Pies                               Table from Professional Baking 4th Edition by Wayne Gisslen

Problem

Causes

Crust

Dough too stiff

Not enough shortening
Not enough liquid
Flour too strong

Tough

Overmixing
Not enough shortening
Flour too strong
Too much rolling or too much scrap dough used
Too much water

Crumbly

Not enough water
Too much shortening
Improper mixing
Flour too weak

Not flaky

Not enough shortening
Shortening blended in too much
Overmixing or too much rolling
Dough or ingredients too warm

Soggy or raw bottom crust

Oven temp too low; not enough bottom heat
Filling hot when put in shell
Not baked long enough
Use of wrong dough (use a mealy dough for bottom crusts)
Not enough starch in fruit fillings

Shrinkage

Dough overworked
Not enough shortening
Flour too strong
Too much water
Dough stretched when put in pans
Dough not rested

Filling

Filling boils out

No steam vents in top crust
Top crust not sealed to bottom crust at edges
Oven temp too low
Fruit too acidic
Filling hot when put in shell
Not enough starch in filling
Too much filling

Curdling of custard or soft fillings

Overbaked