Commissioning and optimisation of Wits Micro-Brewery Plant.

Abstract

The Brewing Industry is facing increasingly challenging times due to global competitive business environment and rising costs of raw materials. These factors consequently affect the economy of the industry. An effective solution to stay competitive is to enhance brewing process efficiency by optimisation of process units. The aim of the study was therefore to investigate optimal operating conditions that can be implemented in the brewing industry using the Micro- Brewery Plant at the University of the Witwatersrand. It was discovered that the longer the mashing route, the higher the yield of fermentable sugars. The mash regime and liquor to malt ratios were optimised and the carbohydrates obtained were analysed at 3.5 L of water per kg of malt and a total mash time of 105 min. Carbohydrate and phenolic acid analyses were performed by High Performance Liquid Chromatography (HPLC) coupled with a UV-vis detector. The three different malts used had a phenolic acid content of 33.25μg/mL, 25.44μg/mL and 19.98μg/mL for malt A, B and C, respectively. The plot of 1/T versus Ln(t) gave a negative slope with activation energy (Ea) = 209 KJ/mol, rate constant (k) = 4.6 x 10-4 mg/L min, which are comparable to similar data reported in the literature. The kinetics studies showed that the optimised mashing temperature of 900C was adequate to form 4-Vinylguaiacol by thermal decarboxylation from the hydroxycinnamic acids. This study has shown that there is no direct correlation between phenolic acids and oxidative flavour stability of beer while the corresponding volatile phenols may affect beer flavour. The study showed that fermentation rates increase with temperature. Investigated pitching rates showed iv insignificant effect on fermentation rates. The study showed that added finings during boiling improve beer clarity and have an insignificant effect on fermentation rates. Analysis of commissioning strategies at Wits micro-brewery plant showed that verbal instruction is always open to error, while the written instruction or report is generally not open to error. Hence the commissioning documents have been developed in the study, which has helped in reduction of errors during brewing. It is therefore concluded that good record keeping and documentation is of essential need for successful commissioning of a brewery.