This is an example of using another substance along with flour to inoculate a starter with natural yeast that live on the surface of fruit or vegetables in the hopes that they will attract related yeast that can effectively leaven bread dough.  It is an early version of Nancy Silverton's famous Grape Starter that she shared with Julia Child.
 
 

EQUIPMENT NEEDED:
A 2 quart glass container
1 yard washed and well-rinsed cheesecloth

STARTER INGREDIENTS:
2 cups bread flour
2 1/2 cups 70 degree F water
1/2 pound stemmed red grapes (preferably organic)
 

Stir the flour and water together in the container, mixing well, don't worry about lumps.  Lay the grapes on a double layer of the washed cheesecloth and tie opposite corners together to form a bag.  Lightly crush the grapes with a rolling pin, then swish the bag through the flour/water mixture and submerge.  Cover tightly with a lid or with plastic wrap and an elastic.  Leave at room temperature for six days, stirring it up once a day.

The bag of grapes will gradually appear inflated, and liquid will begin to separate from the flour base.

The mixture will begin to taste and smell slightly fruity, and the color will be strange. That is as it should be.  By the sixth day, the bag of grapes will have deflated, the color will be yellow, and the taste pleasantly sour: the fermentation is complete.  The starter is living, but weak, and it needs to be fed.

Lift out the bag of grapes and squeeze their juices back into the starter, then discard the grapes.  Stir up the starter throughly, transfer it into a clean container.  (Although you can use it after just one feeding, the starter will be stronger and healthier with the full treatment.)
 
 

FEEDING INGREDIENTS:
3 cups bread flour
3 cups tepid water

Three days before you plan to use it, stir one cup of flour and one cup of water into the container, blending well.  Let stand uncovered at room temperature until it bubbles up, 3 or 4 hours, then cover and refrigerate.  Repeat the feeding the second day, and again on the third, and your starter is ready to use.

The starter will keep for 4 to 6 months in the refrigerator between feedings.  Before using the stored starter for bread, give it the full 3 day feeding schedule once again to strengthen it and to tone down excess sourness. "
 
 

Follow your recipes instructions for incorporating the starter into bread dough.
 
 

See Starter Maintenance if your starter is ailing or you need more information on maintaining your starter, .

See Baking with a starter for some recipes and tips on finding other great sourdough recipes.

See Sourdough Definitions for help in understanding some sourdough technical terms.
 
 
 
 

Credits:
From  "Cooking With Master Chefs" by Julia Child, as posted to Rec.Food.Sourdough November, 1994.