Wine Quality Essay

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Background: FACTORS AFFECTING WINE QUALITY The quality of wine is determined by a number of interrelated variables which take effect during the fermentation process. The variables that have the most significant effect are as follows; the pH of the wine, the temperature at which the fermentation process is transacted, the alcohol and CO2 percentage present post fermentation, the amount of SO2 (sulphur dioxide) present in the solution and the wines titratable acidity. Overview of each variable: The pH is a measure of the amount of acids present in the solution, it differs determining on the strength of these acids and may also change depending on the other miscellaneous ingredients added to the wine with any degree of acidity. For wine specifically, …show more content…

Because fermentation is an exothermic process (releases heat) it must be kept under constant surveillance. The temperature in which the formation process is heated controls the different tastes of wine (from fruity to artificial). For Red wines, the optimal temperature concludes at 25-300C (this includes the heat released from the fermentation process) in which yeast is fermented at its maximum and most efficient rate (because of particle movement). Post the fermentation process, the amount of alcohol present is a main control of the taste and quality of each wine; creating preference. Fermentation (more specifically ethanol fermentation) is the process in which pyruvate (from glucose metabolism (carbohydrates)) is broken into carbon dioxide (CO2) and ethanol (alcohol), the presence of yeast and certain bacteria aids this process which occurs usually under anaerobic conditions. The chemical equation for the fermentation process is as …show more content…

The formation of SO2 is what’s classified as a strain characteristic, and holds two purposes, the first is in the process of wine making is to inhibit the growth of unwanted yeast or bacteria during fermentation as well as inactivating certain enzymes during this process. The second purpose is to act as an antioxidant. Because of this it can protect the wine against browning and allow it to sustain its integrity for longer periods of time. When Molecular SO2 is present in wine it acts as a form of pesticide effectively killing the wine microbes. Fortunately however the yeasts that are considered desirable which are fermented have a resilience to the effects of SO2 then that of spoilage yeasts. Sulphur dioxide can also exist in an ionised form when simply dissolved into wine. In this form it has the greatest antioxidant effect. Because, instead of joining with oxygen directly, sulphur dioxide joins with other antioxidants it proceeds to remove all naturally occurring enzymes causing the wine to brown (known as polyphenol oxidases) which gives the wine a sustainability which would not be present without the sulphur

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