How does yeast make bread rise?
YEASTS ARE THE TINY PLANTS THAT, WHN MIXED IN MOIST BREAD DOUGH, RELEASE A GAS THAT PUFFS UP THE DOUGH AND MAKE THE BREAD SOFT AND LIGHT.
Bread is the oldest of all manmade foods.
The earliest bread was not like the bread you are probably used to. It was hard, flat, and dry.
The bread that we eat most often today is leavened, or raised, with yeast to make it soft and light.
A package of yeast is really a package of tiny plants. Each yeast plant is so small that you can only see it with a microscope. One yeast plant by itself looks like a tiny potato.
Yeast plants grow rapidly when mixed in warm, moist bread dough. Little buds grow out the sides of each yeast plant. The buds are baby yeast plants.
Before long, the buds form buds of their own. As the yeast plants grow and multiply, they give off a gas called carbon dioxide. The gas bubbles pug up the bread dough.
When the bread is baked, the yeast plants are killed and the carbon dioxide gas escapes, leaving the familiar holes in bread. – Dick Rogers