When professionals make artisanal sourdough bread, they typically use a technique called "retarding" or "cold fermentation" to achieve a slow rise overnight. This process allows the dough to develop flavor and texture while slowing down the fermentation process.
Here's a general outline of the steps professionals may follow:
Mixing the dough: Professionals start by mixing flour, water, and a sourdough starter (a fermented mixture of flour and water that contains wild yeast and bacteria). The dough is usually mixed until it reaches a shaggy consistency, then left to rest for a period of time.
Bulk fermentation: After the initial mixing, the dough undergoes a period of bulk fermentation. During this phase, the dough is left at room temperature for several hours (typically 2-4 hours) to allow the yeast and bacteria to develop, and the gluten in the dough to strengthen. This process helps to develop flavor and structure.
Shaping the loaves: Once the bulk fermentation is complete, the dough is divided into individual portions and shaped into loaves. This can be done by gently stretching and folding the dough, creating tension on the surface to give the loaf structure.
Cold fermentation (retarding): After shaping, the loaves are placed in a cool environment such as a refrigerator, where they can rise slowly overnight. The cooler temperature slows down the activity of the yeast, allowing the flavors to develop and creating a more complex taste. This process also helps improve the texture of the bread.
Baking: The next day, when the loaves have had sufficient time to rise and develop flavor, they are taken out of the refrigerator and allowed to come to room temperature for a short period. This step ensures that the dough is not too cold when it goes into the oven, allowing for proper oven spring and an even bake.
Preheating the oven: Meanwhile, the oven is preheated to a high temperature (usually around 450-500°F or 230-260°C) to create a hot environment for baking the bread.
Scoring and baking: Just before baking, the loaves are scored with a sharp knife or razor blade. This helps control the expansion of the bread and creates an attractive pattern on the surface. The loaves are then placed in the preheated oven and baked until they reach the desired level of crust coloration and internal temperature.
By using the process of cold fermentation, professionals can produce flavorful and well-structured sourdough loaves with a slow rise overnight, ready to be baked all at once for sale the next day.