Why does yeast make bread dough rise?

Answer 1

What is yeast?

Yeast is a tiny plant-like microorganism that exists all around us - in soil, on plants and even in the air. It has existed for so long, it is referred to as 'the oldest plant cultivated by man.' The main purpose of yeast is to serve as a catalyst in the process of fermentation, which is essential in the making of bread.

What is the purpose?

The purpose of any leavening agent is to produce the CO2 gas that makes bread rise. Yeast is no different. Yeast does this by feeding on the sugars in flour, and producing a waste product carbon dioxide in the process. With no place to go but up, this gas slowly fills the bred with tiny air pockets that gives the bread its fluffiness. A very similar process happens as bread rises. Once the bread has baked, this is what gives the bread its airy texture.

Answer 2

Yeast is actually a living microorganism, a fungus, that converts fermentable sugars in the bread dough into (among other things) carbon dioxide. The CO2 "inflates" the dough; the yeast makes countless tiny bubbles of the gas. This is the mechanism behind the dough rising.

Answer 3

The purpose of any leavening agent is to produce the CO2 gas that makes bread rise. Yeast is no different. Yeast does this by feeding on the sugars in flour, and producing a waste product carbon dioxide in the process. With no place to go but up, this gas slowly fills the bred with tiny air pockets that gives the bread its fluffiness. A very similar process happens as bread rises. Once the bread has baked, this is what gives the bread its airy texture.

Answer 4

Yeast reacts with sugar in the recipe to produce carbon dioxide gas (the stuff that puts the fizz in pop !) this makes tiny bubbles in the dough mixture - causing it to increase in size (like blowing up millions of tiny balloons) and so it makes the dough rise.

Answer 5

Uncooked bread contains sugar and yeast. Yeast is an organism which eats the sugar and farts carbon dioxide. The carbon dioxide gas makes bubbles in the dough. The bubbles do not break and the bread is expanded or rises because it is full of bubbles.

Answer 6

The yeast is a living organism and therefor needs to eat when the yeast eats it makes a byproduct called carbon dioxide (CO2) it is this gas that makes the bread rise.

Answer 7

yeast is a fungus, it feeds on the metabolize sugar It then produces ethanol and carbon dioxide (co2) which makes the bread expand and rise because of the gases within.

Answer 8

CO2 produced by aerobic respiration make bread rise.