In this work we investigated the influence of magnesium ions present in the technological water (in the range of 0-150 ppm) on the content of magnesium and zinc ions in the wort. We tried to verify if there is inhibition of release of the ions from the malt by an increased content in water. It was revealed that the content of magnesium higher than 50 ppm, results in a lower rate of magnesium ions release from the wort. It also turned out that magnesium present in water even at low concentrations (starting from 15 ppm) decreases the concentration of zinc ions. When the water contained 150 ppm Mg1 *, zinc content in the resulting wort was 50% of the original amount (when deionized water was used).