Since 1947 Premium - Natural - Unflavored Unsweetened - Unfortified Nothing Added Naturally Delicious Suitable for Vegetarians Dietary Supplement A natural primary Brewer's Yeast (Saccharomyces cerevisiae) that provides a source of amino acids, B-complex vitamins and more. Source: Most Brewer's Yeast are derived from the fermentation of beer: Such fermentation involves using grains (such as rice or wheat), malt, active yeast and the dried flowers of hops. Although efforts are made to debitter the yeast prior to final drying operations, most Brewer's Yeasts are, nevertheless, left with a bitter odor. After fermentation, the yeast is collected and dried using special techniques to preserve its protein, vitamin and mineral content.