A comprehensive revaluation of small-scale congress mash protocol parameters for determining extract and fermentability

The objective of this study was to comprehensively and methodically evaluate the small-scale mash parameters of the standard Congress (EBC and ASBC) mash protocol in order to modernize this protocol so it better emulates modern commercial brewing practices. For the recommended final 65°C mash protocol, the key parameters were grist milling at 0.7 mm by disc mill, an initial grist/water ratio of 1:3, an initial mash temperature of 65°C, and an initial mashing phase of 65°C for 60 min. Of lesser importance, but still adopted due to widespread use in commercial brewing, was the addition of CaSO_{4 (0.3 mM) and completion of mashing at 74°C, after which the grist/water ratio was decreased to 1:6 before cooling and lautering. The “final 65°C” mash protocol was compared with the Congress mash protocol and a simple 65°C variant (“old 65°C”) mash protocol to determine the influence of mash protocol on extract and fermentability using a selection of 29 commercial malts. It was demonstrated that the choice of mash protocol applied had subtle, but important, impacts on the determination of extract and prediction of fermentability. Through a relatively simple modification of the small-scale wort production protocol, measurement of malt lautering performance, based on the volume of wort lautered at 25 min, was also proposed. The investigation showed that the mash protocol used could interact with subtle differences in malt characteristics, which could alter the relative importance of the predictive parameters of important malt quality characteristics such as extract, fermentability, and lautering. Researchers and malt quality technicians should be aware that these subtle influences could potentially result in unexpected biases in routine malt analyses and research investigations of components that influence malting and brewing parameters.}