DETERMINATION OF ZINC IN BEER AND BREWING MATERIALS

Abstract

After wet‐ashing with sulphuric and nitric acids and preliminary extraction with dithizone, zinc is separated and finally estimated colorimetrically as the red dithizone complex. The method has been shown to be both reliable and accurate, and it is capable of detecting 0·001 mg. of zinc Various types of beer have been examined and results indicate that the zinc content at racking rarely exceeds 0·1 p.p.m. but, in the case of trade samples, values up to 0·25 p.p.m. have been noted. Malt, hops and yeast have been found to contain appreciable amounts of zinc, but this element could not be detected in brewing sugars. The bulk of the zinc of the malt appears to be retained in the spent grains. 1952 The Institute of Brewing & Distilling