An investigation into the extent of variation in the temperature, pH, yeast cell concentration and chemical composition of the contents of different regions within an industrial brewery fermenter during fermentation is described. A 2000 hl cylindro conical tank was fitted with an array of sampling tubes inserted at different heights and extending varying distances towards the centreline of the vessel. Temperature measurements were taken at the apex of the cone and the top and bottom of the cylindrical part of the tank. Constituents determined in the fermenting wort/green beer include fermentable sugars, ethanol and higher alcohols, esters, amino acids and diacetyl. The results are presented in the form of graphs and tables. It was found that during primary fermentation, the homogeneity of the contents of the vessel was initially poor due to the absence of mixing, but as carbon dioxide production increased, agitation by the rising gas bubbles caused the tank contents to be thoroughly mixed; the consequent homogeneity prevailed until the yeast began to flocculate and settle out of suspension, which led to a decrease in the homogeneity of some constituents. The increased tank pressure required during maturation made it necessary to remove the sampling tubes and seal up the insertion points at the end of primary fermentation, so that the conditions during maturation remain unknown.
Keywords : analysis composition cylindro conical tank fermentation green beer pH temperature time wort