Here's what I do for the majority of my pies, to great success! After rolling out the chilled pie crust, I lightly brush the whole crust with an egg white, which has been whipped up lightly with a fork. Use a fine pastry brush to apply the egg white, then I sprinkle the edge with sanding sugar, and refrigerate about 15 minutes. Then put your fruit or custard filling in the pie, then into the over to bake. The egg white wash helps to seal the crust - thereby keeping it from getting soggy.