Cast Iron Bakery Sourdough is made with basic ingredients: natural yeast, quality flour, water, and sea salt. These combine to make a sourdough whose light tang and soft crumb is uniquely excellent for sandwiches, french toast, and dipping. All the bread is made in a cast iron, sandwich bread loaf form. Even though sourdough is traditionally made in the round artisan style, the sandwich loaf form makes the bread much more convenient for everyday use--and we like to use it every day!