PreparationFor crust: Stir together yeast, wine, honey, and warm water in a large bowl until yeast is dissolved. Let stand until bubbly, about 10 minutes. Stir in 1 cup flour (mixture will be lumpy). Cover bowl with plastic wrap and a kitchen towel and let rise in a warm place until doubled in bulk, 40 to 50 minutes. Add oil, 1 1/2 cups flour, and sea salt and stir until a sticky dough forms. Knead dough on a floured work surface, gradually adding up to 1/2 cup more flour if necessary to keep dough from sticking, until dough is smooth and elastic but still soft, 8 to 10 minutes. Transfer dough to an oiled large bowl and turn to coat. Cover bowl with plastic wrap and a kitchen towel and let rise in a warm place until doubled in bulk, about 1 hour. Turn out dough onto work surface and knead several times to release air. Cut dough in half. Roll out 1 piece of dough, keeping remaining piece covered, with a lightly floured rolling pin into a rough 12- by 10-inch rectangle. Transfer dough to a lightly oiled 15- by 10- by 1-inch baking pan and gently stretch to cover as much as possible of bottom (dough may not fit exactly). Scatter half of grapes over dough, then sprinkle grapes with 1/4 cup sugar. Roll out remaining piece of dough in same manner and put on top of grapes, gently stretching dough to cover grapes. Scatter remaining grapes and 1/4 cup sugar on top and gently press into dough. Cover pan with plastic wrap and a kitchen towel and let rise in a warm place until doubled in bulk, about 1 hour. Preheat oven to 400°F. Bake schiacciata in middle of oven until well browned and firm in middle, 40 to 45 minutes. Loosen sides and bottom of schiacciata with a spatula and slide onto a rack to cool. Serve at room temperature. Cooks' note:• Wine and Concord grapes are delicious, but they do have large pits compared to other grape varieties. Resist the temptation to pit them—it's difficult to do and too much liquid will exude from them into the dough.
PreparationFor crust: Stir together yeast, wine, honey, and warm water in a large bowl until yeast is dissolved. Let stand until bubbly, about 10 minutes. Stir in 1 cup flour (mixture will be lumpy). Cover bowl with plastic wrap and a kitchen towel and let rise in a warm place until doubled in bulk, 40 to 50 minutes. Add oil, 1 1/2 cups flour, and sea salt and stir until a sticky dough forms. Knead dough on a floured work surface, gradually adding up to 1/2 cup more flour if necessary to keep dough from sticking, until dough is smooth and elastic but still soft, 8 to 10 minutes. Transfer dough to an oiled large bowl and turn to coat. Cover bowl with plastic wrap and a kitchen towel and let rise in a warm place until doubled in bulk, about 1 hour. Turn out dough onto work surface and knead several times to release air. Cut dough in half. Roll out 1 piece of dough, keeping remaining piece covered, with a lightly floured rolling pin into a rough 12- by 10-inch rectangle. Transfer dough to a lightly oiled 15- by 10- by 1-inch baking pan and gently stretch to cover as much as possible of bottom (dough may not fit exactly). Scatter half of grapes over dough, then sprinkle grapes with 1/4 cup sugar. Roll out remaining piece of dough in same manner and put on top of grapes, gently stretching dough to cover grapes. Scatter remaining grapes and 1/4 cup sugar on top and gently press into dough. Cover pan with plastic wrap and a kitchen towel and let rise in a warm place until doubled in bulk, about 1 hour. Preheat oven to 400°F. Bake schiacciata in middle of oven until well browned and firm in middle, 40 to 45 minutes. Loosen sides and bottom of schiacciata with a spatula and slide onto a rack to cool. Serve at room temperature. Cooks' note:• Wine and Concord grapes are delicious, but they do have large pits compared to other grape varieties. Resist the temptation to pit them—it's difficult to do and too much liquid will exude from them into the dough.