YEAST: A small and helpful friend

One of the most important fermentation reactions is alcoholic fermentation, and the responsible of this is our little friend Yeast.
Yeast (Sacharomyces cerevisae) is an organism that transforms simple sugar such as sucrose into ethanol and carbon dioxide.
At first wild yeast (natural yeast present in the environment) was used, even in ancient Egypt for bread and beer making, but then with the discovery of microscopes an microbiology specific types of yeast has been adapted to a variety of processes.
Therefore yeast is the base of a lot of different everyday processes even if we don't know about it.