Yeast Powder

 the strains of yeast commonly used in baking bread and bakery products, serving as a leavening agent which causes the bread to rise (expand and become lighter and softer) by converting the fermentable sugars present in the dough into carbon dioxide and ethanol. Baker's yeast is of the species Saccharomyces cerevisiae,[1] and is the same species (but a different strain) as the kind commonly used in alcoholic fermentation, which is called brewer's yeast.[2] Baker's yeast is also a single-cell microorganism found on and around the human body.
The use of steamed or boiled potatoes,[3] water from potato boiling,[4] or sugar in a bread dough provides food for the growth of yeasts; however, too much sugar will dehydrate them.[5] Yeast growth is inhibited by both salt and sugar, but more so by salt than sugar.[6] Some sources say fats, such as butter and eggs, slow down yeast growth;[7] others say the effect of fat on dough remains unclear, presenting evidence that small amounts of fat are beneficial for baked bread volume.[8]