San Francisco Sourdough Bread

Instructions

To make the starter, mash the grapes thoroughly and put them in a loosely covered container. Leave it at room temperature for 48 hours, then strain off the fermented juice and discard the pulp.

Add warm water to the juice to make 1 pint (450 ml), stir in the bread flour, and leave it at room temperature overnight. To keep the starter going, feed it 1 pint of warm water and 2 cups of flour daily if it stays at room temperature, or twice a week if you refrigerate it.

For the dough, sprinkle the dry yeast over 4 tablespoons of the warm water in a glass measuring cup. Let it stand until foamy. In a bowl, combine the rest of the warm water with the sourdough starter.

Stir 1 cup of the flour into the starter mixture until a dough begins to form, then add the foamy yeast and mix for 5 minutes. Add the remaining flour and the salt, and knead for 10 minutes or more, until the dough is soft and elastic.

Put the dough in a greased bowl, cover it with a damp cloth, and let it rise in a warm place, about 80°F (27°C) to 90°F (32°C), until doubled in size.

Punch the dough down and shape it into a round loaf. Set it on a greased, cornmeal-dusted sheet pan, cover with a damp cloth, and let it rise in a warm place until doubled again.

Brush the loaf with beaten egg white and score the top in a criss-cross pattern with a sharp knife. Bake at 450°F (230°C) for 10 minutes with a pan of boiling water on the rack below.

Reduce the oven to 375°F (190°C), take out the water, and keep baking for about 35 to 45 minutes, until the loaf is well browned. Cool it on a rack.