Thiol Research Partnership with Oregon State University

Much of the thiol research available is based in wine or selective media, typically not in beer. In an effort to bridge this gap and advance thiol research in brewing, Lallemand Brewing has partnered with Oregon State University to conduct studies that examine practical solutions brewers can use to influence thiol expression. This on-going study is broken into different parts, with part one focusing on temperature and nitrogen influences on thiol levels and expression.

Temperature and Thiols

The first part of this study was to determine the effect temperature has on thiol release in general. Overall, it was observed that free thiols increase with an increase in fermentation temperature.

Upon closer inspection, LalBrew Diamond™ was shown to exhibit 2-3 times more free 3SH (grapefruit, citrus), making this strain a surprisingly high thiol producer. ¹  

Free Amino Nitrogen (FAN)

Nitrogen concentrations in wort have often been thought of as a lever in thiol production; where lower nitrogen levels were hypothesized to correlate to higher thiol levels. This study found that lower FAN (free amino nitrogen) levels did correlate with an increase in free thiols; however, the subsequent sensory panel did not observe this correlation, thus confirming that nothing is ever straightforward in hop biochemistry and beer sensory.  

It is worth noting that a decrease in wort FAN also influences fermentation performance, resulting in:  

The sensory panel results of this study were mixed. In high temperature environment, sensory panellists observed more fruity or tropical aromas, but these aromas were yeast dependent. Notably, LalBrew Diamond™, scored low on sensory even though ranking fairly high in 3SH and 4SMP.²

In the nitrogen study, though the analytical data suggested a high amount of thiols in a low FAN environment, the sensory panel observed a less fruity or tropical aroma in a low FAN beer.²

These mix results suggest that thiols only paint one part of the overall tropic/fruit sensory in beer. Brewers should consider all sensory compounds (thiols, terpenes, esters, lactones, etc..) as participating in a beer’s overall aromatic intensity.

 References for Recent R&D

¹ Samia, Ronald, Oregon State University, Fermentation temperature impacts polyfunctional thiol biotransformation and release in beer, EBC 2024 Presentation

² Samia, Ronald, Oregon State University, Wort Nitrogen Levels Impact Polyfunctional Thiol Biotransformation in Beer, World Brewing Congress, 2024.