THE EFFECT OF WORT pH ON COPPER FINING PERFORMANCE

Abstract

Copper fining trials with ale and lager worts under conditions whereby the pH of wort was artificially manipulated prior to fining, demonstrated that the optimal copper fining rate decreased with increasing values of wort pH. Clarification of acidified worts (pH<4.5) was poor regardless of the rate of copper finings addition. These results suggest that the mechanism of fining action cannot be explained by a simple electrostatic model of interaction between positively charged groups present on wort poly‐peptides (lysine, arginine and histidine) and negatively charged sulphonyl groups of carrageenan. Manipulation of wort pH may be exploited to ensure batch consistency in fining performance without the requirement for variation in the rate of addition of copper finings. 1995 The Institute of Brewing & Distilling