Marula Wine Making Process Environmental Sciences Essay

The name chosen for the marula wine produced in this activity is a combination of the first names of both manufacturers. It sounds exotic and thus makes the wine more attractive to potential drinkers.

The Chemical Process of Fermentation

Fermentation is an enzyme-catalyzed chemical process in cells whereby large organic molecules, such as glucose, are decomposed anaerobically. Simpler molecules are produced and energy is yielded (Fermentation, 2010). In the context of industrial fermentation, suitable microorganisms and specified conditions are necessary to begin reactions that produce products such as alcohol and glycerol. During alcoholic fermentation, enzymes from yeasts added to fruits are used to convert sugars and starches into alcohol. Carbon dioxide and energy are also yielded from the reaction (Fermentation, 2008). At the end of the process, yeast or other microorganisms no longer convert sugars in the solution into alcohol. Dead yeast cells will then remain suspended in the wine, which should be removed.

During the manufacture of wine and beer, fermentation is evident in the production of foam, which is the carbon dioxide that is yielded from the reaction. In order to manage the reaction effectively for the best possible outcome, various factors should be carefully controlled. If the temperature of the surroundings is too high or too low, this will kill the yeast. The temperature needs to be approximately between 20 and 25 degrees Celsius for the yeast to thrive (The Fermentation Process, 2007).

If too much sugar is added, a “stuck” fermentation will occur soon after the process starts, due to the inhibition of the yeast (The Fermentation Process, 2007). It will then only be able to tolerate a low concentration of alcohol. The solution should be diluted in order to reduce the sugar concentration and reactivate the yeast. The fermentation may not start if the solution is too acidic, or if there is not sufficient acid. If the fruit solution is too acidic, the wine will taste bitter and should then be neutralized using a potassium carbonate solution. If the wine lacks bouquet and tastes insipid, there is too little acid. Two teaspoons of citric acid should be added per 4, 5 litres of wine (The Fermentation Process, 2007) to improve the taste of the wine.

The taste and bouquet of the wine can negatively be affected by certain elements during the wine-making process. A bacterial infection can easily occur if the mixture has not been properly sealed, or if the wine-making equipment has not been adequately sterilized. The wine will easily acetify and form vinegar as a result of bacterial spoilage. The addition of a small amount of sodium metabisulfite in the early stages of fermentation is necessary to kill all bacteria and thus prevent oxidation and the resulting expiration of the wine. However, the mixture may smell like rotten eggs if too much sodium metabisulfite has been added. It will react with the yeast and cause an excess of sulfites to be released (The Fermentation Process, 2007).

The clarity of the wine will be reduced if the yeast remains suspended in the solution (The Fermentation Process, 2007). The wine should then be moved to a cooler area and potassium sorbate should be added to stabilize the mixture by killing the yeast. A pectin haze may also often occur due to the remaining cellulose from the fruit (How to make homemade wine step by step, 2009). A very small amount of pectin enzyme should be added in due time to decompose the pectin. The wine will then clear after a few weeks. If it lacks colour, there is not a high enough concentration of fruit. Tannin or acid needs to be added and the wine must then be left to mature further. If the wine is too bitter, there is excess tannin due to the high concentration of fruit in the mixture (The Fermentation Process, 2007).

Importantly, carbon dioxide gas should be removed during the fermentation process so that the taste of the wine is not adversely affected by the production of any bacteria. However, if there is too little carbon dioxide, the taste of the wine could also be negatively affected. If the fermentation is still in process when the wine is sealed in a bottle, high levels of carbon dioxide may be dangerous. This may cause the bottle to burst or the cork or seal to be pushed off with great force due to the high pressure created inside the container. It is thus essential to make sure that fermentation has stopped before the wine is bottled. The process should either be allowed to run to completion (no more foam is present), or 1 gram of potassium sorbate should be added to every 4, 5 litres of wine. This inhibits the growth of yeast or other microorganisms that cause fermentation in the solution (The Fermentation Process, 2007).

Procedural design

Aim

To produce 750ml of high quality wine by the controlled fermentation of the fruits of the Marula (Schleracarya birrea) tree.

Hypothesis

High quality wine will be produced by the controlled fermentation of ripe fruits of the Mpumalanga Marula tree.

Abstract

It was decided that a combination of recipes would be used in order to maximize efficiency for the purpose of making Marula wine. No specific recipes for Marula wine were found, but most instructions specified that any fruit from a certain category could be used in the recipe.

