Why does yeast make bread rise?
If you’ve ever taken a bite of bread you’ve made, you may wonder how simple ingredients like flour, salt and yeast can produce raised, sometimes wonderfully bubbly bread. It makes people a little squeamish to know it that yeast makes bread dough rise because it is a live single-celled organism. Specifically it is a variety of fungi called Saccharomyces cerivisiae, which is harnessed to eat, drink and be merry, before dying a quick death when exposed to oven heat. You can buy several different types of yeasts on the market. The first of these is called live or fresh yeast. This is relatively unstable, requiring refrigeration, and it has a very short shelf life. Dried versions, sold in packages or cubes is essentially cells of Saccharomyces cerivisiae, which are waiting to be activated. Like many fungi types, yeasts for bread dough responds to warm water, which begins to bring the little cells to life. Then when exposed to sugars in bread and in flour, it begins to eat, digesting portion
Yeast (fungus) makes bread rise when it responds to warm water and exposure to the sugars in the bread/flour. The yeast starts to eat, actually digesting some of the sugar! The process is short and the yeast dies in a few hours time. Next time you eat a slice of bread bow your head in silence for moment and give thanks to the yeast that sacrificed their lives!
