Why is it impossible for you to make homemade root beer using a sugar substitute?

Homemade root beer relies on fermentation, which requires sugar as food for yeast to produce carbon dioxide and alcohol. Most sugar substitutes, like Aspartame or stevia, do not ferment in the same way, meaning they won't provide the necessary energy for yeast fermentation. Additionally, sugar substitutes can alter the flavor and texture of the final product, making it difficult to achieve the traditional taste of root beer. Thus, using a sugar substitute hinders the brewing process and affects the overall outcome.