Crusty Sourdough Bread | Williams Sonoma

Ingredients

• 1 cup organic grapes 
• 2 cups plus heaping 1/4 cup unbleached bread flour, plus more as needed
• Warm water (105°F), as needed
• 1 cup bubbly sourdough starter 
• 1 cup warm water (105°F)
• 4 cups unbleached bread flour, or as needed
• 2 tsp. kosher salt 
• Olive oil for bowl  
• Cornmeal or semolina flour for pan 
• 3 cups hot water