In apple pie, what crust may be baked separately first to prevent sogginess?

In apple pie, the bottom crust may be baked separately first to prevent sogginess.

This technique is called blind-baking, or prebaking, and it firms the pastry before the wet apple filling is added. The crust is commonly lined with parchment and weighed down with pie weights, dried beans, or rice so it keeps its shape while baking.

Apple filling releases moisture as fruit heats and sugar draws out liquid. If raw pastry sits beneath that filling for the entire bake, the base can remain soft even while the top is browned. Prebaking gives the bottom a head start and helps produce a crisper slice.

The answer is not the upper crust: a top crust may be solid or latticed, but it does not line the pan beneath the filling. Blind-baking is especially associated with pies whose fillings are very wet or are added after the crust is fully baked; apple pies vary, so recipes differ on whether the base is partially or fully prebaked.