What is the role of yeast in beer production?

The role of yeast in beer production is fundamental, as it is responsible for fermenting the sugars present in the malt. During fermentation, yeast consumes these sugars and through metabolic processes converts them into alcohol and carbon dioxide (CO2). This not only results in the alcoholic content of the beer but also contributes to the effervescence or carbonation, making the beverage enjoyable.

Other options do not accurately describe the primary function of yeast. While sweetness is provided by the malt, yeast ferments these sugars rather than adding sweetness itself. Color in beer primarily comes from the type of malt used and the brewing process, not from yeast. Bitterness in beer is typically derived from hops rather than yeast, which has a different role in the brewing process. Thus, yeast's primary function is to react with the malt, leading to the creation of alcohol and CO2, solidifying its essential role in brewing.