Buttermilk Biscuits

4 cups all purpose flour
1 tablespoon salt
1 tablespoon baking powder
2 teaspoons baking soda
1 cup vegetable shortening, cold, cut into ½ inch pieces
1 ½ to 2 cups buttermilk, plus additional for brushing

1. Preheat the oven to 375 degrees F.
2. Sift together the flour, salt, baking powder, and baking soda. Cut in the shortening using a pastry blender or your hands until the mixture resembles coarse crumbs. Make a well in the center and add 1 cup buttermilk. Using your hands, quickly fold the dry ingredients into the buttermilk until a sticky dough forms. You may need to add more buttermilk.
3. Turn the dough out onto a floured surface. Gently fold the dough over itself 3 or 4 times to create layers. Press the dough out to 1 ½ inches thick and cut with a floured 3 inch biscuit cutter. Lay the biscuits on an ungreased cookie sheet and brush the tops with buttermilk.
4. Bake for 20 to 25 minutes until risen and golden brown.