The Greenstein's bakery standard recipe for Challah is:
1 cup whole wheat flour
2 cups bread flour
3 cups AP flour
1 teaspoon yeast
1 teaspoon salt
1/3 cup sugar
1/3 cup oil
2 cups water
This week I decided to experiment and exchange the AP flour for pastry flour.
The texture was much more crumbly but the taste was nice. I still think I prefer the AP flour.
The reason I attempted this was because I read in Gisslen's Professional Baking that bake shops don't stock AP flour but use cake, pastry and bread flours more precisely. I am now temped to think that is a bunch of hooey and AP flour is just fine.