The journey of sourdough bread

If you were to look inside your kitchen right now, would you be able to spot a loaf of sourdough bread? Although it may seem like an ordinary piece of bread on the outside, sourdough bread is more fascinating than you think. 

This unique form of bread dates back to approximately 1500 BCE originating in Ancient Egypt. While the discovery of this tangy bread is widely debated, it is highly believed that its invention was accidental. The most popular origin theory is that a batch of dough had been left out overnight, creating wild yeast. These microorganisms, which facilitate fermentation, then mixed in with the dough before it rose and added the signature sour flavor to the bread. Thus, sourdough bread was born and became a staple in many ancient diets.

So, what makes sourdough bread distinct from other types of bread? Sourdough is unique because it is created using yeast naturally sourced from the environment, rather than commercial yeast which is cultivated in factories. Bread made with commercial yeast generally tends to be less flavorful, which explains why sourdough is objectively tastier than other types of bread. 

The first step in creating sourdough is producing a starter. A starter for sourdough bread is a mixture of flour and water that consists of wild yeast and bacteria. After mixing flour and water, the mixture is left out for approximately a week, giving a chance for the yeast to be collected from the air. The yeast in the mixture then starts a process called fermentation, which is the cycle of generating adenosine triphosphate (ATP), energy, without oxygen. The tiny organisms consume the sugars in the starter, allowing fermentation to take place. The cycle contributes to the tartness of the bread.

Additionally, the lactic acid bacteria in the air also enter the starter and begins to perform fermentation. While the yeast ferments the sourdough starter, the yeast releases byproducts into the mixture which include carbon dioxide and ethanol. Carbon dioxide causes the dough to rise and dilate, while ethanol partly contributes to the bread’s flavor. Lactic acid bacteria, however, produce different byproducts which mainly include lactic and acetic acid. While the lactic acid is responsible for the sourdough bread’s tanginess, the acetic acid accounts for its sour taste.

Sourdough bread offers a variety of health benefits, one of the primary ones being that it has a lower glycemic index compared to white bread. As a result, sourdough bread allows for a steadier increase in blood sugar and insulin levels, helping people who consume it to maintain better energy levels throughout the day. Moreover, sourdough bread supports gut health and digestion within the body. Due to fermentation, sourdough contains both prebiotics and postbiotics which help feed the good bacteria in our stomachs. 

Today, sourdough bread has flourished from its ancient beginnings, becoming a staple in many parts of the world. Sourdough bread has found its place in France, Italy, Switzerland, Denmark, Germany, and most famously, in our own backyard in San Francisco! While it’s best known for its unique, tangy taste, sourdough bread also reserves its place as an edible documentation of history. So, the next time you’re at your local grocery store or your favorite bakery, don’t be afraid to give sourdough bread a try!