4 separate batches of marula wine were made. Each batch was tightly sealed in an opaque container. It was sealed in order to prevent more air and bacteria from entering. In this manner, aerobic bacteria would not survive in the container due to the low amount of oxygen available. The stimulation of bacterial growth by sunlight would also be prevented by the opaqueness of the container.

A small quantity of sodium metabisulfite (Campden powder) was added to each of the wine mixtures in order to kill bacteria and preserve the wine (How to make homemade wine step by step, 2009). This was necessary in order to prevent acetefication due to bacterial infection of the solutions. A hole was made in the lids of each container so that a flexible plastic pipe could be inserted. The end of the pipe was placed in a container filled with water to allow for carbon dioxide gas to escape from the fermenting solution. No other gases were allowed to enter due to the placement of the pipe in the water. This should have further prevented bacteria from growing in the solutions.

The wines were made, sealed and left to ferment on the 31st January 2010. Approximately a month was allowed for the fermentation of each of the wines. The best wine was then selected according to its bouquet, taste, clarity and colour. The very first batch was chosen.

A very small quantity of pectic enzyme was added to the chosen batch after a month at the end of the fermentation process in order to decompose the pectin sediments that remained suspended in the solution. This should have improved clarity, taste and bouquet (Callec, C., 2006)

Wine 1 (Chosen Batch)

Apparatus

±2kg ripened Marula fruit

4, 5 litres warm water

500ml refined white cane sugar crystals

± 30ml Lemon juice

2 x ripe bananas, peeled and cut up

¼ teaspoon sodium metabisulfite (Crushed and powdered Campden tablets)

Pectic enzyme

Large metal pot

Sharp knife

Chopping board

Digital scale

Large airtight, opaque container with small hole for pipe

Dropper

Flexible plastic pipe

Nylon mesh straining bag

Cooking oil filter Paper

2 x Jugs

Sterilized, transparent wine bottle with lid

Stirring spoon

Funnel

Method

Collect ripened (yellow) marula fruit from across the Nelspruit region.

Discard rotten marulas.

Rinse marulas with skins on.

Boil ± 4, 5l water on stove in large metal pot. Add sugar and stir until solvent dissolves.

Allow water and sugar solution to cool whilst peeling marula fruits.

Cut cross in marula skins with sharp knife and peel.

Discard rotten fruit and skins.

Measure mass to obtain approximately 2kg peeled marula fruits.

Add peeled marula fruit and warm sugar solution to large, airtight, opaque container.

Add chopped bananas, lemon juice and sodium metabisulfite to solution.

Stir mixture and make hole in lid.

Seal lid on top of mixture.

Place pipe into container through small hole in lid. Place the end of pipe into the water container.

Place in a moderately warm, dry and dark room.

Allow to ferment for 1 week. Remove marula pips and fruit sediment from mixture.

Ferment for a further 3 weeks, checking every few days for bacterial infections and to make sure that fermentation is progressing properly.

Use dropper to add 1 drop of pectic enzyme to mixture. Fermentation must be complete. Leave mixture for a further 2 days.

Filter mixture twice using cooking oil filter paper, nylon staining mesh and jugs.

Cover and place wine in fridge to cool. Leave for 1 day.

Filter wine once more and use funnel to transfer the wine to sterilized wine bottle. Seal and keep cool in fridge.

Presentation:

The presentation was carefully planned according to appropriate wine-tasting etiquette. A plain white tablecloth and neutral tones were chosen in order to bring focus to the actual colour and clarity of the wine (Callec, C., 2006). Proper, clear wine glasses were used to present the wine. A single white candle was lit so that the clarity could be properly examined. Salticracks and assorted wine cheeses accompanied the wine as a palette-cleanser for the tasters. Tasteful, but simple cheeses were chosen so that the taste of the wine would not be overpowered. A spitting bucket was provided. Quality Marula Wine

Wine batches 2 – 4

Wine 2

500g peeled marula fruit

¼ teaspoon sodium metabisulfite

Airtight container

Wine 3

500g peeled marula fruit

500ml white sugar

2 litres warm water

Airtight container

¼ teaspoon sodium metabisulfite

Pipe

Medium plastic container

Wine 4

1000g unpeeled marula fruit

4 litres water

¼ teaspoon sodium metabisulfite

Airtight container

Pipe

Analysis of results

A large panel of wine-tasters judged Dalroch at a wine-tasting ceremony held at Penryn College on 25 February. The wines were judged according to bouquet, taste, clarity, colour and presentation. Various scientific explanations can be given for the overall results.

