CONCLUSION AND RECOMMENDATIONS

It can be stated, that the water to malt ratio and the mashing route can influence the concentration of malt extracts. Increasing the mashing water of the ratio (water, L: malt, kg) increases the concentration of fermentable carbohydrates, but only up to certain optimum point where extractable sugars have dissolved and the concentration decreases when more water is added. From the mashing routes investigated it can be concluded that the longer the mashing time, the more fermentable carbohydrates are extracted.

From the malts studied which had different phenolic acid amounts, it can be concluded that different amounts of phenolic acids have same effect on oxidative flavour stability of beer. From the observation of beers produced from malts with different phenolic acid content, it can be concluded that phenols are responsible for haze formation in the appearance of beer. There are many different mashing systems that can be used; hence the investigation has shown that various things need to be taken into consideration when designing mashing profile.

Values up to 1.45 ppm p-coumaric acid, 13.10 ppm ferulic acid, 4.65 ppm sinapic acid, 2.70 ppm 4-vinylphenol and 4.37 ppm vinylguaiacol ^[51] are common concentrations of phenolic compounds in beer. Meilgaard ^[52] reported that the flavour threshold in beer is 52 ppm for p-coumaric acid, 66 ppm for ferulic acid (FA) and 0.3 ppm for vinylguaiacol. Hence, in this study where the phenolic compound concentrations ranged

from 0.18 ppm syringic acid in Malt A, to 23.68 ppm p-hydrobenzoic acid in Malt A, they exist within the range reported. Thus 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 concentrations of most of the phenolic compounds detected in the study should contribute to the sour, bitter and astringent flavours that may be associated with beer prepared from Malt A, B and C.

The results obtained in this study provide information that is necessary in the control of the quality and stability of beer. Since the low molecular weight phenolic compounds may affect the sensory properties of the beer, the choice of variety and processing conditions are important in determining the quality of the beer.

Fermentation rates increased with an increase in temperature. Hence was concluded that optimised fermentation rates can be achieved by increasing fermentation temperature within such range when the cells remain viable. Clarity of beers increased with an increase in finings up to a certain point, and finings show a slight effect on fermentation rates. The results obtained in the study helped to locate the optimum amount of kettle finings for beer clarification. Pitching rates investigated showed an insignificant effect on fermentation rates, from the study it was concluded that fermentation rates are affected by significantly high pitching rates.

Developed commissioning documents helped in reduction of errors during brewing, hence it was concluded that good record keeping and documentation is of essential need for successful commissioning.

The following are recommended for further studies:

• Increase the difference in phenolic acid content among different malts by addition of external phenolic acids because it is suspected that the difference in phenolic concentration among our samples was miniature to certain extends.

• Investigate other methods and or procedures or conditions that can be used to detect the phenolic acids in wort and beer with higher precision to prevent major losses in phenolic bounds. Addition of ascorbic acid, antioxidant, and ethylenediaminetetraacetic acid (EDTA) and a metal chelator can completely prevent the loss of phenolics.

• Further studies are necessary to determine the metabolism of the phenolic compounds by lactic acid bacteria and yeasts involved in the preparation of the fermented beverage and the effects of any metabolites on overall beer quality and stability.

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