Table of Contents
Nitrogen fertility practices in the field influence the accumulation of nitrate during the production of hop-forward beer
T. H. Shellhammer, S. R. Lafontaine, A. E. Iskra, J. Clawson, K. M. Trippe, C. L. Phillips and D. H. Gent
Hops and malt are the two main sources of nitrate in beer, with hops being the primary source in beers that are late-hopped or dry-hopped. A proof-of-concept study was performed to characterize how nitrogen fertilizer dose applied in the field during hop production influences nitrate accumulation in hop-forward beers. To quantify the dose-response relationship two contrasting nitrogen fertilizer rates, 90 and 269 kg/ha, were used to produce hops that differed in their nitrate concentrations (852 and 2651 mg/kg of nitrate, respectively). These rates were selected to represent extremely low and extremely high nitrogen fertilizer commercial rates, respectively. Hop-forward beers (kettle hopped at 0.52 g/L, whirlpool hopped at 2 g/L, and dry-hopped at 4 g/L) were produced with these hops and nitrate accumulation was quantified after each hop technique to determine the overall contribution of each hopping technique on the nitrate concentration in beer, as well as if the different hop treatments yielded beers with different nitrate levels. Nitrate accumulation following each hop technique was associated with nitrate concentration of the hops and, ultimately, the rate of nitrogen fertilizer applied in the field. As supported by previous studies, nitrate accumulated quantitatively with respect to the different hop techniques, with dry-hopping resulting in the largest increase in nitrate, followed by whirlpool additions, and then kettle hop additions. Although beer is a minor dietary source of nitrate, our results indicate that reducing nitrogen fertilization rates in the field can reduce nitrates in hop-forward beers.
Descriptors: brewing, dry-hopping, fertilizer, hop-forward beer, nitrate accumulation, nitrogen
BrewingScience, 74 (July/August 2021), pp. 88-91
