The crumb

30% whole wheat, the rest strong white flour. 70% hydration, no mixer just stretch & fold 5 times 30 minutes apart, rest until puffy, split into loaves and rest overnight in lined baskets, covered with plastic bags, in the fridge.

Bake next day in hot cast iron (you can see it in the picture) this time 450F for 20 minutes closed then 30 minutes open.

This (or slight variations) is the bread my kids call THE Sourdough.