Dean G. Hauser, Karli Rose Van Simaeys, Scott Lafontaine, and T.H. Shellhammer

Journal of the American Society of Brewing Chemists: October 2019. pages 1943-7854 (Online). DOI: 10.1080/03610470.2019.1668230

In this study, reseachers from Departments of Food Science and Technology of Oregon State University (Corvallis) show that the use of hops by dry-hopping may be more efficiently by multi-dose additioins. Authors present evidence supporting the hypothesis that lower and multiple dose dry-hop additions may offer greater hop aroma potential in beer than single additions at higher rates.

ABSTRACT. Multi-stage dry-hopping is a technique that is widely used by brewers to achieve intense hop aroma in beer. However, a thorough analysis of its efficacy does not exist in the published literature. The goal of this study was to compare the properties of beers produced by single or two-stage dry-hopping at the same cumulative rate. On the pilot scale (80–100 L), an un-hopped base beer was subjected alternately to single- or two-stage dry-hop additions at 386, 772, and 1544 g/hL using Centennial hops. Separately commercial beers (∼350 hL batch size) were dry-hopped at 733 g/hL in single or two-stage additions using a combination of Amarillo, Simcoe, Cascade, Citra, and CTZ pellets. Pilot scale dry-hopped beers showed increases in residual extract, pH, bitterness units, humulinones, and total polyphenols, accompanied by a decrease in iso-α-acids with increasing hop dose. Changes in bitterness units, humulinones, and iso-α-acids all appeared to be more pronounced in the two-stage dry-hopped beers. In contrast, commercial beers were nearly identical in terms of chemical composition. Significant increases in six aroma attributes scaled by a trained panel were observed as a result of two-stage dry-hopping in the pilot scale treatments. Slight increases in aroma potential were observed for the commercial beer made with two-stage additions, although these differences were not statistically significant. These results illustrate the impact multi-stage dry-hop additions have on beer aroma, and provide direction to brewers to consider whether multi-stage dry-hopping may yield desirable results while potentially using less hop material.