Master Brewers Association of the AmericasEducationWebinars on TapThe IBU and Perceived Bitterness

​The IBU and Perceived Bitterness: How half a century ofevolution in the brewing industry has affected the relevance of the IBU​​

Broadcast Date: Wednesday, February 22, 2017 | 11:00 a.m. - 12:00 p.m. Central

View the​ Web​inar

Webinar Summary

The protocol for the IBU was agreed to in 1967. In that era, almost all beers were lager- or pilsner-style, pellets and extracts were rarely used and the baled hops used were stored with little temperature control for 6-18 months before use and were excessively oxidized by today’s standards. The IBU also assumes the pH of beer is close to 4.3 and that it was not dry-hopped. Beers of the day also seldom exceeded 6.0% ABV or 50 IBUs.

The world of brewing has changed drastically in the last half-century, with beers pushing close to the solubility limit for hop resins, dry-hopping that not only adds high amounts of hop compounds normally not found in beer, but increases the pH, which is known to increase perceived bitterness in beer. Un-isomerized alpha-acids and hop polyphenols solubilized in dry-hopped beers also likely alter perceived bitterness. Sour beers may have a pH as low as 3.5. This was unheard of 50 years ago and influences perceived bitterness.

These factors are explored by a trained taste panel and their influence on perceived bitterness are modeled to help brewers better understand the IBU and its relevance to their products.

Anyone interested in QA/QC testing, brewing, and/or sensory would benefit from this webinar!


Webinar Agenda:

  • Introduction and History of the IBU
  • Calibration of the Taste Panel
  • Data and Results
  • Conclusions and Future Work
  • Q&A Session

What Attendees Will Take Away:

  • The need for more reliable, empirical data on perceived bitterness (and dry-hopping
  • The need for additional tools and tests for brewers to make use of that data. We can get there through collaboration

About the Presenter​

Kurt Driesner

Kurt Driesner
Urban Chestnut Brewing Company

Kurt Driesner's master’s work was in environmental toxicology at Southern Illinois University in Edwardsville, IL. His previous education and experience focused on neuroscience, pharmacology, psychopharmacology, and psychology at the University of Illinois at Urbana-Champaign. He has been working at Urban Chestnut Brewing Company since 2012, where he functions as the quality assurance manager.