Sourdough Starter - cooking recipe

Ingredients

1 pkg. dry yeast
2 c. warm water
2 c. flour
3/4 c. sugar
3 Tbsp. instant potatoes
1 c. warm water

Preparation

Mix well and let stand out of refrigerator all day, 8 to 10 hours.
This does not rise, only makes bubbles.
Take out 1 cup to make bread.
Return the rest to refrigerator.
Keep in refrigerator for 3 to 5 days.
Repeat step 2.
Each time must feed and must remove 1 cup of the starter.
Keep covered in refrigerator only leave one corner of cover up.
I use foil and bend one corner back.