Hi Lisa! Incorporating ice cubes or h2o towards your oven can really help with crust improvement (especially when baking sourdoughs!). When It's not at all Totally needed, it will help create a wonderful loaf. Here's a tad more info on the process: Baking bread with steam Joyful Baking! Take note: https://rowanikljh.shotblogs.com/the-smart-trick-of-sourdough-bagels-that-no-one-is-discussing-42299790