Why Bread has Holes and Grows Mold
Yeast
The most fundamental biological process in bread making is fermentation, initiated and sustained by the life activities of a unicellular plant; a microscopic yeast cell. Baker's yeast belongs to the Sacchromyces cervisiae species and is actually a member of the mushroom family. It is a biological leavening agent and possesses the basic attributes of all living things, which are respiration and reproduction. Its role in bread making is to convert sugars to carbon dioxide gas and thus leaven the dough. Yeast is the little "artisan" who creates the internal cellular structure of bread. Yeast fermentation is also involved in the maturation of the dough and, like wine or beer, contributes greatly to the production of bread taste. The following are some valuable links to information on the web concerning yeast:
The Science of Yeast
Bacteria
Bacteria also contributes either positively or negatively to the overall quality of the finished loaf. In sourdough bread, bacterial cultures are categorized under the rather poorly defined "wild yeast" category. This is in reference to ambient yeast and bacterial microorganisms already present in the flour, water, air, on your hands and anything else that comes into contact with the dough. Bacterial growth, like yeast, is affected by moisture, ph, temperature, food supply, salt, sugar, oxygen supply and light. Most bacteria grow well in moist environments with temperatures ranging between 25-40C. However, some like it colder (just over freezing) and some like it hot (60-80C). Bacteria thrive at a pH around neutrality (6.5- 8.0). Most chemicals will kill bacteria. Since bacteria will not grow in mediums with large amounts of salt, salt plays a contributing factor to the leavening of sourdough bread. It is important to note that not all bacteria is beneficial to bread. Some cause infections that have negative effects on the finished product. High hydration doughs are more susceptible to bacterial infections like "Ropy Bread" and the particularly interesting "Bleeding Bread"
Mold
The presence of mold in baking ingredients, equipment or products is deleterious and undesirable. Molds constitute a principal group of spoilage organisms. Most of the ingredients used in baking are subject to mold infections as well as finished loaves.
Two types of the most common molds to watch out for:
Mucor: Blueish mold.
Rhizopus: Black mold.
The most fundamental biological process in bread making is fermentation, initiated and sustained by the life activities of a unicellular plant; a microscopic yeast cell. Baker's yeast belongs to the Sacchromyces cervisiae species and is actually a member of the mushroom family. It is a biological leavening agent and possesses the basic attributes of all living things, which are respiration and reproduction. Its role in bread making is to convert sugars to carbon dioxide gas and thus leaven the dough. Yeast is the little "artisan" who creates the internal cellular structure of bread. Yeast fermentation is also involved in the maturation of the dough and, like wine or beer, contributes greatly to the production of bread taste. The following are some valuable links to information on the web concerning yeast:
The Science of Yeast
Bacteria
Bacteria also contributes either positively or negatively to the overall quality of the finished loaf. In sourdough bread, bacterial cultures are categorized under the rather poorly defined "wild yeast" category. This is in reference to ambient yeast and bacterial microorganisms already present in the flour, water, air, on your hands and anything else that comes into contact with the dough. Bacterial growth, like yeast, is affected by moisture, ph, temperature, food supply, salt, sugar, oxygen supply and light. Most bacteria grow well in moist environments with temperatures ranging between 25-40C. However, some like it colder (just over freezing) and some like it hot (60-80C). Bacteria thrive at a pH around neutrality (6.5- 8.0). Most chemicals will kill bacteria. Since bacteria will not grow in mediums with large amounts of salt, salt plays a contributing factor to the leavening of sourdough bread. It is important to note that not all bacteria is beneficial to bread. Some cause infections that have negative effects on the finished product. High hydration doughs are more susceptible to bacterial infections like "Ropy Bread" and the particularly interesting "Bleeding Bread"
Mold
The presence of mold in baking ingredients, equipment or products is deleterious and undesirable. Molds constitute a principal group of spoilage organisms. Most of the ingredients used in baking are subject to mold infections as well as finished loaves.
Two types of the most common molds to watch out for:
Mucor: Blueish mold.
Rhizopus: Black mold.
