Throughout the course of this Investigation, how sugar influences the rate of fermentation and how this in turn, affects the overall quality of wine was explored. Three wines were produced, each with varying sugar levels. The Investigation was designed so that one wine had a fairly low sugar content; one had an ideal sugar content and one had a high sugar content. After the fermentation process stopped, a taste test was conducted in order to assess the quality of the wine. The taste testers were blindfolded in order to reduce the chance of biased opinions. Each taste tester not only sampled each wine, but also sugar water and tonic water. This enabled the validity of the results to be assessed. It was found that the majority of the conclusions drawn by the taste testers were legitimate.
During the fermentation process, the yeasts that were initially added to the wine reproduce, via asexual reproduction. Theoretical research has concluded that this is dependant on the sugar content of the wine. The higher the sugar content of the wine, the greater the rate of reproduction. When yeasts are exposed to anaerobic conditions, yeast is able to undergo fermentation, the process by which grape juice becomes alcoholic. Energy is essential to this process. The necessary energy that is required is produced via anaerobic respiration.
Glucose + Oxygen Carbon Dioxide + Water + Energy
C6H1206 + O2 CO2 + H20 + Energy
Figure 11: equation for anaerobic respiration
Author Unknown, 2010
Therefore the greater the amount of sugar (glucose- C6H1206) inputted into the wine, the more energy that it is able to be produced. This energy produced is transferred to the yeasts, providing the necessary energy needed to reproduce. This inturn creates an alcoholic wine. The experimental results supported this theoretical research. During the Investigation, the sugar levels decreased. This was because the sugar was being converted into carbon dioxide, water and most importantly, the energy required by the yeasts. Further supporting the research, it was found that Wine C, the wine with the greatest alcohol content, experienced the greatest change in sugar levels throughout, the next highest was Wine B and then finally Wine A, the wine with the least amount of sugar. The taste test that was conducted also supports this information, with the majority of the taste testers concluding that Wine C had the greatest alcohol content of the wines, followed by B and finally A.
Although, it is the yeasts present in wine that increase the alcoholic content, yeasts have a certain tolerance level of alcohol; and once this level is exceeded, the yeasts die and are no longer able to reproduce. Theoretical research has concluded that the tolerance level of yeasts is a 14% alcoholic content, any level higher than this would cause the yeasts to die off. The wines that were produced during the Investigation, had predicted alcohol levels...