There are a number of different pastries that you might use for a pie, sweet pastry for desserts and savoury pastry for meat pies for example. In addition you could use shortcrust or flaky (puff) pastry in either situation. All of these pastries will freeze and keep well whether they have been cooked or not. In fact you can purchase very good frozen pastry in stores, and generally, I would recommend making your own shortcrust pastry, since it is simple to do, but buy pre-made flaky (sometimes known as puff) pastry unless you have a lot of time and want to put the effort into layering and folding the pastry a number of times.
Pastry is made from fat (butter, lard or a mx of the two), flour, water and seasoning. It is the fat element than you need to be most careful with when freezing. The ingredients are combined by hand until a dough is formed which is just slightly sticky to the touch and has been worked until the bowl is left clean. You can freeze the pastry from any point forward, and it will keep well. It is sometimes best to shape the pastry into a pie crust before, and I would suggest the following rules of thumb.
Assuming you are starting with fresh pastry, either homemade or shop bought, the first thing you need to decide is whether or not you will want to cook the pastry from frozen or whether you are going to defrost the pastry. If you are going to cook from frozen then you should roll and shape the pastry before freezing. If you are going to defrost the pastry before use, then you may roll and shape before freezing or you might decide to roll the pastry after it has been defrosted. This same process needs to be considered with regarding to freezing the pastry as raw or cooked. If freezing cooked pastry, then it too should be rolled and shaped before freezing, in fact you may wish to freeze it in it’s own baking tin. If freezing raw pastry, then you can decide when to roll the pastry to best suit your needs.
To freeze a pie crust if you have cooked the pastry first, let it cool down to room temperature before freezing.
When you have the pastry ready to freeze, wrap it in clingfilm. This should be done in appropriate portion sizes or as individual pie crusts if pre-shaped. The pastry can be placed in the quick freeze compartment of your freezer until frozen. Then transferred to the normal freezer compartment. I wouldn’t keep frozen pastry more than about six months, although I believe it can be kept frozen for longer.