十万个为什么·科学启蒙30篇（3）

24 / 30

酵母吃掉糖，制造微小气孔，面包就松软

Bakers mix yeast with flour, water, and sugar to start making bread dough.
Yeast is a living fungus that feeds on sugar and releases carbon dioxide gas.
Those invisible bubbles get trapped inside the stretchy gluten network of the dough.
As the dough rises, it grows puffy and full of tiny round air spaces.
Baking in the oven kills the yeast but sets the shape and locks in the holes.
That’s why fresh bread feels soft, springy, and full of little pockets when you tear it.
Too much yeast or too warm a room can make dough rise too fast and collapse.
Adding salt slows yeast down just enough to build better flavor and texture.
You can hear faint popping sounds if you tap risen dough gently before baking.
Next time you eat toast, notice how light and airy each slice feels inside.