What makes Boudin sourdough sour?

The secret is in our starter, or mother dough, which includes micro-organisms that slowly and naturally ferment and raise the bread, producing a deliciously sour flavor. Our starter is proprietary, as it is the original mother dough from 1849, so we do not share or sell it. We don’t make an extra sour version of our bread, either, as we prefer to use the original Sourdough French Bread recipe.