50. Analyzing hoppy beer flavor—The winding road of a research tool merging into brewery quality control

Nils Rettberg (1), Sarah Thoerner (1); (1) VLB Berlin, Berlin, Germany

Technical Session 14: Hops II
Tuesday, August 16  •  9:45–11:30 a.m.
Plaza Building, Concourse Level, Governor’s Square 14

In recent years, hop aroma has emerged as a key quality characteristic of popular beer styles. Distinct late and kettle hop flavor is a key attribute of pilsners, lagers, and non-alcoholic beers, whereas appreciable dry-hop aroma is present in most pale ales, India pale ales, and beer specialties. Driven by the growing craft beer scene, hoppy beers are more frequently brewed at a large scale. Thus, efficient raw material input, steady brewing technology with regard to flavor formation, as well as consistent product flavor are highly relevant. As a consequence, the instrumental analysis of hop-derived odorants in beer advanced as a must-have analysis technique. Today, it is not only used in a handful of upscale research projects, but frequently requested for quality control purposes within breweries. The requirement for suitable methods is, to name one specific example, reflected by ASBC Technical Committee efforts to introduce a standardized method for the analysis of certain hop aroma compounds in beer. The increasing interest in hop aroma analysis surely requires standard methods, but is this possible and accessible for a majority of brewers in the near future? Unlike many other well-established quality control tools, hop aroma analysis is rather complex. The unique flavor of hoppy beers cannot be measured by analysis of a few marker molecules, moreover it is the characterization of a heterogenic and complex mixture of multiple odorants. The first reports on the analysis of hop-derived volatiles from beer date back to the 1960s and 1970s (the introduction of gas chromatography + mass spectrometry (GC-MS)), the winding road of this research tool merging into quality control has surely not ended yet. Overlooking today’s analytical capabilities, there are multiple ways to extract, separate, detect, and quantify hop aroma compounds from beer. Evidently, all have certain advantages and drawbacks, steady improvement is visible. In the current study, several methods (GC, GC-MS, GC-MS/MS) for hop aroma analysis are applied, analytical data is compared and controversial data discussed. The methods range from simple to sophisticated, aiming to give a preferably comprehensive overview on the key factors in hop aroma analysis. In a nutshell, different analytical tools deliver quite different results, indicating that precise and simultaneous quantification of multiple analytes strongly depends on the combination of sample preparation and quantification procedure. The more complex or selective the sample preparation procedure, the higher the demands for appropriate reference standards, calibration, etc. Is hop aroma analysis ready for quality control? It depends!

Nils (born 1983) is a trained as brewer and maltster. He holds a diploma in biotechnology with focus on brewing science, as well as a Ph.D. degree from TU Berlin. Nils is deeply interested in beer analysis, preferring to track molecules that make beer taste either terribly good or horribly stale. Currently, Nils is in charge of the VLB Research Institute for Instrumental Beer and Beverage Analysis.