Dissolve yeast in 1/4 Cup warm water. Add sugar, vinegar, salt and all purpose flour. Add remaining water and stir until a creamy batter if formed. Place in a glass bowl and let sit until it begins to ferment. (About 3 days) It will take on a powerful boozy smell. Stir again until creamy and measure out what is called for in your recipe.
Replenish starter with equal amounts of flour and water.
May be stored in refrigerator after 3rd day of fermentation but remove from refrigerator and bring to room temperature before using.
The original recipes says to allow to ferment for one week between uses, but I don't. I do let it sit out overnight after I feed it.