Sourdough Starter - cooking recipe

Ingredients

1 pkg. active dry yeast
2 1/2 c. warm water
1 c. instant nonfat dry milk
2 Tbsp. sugar
4 c. flour

Preparation

Stir yeast, water, milk and sugar in 2 1/2-quart crock or other nonmetallic bowl until yeast is dissolved.
Stir in flour until a smooth batter forms.
Let stand loosely covered in a warm place for 3 to 5 days.
Stir down occasionally.
Store loosely covered in refrigerator.