What forms carbon dioxide co2 during fermentation and is used to help bread rise?

The form of carbon dioxide (CO2) produced during fermentation that helps bread rise is dissolved CO2.

Here's how it works:

1. Yeast consumes sugar: Yeast, a single-celled fungus, consumes sugars in the dough.

2. Fermentation: As a byproduct of this process, yeast produces CO2 and alcohol.

3. CO2 bubbles form: The CO2 produced dissolves in the dough's water, forming tiny bubbles.

4. Gluten traps the bubbles: The gluten in the dough acts like a net, trapping these bubbles and expanding as they grow.

5. Rising bread: As the CO2 bubbles expand, they push the dough outwards, causing the bread to rise.

So, while CO2 is produced in gaseous form during fermentation, it's the dissolved CO2 that plays the crucial role in making bread rise.