Mix yeast, sugar and the 1/2 cup water. Then, mix in flour and 2 cups water. Store in glass jar covered with cloth fastened with rubber band. Keep at room temperature for 5 days. It should bubble and have yeasty aroma. Feed with the following and store in refrigerator. 1 c. warm water 3 tbsp. instant potatoes
You can take out a cupful to make bread anytime as long as it reaches room temperature first. The Potato flake bread recipe was the same as Sour Dough except 1/2 cup sugar instead of 1/4 cup. Use sour dough bread recipe following.