Jeffrey Cohen (1); (1) Stone Brewing, Escondido, CA, U.S.A.


Free Amino nitrogen (FAN) has been studied in beer for over 40 years as it is an essential nutrient for yeast during fermentations; however, the majority of the available reference material is based on lagers and other traditional beer styles. Innovation from the craft brewing industry creates an opportunity to expand this testing to encompass other styles that are now widely present in the domestic beer market. Using the internationally recognized ninhydrin method (ASBC Wort-12A), seven craft beer styles, including two IPAs, two double IPAs, a session IPA, a hoppy pale ale and an American strong ale, were tested. During this ongoing study, wort and corresponding chilled pre-filtered beer samples are collected during the fermentation processes; their respective FAN levels are trended and have been used to help establish baseline averages for each respective brand. On average, the IPA samples tested to date have FAN levels of approximately 250 mg/L in the wort and 133 mg/L in the pre-filtered samples. In contrast, the higher gravity double IPAs have higher wort and pre-filtered FAN levels, 316 mg/L and 175 mg/L, respectively, which is expected due to the additional malt used. It is known that FAN is a viable tool to monitor fermentations and evaluate yeast health, so the purpose of this experiment is to leverage it as a primary metric to track significant process changes made between batches. Test data collected while tracking a significant double IPA process change correlates with much more efficient fermentations, which further demonstrates that monitoring FAN levels in American craft ales, can be considered a critical control point for supporting business decisions.

Jeffrey Cohen attended the University of California, Davis, from September 2010 until June 2014, when he graduated with honors, receiving a B.S. degree in food science and technology, with an emphasis on brewing science. He began working at Stone Brewing. in July 2014 as a quality assurance assistant in the analytical, microbiological and sensory labs. Jeffrey is currently working as a quality assurance technician, with a primary focus on the analytical chemistry of beer and the brewing process. Jeffrey has recently been focusing on free amino nitrogen testing, gluten analysis and packaged beer quality at Stone. He plans on furthering his research on FAN and hopes to expand his research to other aspects of brewing quality.