Commissioning and optimisation of Wits Micro-Brewery Plant.
Date
2010-02-04T12:40:38Z
Authors
Madigoe, Ezekiel Makwadinkga
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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
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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.