Was this supposed to be baked in loaf pans? I’m not 100% sure about that because I was going off limited information and ended up just doing what was easiest for me at the moment. My light research showed bread like this that uses both dried yeast and sourdough starter baked in a loaf pan as a sort of “cheater” sourdough since it doesn’t require as much fuss as traditional sourdough. This could also be referred to as a discard recipe for your starter since it’s not relying on only that natural leavening to get the bread its rise.
1c Sourdough starter
1 packet of yeast, about 2 1/4 tsp
1 1/2c slightly warm water
5c all purpose flour
2 Tbsp sugar
1/2tsp baking soda
1/2 tsp salt
In a large bowl combine the water, yeast, and sugar. Let the mix rest for 5 minutes to activate the yeast. Add in the sourdough starter, 4c flour, and salt, mixing until thoroughly combined. Let rise until doubled. In a small bowl whisk together 1c flour and the baking soda. After the first rise add-in the flour/baking soda mixture and knead until the dough is smooth and springy. If the dough is too wet add a tablespoon of flour at a time until it’s not super sticky. Divide dough into two loaves and place in loaf pans. Let rise until the dough is about 1 inch taller than the rim of your loaf pan. Bake at 400F for 40-45 minutes or until the internal temperature of your bread is 190-200F.