On the Transfer Rate of Geraniol with Dry Hopping

When calculating the transfer rate of geraniol in dry hopped beers based solely on the initial value in hops, there are tremendous fluctuations of between about 40% and over 200%. Some varieties, including Cascade, Hallertau Blanc and Polaris, contain considerable amounts of geranyl acetate in addition to geraniol. However, since no trace of geranyl acetate can be found in the beer, even at high dosages, it can be concluded that at least under these conditions (dry hopping before maturation and storage) geranyl acetate is hydrolyzed and geraniol is released. Including the dosage of geranyl acetate into the calculation of the transfer rates, this yields values of 36 % to 62%, a variation clearly within the limits of error analysis.

BrewingScience - Monatsschrift für Brauwissenschaft, 67 (March/April 2014), pp. 60-62