Uptake and Release of Ca, Cu, Fe, Mg, and Zn During Beer Production

摘要

Metal ions play a crucial role in the brewing process and in the finished beer. In this study, the uptake of Ca, Cu, Fe, Mg, and Zn ions from raw materials and release in by-products and carryover to the finished beer was assessed in lab-scale brewing trials using microwave-digestion inductively coupled plasma optical emission spectroscopy. From all raw materials (brewing water, Pilsner malt, hops, and yeast) tested, hops appeared to possess the highest metal ion concentration, with the exception of Zn, where yeast was highest. Malt was still found to be the biggest source of metal ion uptake (approximately 96%), considering the amount used for brewing. In the by-products, metal ions were highest in hot break, with the exception of Zn; however, considering the masses, 88.2% of the metal ions measured remained in the spent grains, 4.8% were found in the hot break, and 3.4% were released in the fermentation sediments. Ultimately, 0.1% Fe, 0.4% Zn, 3.1% Cu, 6.3% Ca, and 15.1% Mg were detected in the finished beer. The data were compared with an industrial-scale brewing trial and could be confirmed with minor deviations.