Transfer of flonicamid and its metabolites (TFNA, TFNG and TFNA-AM) from hops into beer during wort boiling and during dry hopping

Abstract

Flonicamid is a systemic aphicide that is selectively effective against aphids. In this study the substance transfer of flonicamid and its metabolites was investigated during hop addition at the beginning of boiling and during dry-hopping with a real flonicamid treated hop sample. For the transfer from hops into wort, wort-hopped beer, and dry-hopped beer, transfer rates of 96 %, 103 %, and 88 % were evaluated respectively. From these results, the processing factors for flonicamid and its metabolites TFNA and TFNG (calculated as flonicamid) were defined as 0.001. These results showed that flonicamid, TFNA, and TFNG are fully soluble in wort and are stable during wort boiling and fermentation. In a second investigation, we analyzed 16 commercial Pilsner type beer samples of different brands in a market survey. As a result, flonicamid could not be detected in any of the samples, whereas the degradation products TFNA and TFNG were detected.