Evolution of craft beer aroma over time as influenced by hopping technique (dip vs. dry hopping)

The increasing popularity of India Pale Ale or IPA (heavily hopped beers) highlighted the necessity for a better understanding of the chemistry behind the unique aroma of these beers. The hoppy aroma of these beers comes from the complex composition of the essential oil provided by hops, and from the chemical changes that can occur to its components during fermentation. The final aroma of the beer is the result of countless interactions between the different volatile chemical class (i.e., terpenes; esters; higher alcohols and aldehydes) and their evolution during the beer shelf-life. The objective of this study is to evaluate how a yeast strain with high β-glucosidic activity and a new hopping technique work together to influence the aromatic profile of beer. In this paper, we compared the traditional dry hopping technique (DRY beers) with the more recent dip hopping technique (DIP beers). Both beers were monitored over a three-month storage period using sensory analysis and gas chromatography. The analytical data showed varying developments in aroma between the two beers over the period, consequently influencing their chemical composition.