I must admit I have issues with my pie crust shrinking. I rarely have this problem with Krusteaz pie crust, but if I venture out to make one from scratch I have an issue every single time. I have read countless articles about pie shrinkage, but after a while the articles keep repeating themselves. I would consider these the top 5 repeats.
Before you read on, one quick solution might be to add baking powder to your dough. Baking powder causes the crust to expand as it bakes and doesn’t really change the flavor of your dough. I would recommend adding 1/4 tsp to your pie dough.
1. Avoid glass pans if possible
Glass pans are much more slippery than their metal or ceramic counterparts. They are perfect for graham cracker crusts and other crusts that do not require baking. But if possible, I recommend using metal or ceramic pie plates when baking pies with butter pie crusts. I do not recommend spraying with nonstick spray (which is my thing).
2. Don’t overwork the dough
A big rule of thumb when making pie crusts. (Especially if you use a food processor!) Try hard to only mix the dough as much as needed to get it to stick together. It’s ok if there are still a few tiny chunks of butter or fat visible. You just want to avoid overworking the dough as this causes it to get overly firm and also shrink.
3. Don’t stretch the dough to fit the pie pan
If you stretch the dough, it will stretch back while baking. So when you roll out the dough, be sure that it is large enough to drape into your pie plate and cover it without stretching.
4. Leave a little room around the edges
I always recommend that people make their pie crusts slightly larger than you hope that they will look when baked. As in, give an extra 1/2-inch of so around the edge of the pie plate so that it has room to shrink very slightly while baking.
5. Use low baking temperatures if possible
Higher temperatures make the gluten in pie crusts tighten up and shrink a bit. So if your recipe requires pre-baking the pie crust, it will shrink less if you bake it “low and slow” (around 350 degrees F).
Adapted from http://www.gimmesomeoven.com/how-to-keep-pie-crust-from-shrinking/