Transfer of Nitrate and various Pesticides into Beer during Dry Hopping

Abstract

We describe the transfer of nitrate and the pesticides azoxystrobin, dimethomorph, myclobutanil and quinoxyfen from contaminated hops to the beer during wort production and dry hopping. The experiments reported comprise of two experiment series conducted in a 20 hL pilot plant. First, the substance transfer was investigated by dry hopping different base beers with different amounts of various hop varieties and products. Secondly, a beer was brewed and dry hopped exclusively with a hop that had a high load of the four aforementioned pesticides. The results are presented in terms of concentrations and processing factors. In a market survey, we also analyzed 14 commercial beer samples of different brands and types as well as different hop samples in regard to their nitrate concentrations which were in the range of 3.0 to 86.5 mg/L.