Fate of triazole fungicide residues during malting, mashing and boiling stages of beermaking

The fate and behaviour of five sterol biosynthesis-inhibiting (SBI) fungicides (cyproconazole, diniconazole, epoxiconazole, flutriafol, and tebuconazole) during different stages of beermaking (malting, mashing and boiling) on laboratory scale was assessed. A significant correlation (r > 0.93, P < 0.05) was observed between amounts removed after steeping and the octanol/water partition coefficient (as log KOW) of the fungicides. Although in smaller proportion than steeping, germination and kilning were significant stages on the fungicide dissipation. The carryover after malting ranged from 30% to 40% of the initial residues on barley. After mashing, a substantial fraction was removed with the spent grains in all cases (36–49%) whereas a weak fall after boiling was observed for the fungicide residues (⩽2.5%). The calculated transfer factors (TFs) do not indicate a concentration effect after processing in any case (TFs < 1). Finally, after the storage of malt and spent grains (3 months) a slow fall in the residual content was observed.