Brewer’s yeast is a by-product of the brewing industry. After 5-10 succeeding beer fermentations, the yeast, due to increasing contamination, loses its viability and activity and is no longer acceptable for making beer. The yeast then becomes surplus and can be used for the production of food flavors, feed formulations or as nutritional yeast food.


Over the years, the term "brewer’s yeast" has become generic. Primary grown baker’s yeast (not a by-product of the same strain of yeast used by bakers to make bread) is often sold as brewer’s yeast because the term is familiar to the consumer. The processing and drying of this yeast is carefully controlled so it remains inactive, making it easily digestible and yielding valuable amounts of B-complex vitamins and protein for assimilation.

Another form of brewer’s yeast is labeled as "DEBITTERED Brewer’s Yeast", due to neutralization of the bitter flavor of hops. This form of yeast is almost always certain to be brewer’s yeast. However, due to a lack of standards governing this particular label, product packaging may claim to contain "brewer’s yeast" and actually contain inactive baker’s yeast.