The hops used as a raw material for beer contain α-acids (humulones) and β-acids
(lupulones). The α-acids are converted to iso-α-acids (isohumulones), which are bitterness
components of beer, by isomerization in the brewing process. The β-acids are not strongly
related to the strength of beer bitterness but are thought to influence the balance of bitterness.
International Bitterness Units (IBU) are generally used in measurements of the bitterness
value. The IBU value is calculated based on the results of solvent extraction of the bittering
components in beer and spectrophotometric measurement. Although this is a simple method,
overestimation is possible if the sample includes substances.
High performance liquid chromatography (HPLC) is generally used in analyses of these
compounds. This article describes examples of a high speed analysis of the α-acids and β-
acids in hops with a Shimadzu Nexera XR HPLC, referring to EBC (European Brewery
Convention) and ASBC (American Society of Brewing Chemists) and IBU was also measured
with a UV-1900i UV-Vis spectrophotometer and compared with the results of the HPLC.