There are different agents used to make bread, thereby resulting in a variety of characteristics and properties. The yeast does not produce the sour taste of sourdough. It is actually lactobacillus, wherein the yeast lives in symbiosis. The lactobacillus feeds on end-products of yeast fermentation, in turn, creating the culture that goes sour through the excretion of lactic acid. This protects everything from spoiling.
All bread before were sourdoughs, and the leavening process was not fully known until the 19th century. Only with the development of microscopes did scientists find out that dough can rise through microbes. The strains of yeast have been chosen and packed as Baker's Yeast. Bread created using Baker's yeast is not sour due to the absence of the lactobacillus. The yeast was then embraced by bakers all over the globe.
More on Sourdough Bread
Sourdough bread is usually made using a sourdough starter. A sourdough starter is a culture of lactobacillus and yeast. It is a pancake-like flour and water mixture wherein the lactobacilli and yeast live. A starter can be managed nonstop by regularly eliminating a part then refreshing by adding water and fresh flour. There are starters owned by families and bakers that are many generations old. Starters can be acquired by getting a piece of starter and growing it. These can also be made from nothing. There are groups online who can send you starters. Other companies also can send you starters through mail order.
Other procedures can also be done to bake and culture sourdough. A more traditional approach is the process followed by peasant families all over Europe in the past. The family usually bakes on a regular basis, like once a week. The starter is saved from the dough made the previous week. The starter is then mixed using the new ingredients, and the dough left to rise. A piece of it will be saved to become the starter for the following week. The others are formed into loaves and marked with the family sign. The communal ovens will evolve into bakeries, with people beginning to specialize in bread baking.
On Bread Bacteria
Salt-risen bread uses a type of bacterial leavening that does not need yeast. Even though the leavening action is not consistent and needs close attention to the incubating conditions, the bread is become more common because of its special cheese-like flavor and smooth texture.
Fats and Preparation
Fats like vegetable oils, butter and lard can change the gluten development in bread by lubricating and coating the single protein strands and helping in holding the structure together. If there is too much fat inside the bread dough, the lubricating effect usually leads the protein structures to separate. The greatest leavening action is achieved by using the fat content of 3% by weight.
Bread preparation among cultures will vary. The crusts, body, and texture will change depending on the ingredients used and the methods incorporated. Some bakers will use special personalized methods to give it a sense of originality that no other can copy.