Line of Sourdough Which is Sourdough? Which is Sourdough? Sourdough is a dough fermented in a culture of lactobacillus and bacteria in symbiotic combination with yeast. Allows differentiated aromas, flavors and coloring through unique raw materials:FlourStatusWheat germspelled flourBarleyQuinoagrape seedOatmealRye flour See our Sourdough ranges See our Sourdough ranges