Sourdough breads are created using a sourdough starter. The starter cultivates yeast and lactobacilli in a mix of flour and water, making use of the microorganisms already existing on flour; it doesn't have to have any additional yeast. Hokkaido bread has obtained reputation throughout the world for its special texture https://foodlearningcenter48147.alltdesign.com/how-much-you-need-to-expect-you-ll-pay-for-a-good-food-51528998