What is sourdough?
Sourdough is bread made with a starter of wild yeast and bacteria instead of commercial yeast. The bacteria produce acids that give it a tangy flavor and chewy texture.
A sourdough starter is a mix of flour and water that has been left to ferment. Wild yeasts from the flour and air make it bubble and rise, while lactic acid bacteria produce lactic and acetic acids, giving the bread its sour taste. Bakers keep the starter alive by feeding it regularly with fresh flour and water, and some starters are decades old.
Making sourdough takes longer than using packaged yeast. The dough often rises slowly for many hours or overnight. This long fermentation develops flavor and can make the bread easier for some people to digest, because it breaks down some of the starches and proteins.
An ancient method
Sourdough is one of the oldest forms of leavened bread, likely used in ancient Egypt thousands of years ago. San Francisco is famous for its sourdough, which became popular during the California Gold Rush. Home sourdough baking became a worldwide trend during the COVID-19 lockdowns in 2020.
Did You Know?
Some bakers give their sourdough starters names and treat them like pets, passing them down through families.