Headspace‐solid phase microextraction and GC‐MS followed by multivariate data analysis to study the effect of hop processing type and dry hopping time on the aromatic profile of top‐fermented beers

Abstract

AbstractThis study analyzes the impact of the pelletizing process and the contact time of hops with beer samples on the aroma of beers produced with a dry hopping technique. Eight different hopped beer samples were produced, varying in terms of hop variety (Cascade or Columbus), two different commercial forms of hops (pellets or whole flowers) and two dry hopping times (4 or 7 days). A non‐hopped beer was also produced to help understanding which compounds emerge from the dry‐hopping technique alone. The volatile fraction of the beers was studied by headspace‐solid phase microextraction and gas chromatography‐mass spectrometry. More than 90 compounds were identified with the help of Kòvats retention index, injection of standards, and comparison with mass spectra of the NIST library. To assist in the interpretation of the large data volume, principal component analysis was used. The findings confirm that the pelletizing process and the dry hopping time influence to different extents the aromatic profile of the beers produced, and the compounds responsible for these changes were identified.