1 lb (450 g) grapes, stemmed
12 oz (340 g) bread flour
Water, as needed
8½ oz (225 ml) water, warm (120°F / 49°C)
½ oz (15 g) active dry yeast
1 cup (225 ml) sourdough starter
1 lb (450 g) flour
1 Tbsp (15 ml) salt
1 egg white, beaten
Mash the grapes thoroughly and place in a loosely-covered container. Allow to stand at room temperature for 48 hours.
48 hours
Strain off the fermented juice and discard the pulp.
Add warm water to the juice to make 1 pint (450 ml).
Stir in the flour, and leave at room temperature overnight.
Replenish with 1 pint of warm water and 2 cups of flour daily if the starter is kept at room temperature. If refrigerated, replenish twice a week.
In a glass measuring cup, sprinkle the dry yeast onto the surface of 4 tablespoons of the warm water and allow to stand until it becomes foamy.
In a bowl, combine the rest of the water with the sourdough starter.
Add 1 cup of the flour. Stir until the dough starts to form and then add the yeast mixture. Mix for 5 minutes.
5 minutes
Add the remaining flour and the salt. Knead the dough until it is soft and elastic, 10 minutes or more.
10 minutes
Place the dough in a greased bowl and cover with a damp cloth. Let rise in a warm place (ca. 80°F/27°C to 90°F/32°C) until doubled.
Punch down the dough and shape it into a round loaf. Place the loaf on a greased and cornmeal-dusted sheet pan.
Let the loaf rise in a warm place, covered with a damp cloth, until it has doubled in size.
Brush the loaf with beaten egg white and score the top of the loaf in a criss-cross pattern with a sharp knife.
Bake at 450°F (230°C) with a pan of boiling water under the oven rack for 10 minutes.
10 minutes
Reduce the oven temperature to 375°F (190°C), remove the water and continue baking until the bread is well browned (about 35–45 minutes).
35–45 minutes
Cool on a rack.