How does the presence of brewers yeast in beer contribute to the fermentation process and overall flavor profile of the final product?

Brewers yeast plays a crucial role in the fermentation process of beer by converting sugars into alcohol and carbon dioxide. This process creates the desired alcohol content and carbonation in the final product. Additionally, brewers yeast produces various compounds during fermentation that contribute to the flavor profile of the beer, such as fruity esters and spicy phenols. Overall, the presence of brewers yeast is essential for both the fermentation process and the development of the unique flavors in beer.