The fermentation process is very complex and the correct levels of Free Amino Nitrogen (FAN) and Yeast Assimilable Nitrogen (YAN), individual amino acids, and co-factors such as zinc are not always tracked to forecast yeast performance and risks of off flavors. Yeast is expected to provide brewers with the ideal quality at the end of fermentation with no off flavors during or after fermentation. But all too often poor yeast performance or off flavors appear including many derived from amino acids. One of the major contributors to yeast performance and potential off flavors are the amino acids coming from the grain and hop ingredients. A deeper understanding of the complex metabolic processes of yeast and its needs such as zinc, and a capacity to track FAN and YAN pre, during, and post fermentation, gives brewers more confidence in final quality of their product and risks of package-developed off flavors.

Learning Objectives:

• Understand where FAN comes from (malt, hops, adjuncts), what brewers can expect in their wort based on their malt selection and brewing practices, and why zinc is limiting in wort
• Get to know yeast nutrition, including strain and category-specific differences
• Hear practical examples of how to adjust zinc dosage to match yeast pitch rate and achieve better fermentation consistency and yeast viability