There are many chemical changes that take place during wort boiling, to include the oxidation of polyphenols, production of melanoidins via Maillard reactions, protein precipitation, enzyme inactivation, and isomerization of hop acids. Hops are one of the most important raw materials used in the production of beer as it is responsible for the bitter flavor and aroma of beer. The metabolites in hops also provide beer with other qualities like flavor stability, foam stability, microbial stability, color, and mouthfeel. During the wort boiling, the α-acids are isomerized to iso-α-acids. These products can lead to various ratios of the cis/trans-iso-α-acids, which can affect the kinetics of oxidative degradation as well as the bitter taste development in the final product. Environmental changes to the terroir can lead to alterations in the acid profiles of individual hop cultivars. Therefore an accurate assessment of initial α-acid components is clearly important for brewers in determining a consistent product. Additionally, determination of the fate of these compounds throughout the brewing process is of interest for studies focused on the stability and shelf life of the product. Here we present our initial findings of acid profiles from hop pellets and the corresponding isomerization and degradation products as a function of wort boiling at a local craft brewery.

Lifetime and fate of hop (Humulus lupulus) acids in craft brewing cultivars by HPLC analysis

ACS Spring Meeting 2021

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