Published November 1, 2007. From Cook's Illustrated.

What’s the best way to store leftover cream or fruit pies?

Because of their high dairy content, leftover custard- and cream-filled pies (including pumpkin) must be wrapped tightly in plastic wrap and stored in the refrigerator. They will generally last for a day or two stored this way. Whipped cream-topped pies do not store well, because the whipped cream breaks down and begins to weep after a short period of time. If you're planning on serving only a few slices from a whipped cream-topped pie, top each slice individually with whipped cream and save the rest of the pie for later.

Double-crust and lattice-topped fruit pies such as apple, peach, blueberry, or cherry can safely be stored at room temperature because of their high sugar content and acidity, which retard the growth of bacteria. To find out if fruit pies fare better when refrigerated or stored at room temperature, we held a baking marathon, then stored pies both ways. In all cases, refrigeration turned the crisp crusts on fruit pies gummy. This occurs as a result of retrogradation, or the process by which the structure of the starch changes and becomes stale. So when it comes to fruit pies, room temperature is the way to go. Wrapped well in foil and stored at room temperature, pies made with cooked fruit will last up to two days.

Note that pies made with fresh, uncooked fruit such as strawberries are a different story. These delicate pies often contain gelatin and should be stored in the refrigerator for up to one day.

Freezing Pies

For longer-term storage options, we tested freezing two common holiday pies.. Apple pie can be fully assembled and frozen before baking, though the crust will be slightly less crisp once baked. To freeze, follow the recipe all the way through sealing the pie crust, but do not brush with egg wash. Freeze the pie for two to three hours, then wrap it tightly in a double layer of plastic wrap, followed by a layer of foil, and return it to the freezer for up to one month. On serving day, brush egg wash onto the frozen pie, sprinkle it with sugar, and bake it for 10 minutes longer than specified in the recipe. 

Pecan pie can also be frozen for up to one month before baking. Fill the pie, then wrap it and freeze it using the same method as the apple pie and bake it straight from the freezer, adding 30 minutes to the baking time. (This pie is denser than apple pie and requires more time to cook through.)

That's really useful Pamela.

I had a feeling the fridge wasn't doing the pies any good.

So it's cover with foil  at room temperature. Pat.