Bride's Biscuits

1 package dry yeast
1/2 cup warm water
5 cups flour
3 tablespoons sugar
1 tablespoon baking powder
1 teaspoon baking soda
1 teaspoon salt
1 cup shortening or butter
2 cups buttermilk

Dissolve yeast in warm water. Let stand 10 minutes. Sift flour, sugar, baking powder, baking soda, and salt into a large bowl. Cut in the shortening or butter with a pastry cutter or two knives. Combine buttermilk and dissolved yeast. Stir into dry mixture, working only until moistened. Put in a large, plastic, container. Cover and refrigerate several hours before baking. Dough can be stored in refrigerator for up to one week. Carefully roll out on a well-floured surface half-inch thick. Cut with a 2 1/2 inch biscuit cutter. Place on greased baking sheet. Bake at 400 degrees for about 15 minutes or until golden. Makes 3 dozen biscuits.