Second life of hops: Analysis of beer hopped with hop pellets previously used to dry-hop a beer

Dry-hopping process is the cold extraction of substances found in hops into beer. This method has gained popularity among beer brewers in recent years because it aids in the introduction of intense flavour and aroma into fermented beverages. However, using a large amount of hop material may result in significant losses of spent hops and beer. In this study, test batches of beer hopped with recycled hops were made with varying dosages of recycled material. Beers brewed with recycled hops had lower IBU (international bittering units) and lower concentrations of hop-derived volatiles (such as aromadendrene, α-terpineol, methyl geranate and α-caryophyllene), but they retained the same level of antioxidant activities (assessed by ABTS∙+, DPPH∙ and FRAP assays), concentration of phenolic compounds and many yeast-derived volatile metabolites as the model beer (hopped with new hops) and acquired higher notes for taste parameter in the sensory analysis.