Simply preheat your cast iron skillet on the bottom rack of the oven before you add your sourdough. Place your bread, either on a baking stone or cookie sheet on the middle rack, and then pour boiling water into the skillet.
Pie weights are typically used to help hold the shape of your pie dough when baking it; however, pie weights work great to help create steam in an oven.
Placing a baking dish on the bottom rack, with steaming hot towels helps to create steam and hold moisture in the oven for your sourdough bread.
Preheating water in a baking dish is a quick and easy way to build steam in your oven to assist your sourdough.
Spritz water into your oven as soon as you put your bread in the oven and close the door quickly. This creates and quick and easy steam for your bread.