Brewing Fundamentals, Part 2; Fundamentals of yeast nutrition

Brewer’s wort is a complex medium produced from a cereal extractand fermented by yeast to produce beer. Brewer’s yeast, usually eitherSaccharomyces cerevisiae or S. pastorianus, requires carbohydrates,sources of nitrogen, oxygen, ions, and vitamins to enable this transformationto occur. A well-aerated (oxygenated) all-malt wort shouldprovide sufficiently for all these needs, allowing for some yeast growthand ultimately for fermentation with the production of ethanol, carbondioxide, and metabolic by-products that contribute the desired flavorcharacteristics to the final beer. A deficiency in of any of these nutritionalresources will have an impact on brewery efficiency, often associatedwith a “stuck” or “hung” fermentation. This review aims toprovide brewers, and students of brewing, with an overview of theroles that these wort nutrients play in fermentation.