Using grain and water, the brewer creates a sugary liquid called wort and then adds yeast to it. That yeast then eats up the sugar and creates alcohol, carbonation, and other compounds (esters, phenols, etc.) that give beer its particular flavor. The majority of beers use a yeast strain called Saccharomyces.
Alcoholic fermentation is a biotechnological process accomplished by yeast, some kinds of bacteria, or a few other microorganisms to convert sugars into ethyl alcohol and carbon dioxide. Alcoholic fermentation begins with the breakdown of sugars by yeasts to form pyruvate molecules, which is also known as glycolysis.