Baking Sourdough Bread | St. Lawrence University Sustainability Program

Baking Sourdough Bread

Saturday, October 7, 2017

Original recipes of bread include only a handful of very basic ingredients: flour, water, sourdough culture, and salt. The sourdough culture is responsible for the transformation of a flour and water mix to a real dough to bake fresh bread. This conversion is made possible by bacteria called Lactobacillus which converts the flour, carbohydrates, to lactic acid. The lactic acid creates the sour flavor but it also produces carbon dioxide gas which forms gas bubbles. The gas bubbles let the dough rise and is responsible for the soft consistency of our bread. Without a rising agent such as yeast, baking powder or sourdough our baked goods would be rock hard. Sourdough culture contains the necessary bacteria and is, therefore, the key component to bake a good bread.

The sourdough culture must be cultivated from naturally occurring bacteria. Other than yeast bacteria it cannot be bought in freeze dried form. I cultivated the culture by mixing water and flour and kept feeding it again with water and flour for several days until the distinct sour smell and gas bubbles were in the starter. Then the starter is ready to be mixed with the flour and water for actual bread baking. In around half a day later the bacteria have spread throughout the dough. Now the final ingredients, like salt and flax seeds, can be added. Then the bread needs to rise in its final shape for another hour and can be baked. Since the process is centered around the bacteria culture, it is important to keep it alive and ready for the next time backing bread. For this, some dough needs to be put in the fridge where it can store for a week. During the baking itself, the bacteria dies from the high temperature and stops the fermentation making the bread storable.

Baking and cultivating fermentation cultures has part of human cultures and can be traced back to early civilizations. It has been a part of human culture and daily life until food processing was industrialized. Nowadays, baked goods are often packed and not fresh, so baking them yourself provides an experience of this lost culture.