I made this Oat Porridge sourdough with yeast water recently. The steel cut oats were cooked in milk for breakfast, and a few days later I used the leftovers for a sourdough.
Here’s the formula. It was a pretty wet dough. Two loaves.
900g flour (700 bread, 200 whole grain turkey red)
710g water (460 regular, 250 fruit yeast water)
300g steel cut oat porridge
160g sourdough starter
1.5 tsp salt