Hi Lisa! Introducing ice cubes or drinking water in your oven can definitely help with crust progress (especially when baking sourdoughs!). Though It's not necessarily Certainly required, it may also help build a lovely loaf. Here's a little bit more information on the process: Baking bread with steam Delighted Baking! https://judahwrjct.blogdiloz.com/27722380/indicators-on-sourdough-in-a-loaf-pan-you-should-know