Sourdough Biscuits
["1 pkg. dry yeast", "1 c. warm water", "7 c. self-rising flour", "1/4 c. sugar", "1/2 c. shortening (Crisco)", "2 c. sour milk"]
["To sour milk, add 2 tablespoons vinegar to 1 pint sweet milk."]
["yeast", "water", "flour", "sugar", "shortening", "sour milk"]