Glossolalia
Well-Known Member
I'm a big fan of beer styles with strong perceptible ester products. I was Googling sources of Japanese hops, and I accidentally ran across this dissertation from a graduate student at Kyoto University and Asahi Breweries. The crux of his project was that he was trying to identify the chemical sources of certain particular aroma characteristics of different hop varieties. Anyhow, in chapter 5, to test some of the compounds he finds in previous studies, he purposely ages the hops (at 40 C for 30 d) and compares them to controls stored at 4 C (presumably he assumed that the compounds would have disappeared upon degradation of the hops).
He finds that for late addition hopping, aged hops, while exhibiting decreased alpha-acid concentrations (expected), actually exhibited increased non-isohumulone bittering compounds, leading to greater IBU contribution to the wort. More interestingly, for me at least, is aging resulted in sensory evaluation of the particular hop going from resinous/floral/green to citrus/muscat-like/grape. He hypothesizes that this is because of the esterfication of alpha-acid degradation products.
I know aged hops are often used in lambic production, but those are several years old, contribute few IBUS, and often are described as "cheese-y." Has anyone here purposely aged their hops similar to what is described in the dissertation here? If so, did you get similar results to those reported in the dissertation?
He finds that for late addition hopping, aged hops, while exhibiting decreased alpha-acid concentrations (expected), actually exhibited increased non-isohumulone bittering compounds, leading to greater IBU contribution to the wort. More interestingly, for me at least, is aging resulted in sensory evaluation of the particular hop going from resinous/floral/green to citrus/muscat-like/grape. He hypothesizes that this is because of the esterfication of alpha-acid degradation products.
I know aged hops are often used in lambic production, but those are several years old, contribute few IBUS, and often are described as "cheese-y." Has anyone here purposely aged their hops similar to what is described in the dissertation here? If so, did you get similar results to those reported in the dissertation?
