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, alpha-terpineol, methyl geranate and alpha-car-yophyllene), but they retained the same level of antioxidant activities (assessed by ABTS center dot +, DPPH center dot 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.

Automated summary

The study found that beers brewed with recycled hops had lower bitterness and hop aroma concentrations, but had similar antioxidant activities, phenolic compound concentrations, and yeast-derived volatile metabolites as beers brewed with new hops. The sensory analysis also showed that the beers brewed with recycled hops had higher taste ratings.