One of the brewer’s many choices during the brewing process is the selection of a yeast strain. The mixture of hot water and malt sugars created in the brewing process, called wort, is hearty a meal for the tiny fungus called saccharomyces. The yeast converts this meal into two by-products essential for our enjoyment of beer; alcohol and carbon dioxide. Ale yeast, known as saccharomyces cervisiae, prefers a warmer fermentation temperature and works quickly; on the other hand, lager yeast, saccharomyces uvarum, works more slowly and at cooler temperatures. Ale fermentation can be completed in as little as a week, and can impart earthy, fruity aromas prized in many beer styles. Lager yeast metabolize sulfites during their longer, cooler fermentation process which tends to give a “rotten eggs” smell to the fermenting beer. The longer fermentation and lagering thereafter eliminate this odor and produce a brew with a clean, crisp flavor profile.