Hops, the seed cone of the <i>Humulus lupulus</i> plant, contain α-acids which are a major flavoring ingredient in beer. The quantity of α-acids varies with the type of hops, method of processing, storage conditions, and length of storage.  To the brewer, the amount of α-acids contained in the hops is an essential quality control factor. This is due to the isomerization of α-acids into iso-α-acids during the brewing process, which adds bitterness to the flavor of the beer.  Small batch craft brewing is one of the fastest growing industries today, experiencing a six-fold increase in the number of breweries and more than doubling its workforce in less than a decade. Craft brewers are more susceptible to variations due to their smaller batch sizes which requires more frequent brewing thus leading to consistency and quality problems. We hypothesized that variations in raw hops flavonoids and α-acids will lead to quality and consistency problems associated with these variations. The dissimilarities were determined by comparing raw hops content for flavonoids prior to their addition in the brewing process, to their subsequent content in the finished product. We assayed this variability utilizing both HPLC and UV-Vis spectrophotometric methods. We then formulated a before and after comparison, and determined its effect on the flavor of the beer.

Batch to batch variation of flavonoids and alpha-acids in craft beers

2019 Spring National Meeting

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