Is not a form of baker's yeast?

Baker's yeast primarily refers to strains of Saccharomyces cerevisiae, which are used in baking due to their ability to ferment sugars and produce carbon dioxide, helping dough to rise. Other forms of yeast, such as brewer's yeast (also Saccharomyces cerevisiae but prepared differently) or wild yeasts used in sourdough, are not considered baker's yeast in the traditional sense. Additionally, non-yeast leavening agents like baking powder or baking soda are also not forms of baker's yeast.