Ask A Scientist: On Gels and Pumpkin Pie Tears
It's never too early to start your Turkey Day prep, you guys.
July 12, 2017 ● 1 min read
Q: Why does pumpkin pie sweat?
A: Gels are just liquid water trapped in nets of carbs and protein. The starch in the pumpkin and the proteins in the eggs create a pretty nice gel, but there are two ways that gel can allow water to escape.
The most common problem is probably over-cooking. As proteins get heated, they unfold from tight little balls to form fine, lacy nets that make great gels. If exposed to too much heat, those networks begin to implode, forming clustered clumps of protein, similar to cheese curds or scrambled eggs. That collapse leaves a lot of gaps for water to escape.
Even with perfect execution, some recipes yield weepy pies because they don’t have enough protein or carbs to form a sufficiently water-tight network. The old school solution is to add carbs in the form of cornstarch, but I’ve always preferred adding proteins in the form of gelatin. Gelatin gels tend to have smoother textures than starch gels, and gelatin holds onto aromas less tightly, so you will get more mileage out of your spice mix.