally, when water is added to flour, gluten develops. Overworking the dough leads to a tougher crust because of the gluten. Gluten is responsible for holding bread dough together and helping it become elastic, producing the chewy texture characteristic of bread. In contrast, piecrusts are meant to be tender, and therefore should have less levels of gluten. A nontraditional ingredient to pie crust, vodka contains 40% alcohol, which in turn prevents gluten formation. In addition to not adding a taste, as the crust is baking, the vodka evaporates much more quickly than water, preventing the crust from coming out as soggy.

Golden and delicious

The color and flavor of our pies are formed from the Maillard reaction, which occurs between the amino acids in proteins and sugar molecules. At higher temperatures, this reaction occurs faster, meaning a more browning and more flavor. Generally, temperatures of at least 375 degrees Fahrenheit produce nice browning. However, too high of a temperature and the crust will become burnt. Applying an egg wash, comprised of beaten eggs and heavy cream, will increase the amino acid and sugar content, respectively, which will increase the rate of the Maillard reaction

Before a pie enters the oven, it’s important to use a knife or fork to cut small vents into the tops of pies with another layer of crust to allow steam to escape. Particularly in apple pies, where water is released and evaporates, not having an escape hole will cause the pie to swell, eventually bursting.

As the pie bakes, the mouth-watering smell will waft around your kitchen, a good sign of success. However, as you pull it out of the oven and are met with the beautiful sight of a pie with a golden, flaky crust, you’ll know you have truly harnessed the technique of making a delicious pie.

Image courtesy of Jessica Trinh
Image courtesy of Jessica Trinh

Easy as pie

Once you realize the science behind the flaky layers, you’ll come to realize making piecrust is…as easy as pie. So if you’re bold and willing to attempt baking pies or if you know someone baking, try to keep these tips in mind. If at first you don’t succeed, pie, pie again…

 

 

 

Jessica Trinh is a freshman in Branford College. Contact her at jessica.trinh@yale.edu.

Feature Image courtesy of Wikimedia

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