My sourdough contains 4 simple ingredients. No preservatives. Unlike store bought, my home-baked sourdough contains no commerical yeast or flavoring syrups (vinegar, barley malt). The flavor in my sourdough comes from natural fermentation and a long cold proof before baking. There's nothing additional added to achieve the tangy flavor you love! High quality ingredients are used. It's important to me to use flour that is unbleached and contains no bromate. The flour I use is also Non-GMO Certified.