nobody on Nostr: “All About Wild Yeast and Bacterial Fermentation: What makes sourdough different ...
“All About Wild Yeast and Bacterial Fermentation:
What makes sourdough different from regular bread? Most people think the difference is caused by a special wild yeast, but that is only part of the answer. Yes, a variety of wild-yeast strains aggregated under the name Saccharomyces exigus is used to make sourdough bread, as opposed to the S. cerevisiae strains used in regular breads. But the complex sour flavor is not created by the wild yeast. Other microorganisms, bacteria, specifically lactobacillus and aceto-bacillus, create lactic and acetic acids as they feed off the enzyme-released sugars in the dough, and these are responsible for the sour flavor. San Francisco sourdough bread, for example, has a particular type of local bacteria called Lactobacillus sanfranciscensis (what a coincidence!) that gives this bread a different quality, more sour with a thicker crust, than any other wild-yeast bread made in other parts of the world. (Note: L. sanfranciscensis exists throughout the world and shows up in other regions' sourdough breads, but just not in such abundance.)
What does the wild yeast do? Regular commercial yeast (S. cerevisiae), which is the same yeast used in beer making (which might explain why beer has been called "liquid bread"), does not like an acidic, or sour, environment. If bacterial activity creates too much acid, this type of yeast will die and make the bread taste funny, with an ammonia-like aftertaste and a weakened gluten structure caused by the glutathione released by the yeast. Most regular
S. cerevisiae-leavened breads have a pH level of 5.0 to 5.5.
On the other hand, wild yeast (S. exiguus) likes acidic environments (pH of 3.5 to 4.0) and therefore thrives when bacteria do their work creating lactic and acetic acids. Since it takes about twice as long for the bacteria to create flavor as it takes for the yeast to leaven the dough, it requires a hearty strain of yeast to endure. This is why wild yeast is required to make good sourdough bread.
How do you make or grow wild yeast? We do not have to make it since it already lives all around us in the air and on plants, grains, and fruits (it's in the white powdery "bloom" found on the skin of grapes, plums, and wheat berries). We do need, however, to capture and cultivate it to make bread. We do this by making a sourdough starter or what some bakers call a barm or a levain. A good bread baker knows how to keep the starter alive and healthy
of the craft of baking.
from batch to batch and how to add just the right amount to make a tasty bread. This is part of the craft of baking”
Excerpt from “The Bread Baker’s Apprentice” by Peter Reinhart
What makes sourdough different from regular bread? Most people think the difference is caused by a special wild yeast, but that is only part of the answer. Yes, a variety of wild-yeast strains aggregated under the name Saccharomyces exigus is used to make sourdough bread, as opposed to the S. cerevisiae strains used in regular breads. But the complex sour flavor is not created by the wild yeast. Other microorganisms, bacteria, specifically lactobacillus and aceto-bacillus, create lactic and acetic acids as they feed off the enzyme-released sugars in the dough, and these are responsible for the sour flavor. San Francisco sourdough bread, for example, has a particular type of local bacteria called Lactobacillus sanfranciscensis (what a coincidence!) that gives this bread a different quality, more sour with a thicker crust, than any other wild-yeast bread made in other parts of the world. (Note: L. sanfranciscensis exists throughout the world and shows up in other regions' sourdough breads, but just not in such abundance.)
What does the wild yeast do? Regular commercial yeast (S. cerevisiae), which is the same yeast used in beer making (which might explain why beer has been called "liquid bread"), does not like an acidic, or sour, environment. If bacterial activity creates too much acid, this type of yeast will die and make the bread taste funny, with an ammonia-like aftertaste and a weakened gluten structure caused by the glutathione released by the yeast. Most regular
S. cerevisiae-leavened breads have a pH level of 5.0 to 5.5.
On the other hand, wild yeast (S. exiguus) likes acidic environments (pH of 3.5 to 4.0) and therefore thrives when bacteria do their work creating lactic and acetic acids. Since it takes about twice as long for the bacteria to create flavor as it takes for the yeast to leaven the dough, it requires a hearty strain of yeast to endure. This is why wild yeast is required to make good sourdough bread.
How do you make or grow wild yeast? We do not have to make it since it already lives all around us in the air and on plants, grains, and fruits (it's in the white powdery "bloom" found on the skin of grapes, plums, and wheat berries). We do need, however, to capture and cultivate it to make bread. We do this by making a sourdough starter or what some bakers call a barm or a levain. A good bread baker knows how to keep the starter alive and healthy
of the craft of baking.
from batch to batch and how to add just the right amount to make a tasty bread. This is part of the craft of baking”
Excerpt from “The Bread Baker’s Apprentice” by Peter Reinhart