Marula Fruit Experiment

Practical Investigation:

Marula Wine Experiment

Angus McQueen

Introduction:

Chemical Process of Fermentation of Marula Fruit:

The fermentation of alcohol involves converting large organic molecules (such as carbohydrates and glucose) into more straightforward molecules, like alcohols and carbon dioxide. For fermentation to occur bacteria and yeast are needed. There should be anaerobic conditions for the process to occur. This means that the process occurs without air. Therefore oxygen may not be used in this process. Fermentation is an exothermic reaction where heat is given off as a result of the reaction that occurs.

During the alcoholic fermentation a basic reaction occurs:

Sugar + Yeast Enzymes = CO2 + Alcohol

The

The predominant factor that should be controlled is the temperature. If the temperature readings are too low or too high the yeast will be break down thus preventing fermentation from occurring.

During the production of alcohols, sugar is converted into carbon dioxide. This can be seen as a foam layer that resides on the top. As soon as the bonds in the sugar break down, carbon dioxide forms and bubbles through the solution. It is here where it is lost in the atmosphere. This then allows the alcohol to remain in the solution. An excess of alcohol in the solution causes the yeast to die.

Hypothesis:

The addition of artificial ingredients will degrade the quality of a marula wine.

Method:

Ingredients for Wine A: (Use of artificial ingredients)

• 2.5 Kg ripe marulas

• 1.5 Kg white sugar

• ½ a teaspoon of sodium metabisulphite

• 2.5 Litres of water

• 20 Grams of Brewer’s yeast

• 1 tablet vitamin B Ingredients for Wine B: (Use of natural ingredients)

• 2.5 Kg ripe marulas

• 250 ml of water Method for wine A: (artificial

There was not enough time for the process to ferment fully. Lack of research prior to the experiment is the result of a few failed attempts in the process of making the wine. Other than that there was little to no experimental error.

Recommendations for improvement:

• Score the two different wines separately in order to compare them. This is to decipher which method is proven more successful.

• Time is a very important aspect, more time was needed for the fermentation to take place. With a limited time frame our wine could not ferment fully therefore resulting in the below average scores for colour and clarity. Therefore a longer fermentation period is recommended.

Conclusion:

The addition of artificial ingredients did degrade the quality of the wine. This is because the marula fruit is sweet as it is and the addition of artificial ingredients just made it too sweet. The wine with the natural ingredients tasted better because of this.

Front and back view of the