The best sourdough starter I have ever used was made with green grapes. The natural yeast in the air and the sugar in the grapes produces the perfect super-sour-sponge, just like they make in San Francisco. Its so easy and fast to make this starter for bread, pancakes, and crepes. Simply wash and stem 1-pound of seedless green grapes, crush the grapes with a potato masher and place in a bowl. Cover with a muslin cloth or cheesecloth and let set on your kitchen counter for 2 days. Strain the liquid into a 2-cup measuring cup and add water up to the 2-cup level. Add 1-cup of flour and 1-cup of luke-warm water. Mix with a wooden spoon, pour into a quart jar or a large container with a lid. Loosely cover container with the lid and set out on kitchen counter for 24 hours. Feed the sponge again with 1-cup of flour and 1-cup of luke-warm milk (1%, 2% or whole milk is fine) and let set for another 24 hours. If the sponge is bubbly, its ready to use in your favorite recipe.
- Replace the sponge used with same amount of flour and water. If your recipe calls for 1 cup of starter. Add 1 cup flour and 1 cup water or milk to the remaining starter and let set in a warm place for 24 hours.
- Feed your sponge at least once a week. Remove a cup of starter and replace with 1-cup flour and 1-cup luke-warm water or milk.
- Refrigerate if not using sponge within 24 hours of feeding.
Watch this video recipe from Harvest Eating: Sourdough Crepes