Effect of wheat malt on the concentration of metal ions in wort and brewhouse by-products

Abstract

The ionic composition of brewer's wort depends on the raw materials and processing employed. The macroelement content is usually sufficient for yeast, but some of the microelements (mainly zinc) often need to be supplemented to the wort. Wheat malt is used as an adjunct in the production of beer, replacing up to 60% of barley malt. In this study, the effect of replacing barley malt with wheat malt on the concentration of magnesium, manganese, iron and zinc ions in brewer's wort was investigated. The ionic content of both the raw materials and by-products were analysed. Similar amounts of magnesium ions were found in wheat malt and barley malt, whereas, manganese, zinc and iron were more abundant in the wheat malt. Nevertheless, wheat malt did not cause a significant change in ion concentration in the first wort (except for magnesium; its content decreased). The ionic content in the spent grains increased owing to wheat malt addition; the concentration of ions in the wort decreased after wort boiling (Mn2+ and Fe) or remained unaffected (Mg2+ and Zn2+). It was concluded that the ionic composition of the wort depends mainly on the removal rate of ions from the wort during mash filtration and hot trub separation, rather than on the actual amount of ions in the raw materials.