In a large mixing bowl,stir starter, water, flours, and vital wheat gluten together until combined. You will have a rough, sticky dough. Allow dough to rest for 20 minutes. Add salt and caraway seeds. Mix well. . Cover and allow it to rise for 1 hour. Remove lid and gently pick up one side of the dough, fold it in thirds. Take the opposite side and fold in thirds. Repeat with the opposite side of dough. Cover and allow to rise for another hour. Repeat 3 more times for a total of 4 folding times. Cover and place in the refrigerator for 12 hours. Remove dough from the refrigerator. Fold dough in 3rds, pinching the dough together to seal the edges. Turn dough and fold in 3rds, pinching to seal edges. Line the bottom of the clay baker with parchment paper or foil. Place loaf seam side down in a clay baker. Cover. Allow loaf to warm to room temperature for 2 hours. Preheat oven to 450 degrees F. Remove the lid from the baker and fill with water. Allow the water to soak the lid for 10 minutes. Slash the loaf with a sharp knife. Empty the water from the lid and place it on the clay baker. Place the covered baker into the hot oven. Set the timer for 35 minutes. Reduce oven temperature to 400 degrees. Remove the lid and bake for an additional 18-19 minutes. Remove clay baker from oven. Remove loaf to a wire rack to cool. 12-14 slices.