What gas does yeast give off?

Yeast is a type of fungus that converts sugars into alcohol and carbon dioxide through a process called fermentation. During fermentation, yeast breaks down the sugar molecules into smaller molecules, producing alcohol and carbon dioxide gas as byproducts. The specific type of gas produced by yeast depends on the fermentation conditions and the strain of yeast used. In most cases, yeast produces carbon dioxide gas (CO2), which is commonly known as "yeast gas."

Carbon dioxide gas is colorless, odorless, and heavier than air. It is released as tiny bubbles during the fermentation process, causing dough to rise and making beer and wine fizzy. The rising of dough is due to the carbon dioxide gas becoming trapped in the dough, forming small pockets that expand as the gas expands. This process gives baked goods their characteristic light and fluffy texture. In beverages like beer and wine, the carbon dioxide gas contributes to the effervescent and bubbly nature of these drinks.

Carbon dioxide is also a natural byproduct of cellular respiration in yeast cells. During cellular respiration, yeast converts sugars into energy, producing carbon dioxide as a waste product. This process occurs even in the absence of fermentation.

Overall, the main gas produced by yeast during fermentation is carbon dioxide gas (CO2), which is responsible for the rising of dough and the fizziness in fermented beverages.