Hop analysis: International cooperation and new challenges by craft beer

Martin Biendl (1); (1) Hopsteiner HHV GmbH, Mainburg, Germany

EBC Symposium
Monday, August 15  •  8:15 – 9:30 a.m.
Plaza Buiding, Concourse Level, Governor's Square 14

For many years, analysis of the most important constituents of hops and hop products has been based on international methods recommended by ASBC, BCOJ, and EBC. The driving force behind such a harmonization is the worldwide hop trade, so that hop suppliers, breweries and brewing institutes can rely on globally accepted analytical procedures. In addition, consistent calibration standards are necessary to guarantee reliable and reproducible results. For that purpose, already in 1994, the Joint EBC/ASBC Hop Standard Subcommittee was founded, followed in 1998 by the International Subcommittee for Isomerized Hop Alpha-Acids with members from ASBC, BCOJ, IoB and EBC. Today both are combined in the International Hop Standards Committee (EBC/ASBC/BCOJ), which has the ongoing task to release suitable calibration standards for the various HPLC methods used to analyze bitter acids relevant for hop quality and beer taste. In the past, alpha-acids, beta-acids, iso-alpha-acids and all kinds of their hydrogenated derivatives (rho-, tetrahydro-, and hexahydro-iso-alpha-acids) needed to be covered. However, with the growing importance of dry-hopped beers, some additional hop bitter components like humulinones and hulupones have to be considered today. Preparation methods for according chemically stable calibration standards were already developed and published by individual committee members, so their release can be expected in due course. Another challenge now is to enlarge the scope of existing methods for beer analysis in order to include such co-bittering substances as well. As result of recent investigations, the method Analytica-EBC 9.47, currently only recommended for the determination of iso-alpha-acids and their reduced forms, can be applied to a broader range of bitter acids present in dry-hopped beers. Besides the different spectrum of bitter components, this type of beer is mainly characterized by a large diversity of hop-derived volatile substances, including aroma-active terpenes, terpene alcohols, esters or thiols. To analyze such a multiplicity of compounds only present in the ppt to ppb range, sophisticated methods based on gas chromatography in combination with mass spectroscopy detection are essential. Prior to the actual measurement, beer sample preparation can be automated using techniques like purge-and-trap, headspace-trap, solid-phase micro-extraction or stir-bar sorptive extraction. Such techniques still need validation in collaborative trials. As long as there is no harmonized method, only the addition of labeled derivatives of the target molecules can be recommended in order to achieve reliable results.

Martin Biendl received a Ph.D. degree in organic chemistry from Regensburg University in 1990. He is head of the R&D/Analytical Department at the German branch of the Hopsteiner Group, one of the largest international hop-growing, -trading and -processing firms. His research experience is in the field of hop-related needs for the brewing industry and beyond. He is the representative of the International Hop Industry Cooperation in the EBC Analysis Committee and, since 2001, chair of the Hops Subcommittee. As EBC representative he is also co-chair of the International Hop Standards Committee.