Dalroch was lightly tinted in colour. The level achieved for this result was 3/7. This can be attributed to the fact that the concentration of fruit in the wine was too low. The solution was too dilute and the fermentation process did not occur efficiently enough to yield a wine with an intense, attractive colour. No wine yeast was added to the mixture, which would most certainly have had a detrimental effect on the fermentation procedure. The reaction would thus have been very slow or even stunted due to the lack of microorganisms to decompose the Marula fruit. Some fermentation may have occurred as a result of decomposition organisms in the Marulas, but not efficiently enough to yield an intensely attractive colour in the wine. Due to the preservation of the solution by sodium metabisulfite, the initial light, white colour that the marulas produced would have been maintained.

The result obtained for the clarity of the wine was 5/7. There was no sediment in the wine, as pectic enzyme was added 3 days prior to the wine tasting. But the cloudy colour can be attributed to the fact that the pectic enzyme was added too late for proper decomposition of the pectin sediment to occur. The cloudy wine was also most likely as a result of bacteria spoilage. The equipment used may not have been sterilized properly, resulting in bacterial infections of the wine (The Fermentation Process, 2007). The solution was most probably oxidized because the container was not properly sealed to prevent air from entering. The container was opened too often, allowing bacteria to enter and reproduce in the wine mixture. The cloudy haze of the wine could also be attributed to the fact that fermentation did not occur properly, due to the omission of yeast in the mixture. The fruit would therefore not have reacted sufficiently with microorganisms to produce alcohol, leaving more sediment in the wine (The Fermentation Process, 2007). The slight cloudiness of the wine could not have been caused because the solution was not filtered properly. It was filtered enough times using proper filter paper and a nylon mesh bag.

The result received for the bouquet of Dalroch was 4/7. The smell of the wine was slightly unattractive. Bacterial infection of the wine would have caused it to acetify, giving it an unpleasant smell akin to that of vinegar (The Fermentation Process, 2007).

The wine tasted slightly like vinegar. Bacterial infections caused by improper sterilization of equipment and oxidation of the wine after exposure to air would have caused the wine to have a slightly sharp, unpleasant taste. The sodium metabisulfite that was added at the beginning of the procedure would have prevented the wine from acetifying further by killing most bacterias. More sodium metabisulfite could later have been added to help preserve the wine and prevent further acetefication (Callec, C., 2006). The sharp taste can also be attributed to the poor fermentation of the fruit. Insufficient microorganisms for reaction with the fruit sediment to produce alcohol would have resulted in insufficient and stunted fermentation. The prevalence of pectin sediment would have given the wine a very astringent taste due to the acidity of the tannin in the cells of Marulas. This problem could have been resolved by neutralizing the acidity with a potassium carbonate solution (The Fermentation Process, 2007).

Because the presentation was properly planned according to the rules of wine-tasting etiquette, good results were received. However, it may have been improved by using music and a slide-show to create more ambiance.

Failed wines:

Neither of batches 2-4 was successful. Each had a notably bitter taste and an unattractive smell. Batch 4 was the least attractive. This can easily be attributed to the addition of skins to the mixture and bacterial spoilage. The levels of pectin and tannin were very high and the astringent solution was also very hazy. The heavy bitterness was thus as a result of acetefication and high acidity in the mixture. The clarity could have been improved with the addition of pectic enzyme to decompose the pectin sediment. Potassium sorbate could have been added to stunt fermentation and prevent too much alcohol from forming.

No sugar was added to the second or forth batches. It can be deduced that insufficient nutrients were thus available to the microorganisms in these mixtures. Fermentation would not have occurred properly, even though some sugars from the fruits were available for the reaction. The very unpleasant tastes could have also been attributed to bacteria spoilage in the wine (The Fermentation Process, 2007).

Evaluation of Process

A more successful result could have been obtained if the wine-making process was planned more carefully prior to the making of the wine. The equipment could be sterilized properly in future to prevent initial bacterial infection and acetefication of the wine. A proper airlock could be used to prevent the entering of air into the fermenting solution. Bacteria would thus be prevented from reproducing and oxidation of the wine would not occur. Wine yeast should have been added so that the fermentation process would have been carried through properly, producing enough alcohol at a fast enough rate (The Fermentation Process, 2007). The pectic enzyme should be added a few weeks prior to the completion of the wine so that the pectin sediment could have been decomposed properly. The clarity of the wine would thus improve. Sodium metabisulfite could be added every two to three weeks to kill all bacteria and inhibit acetefication of the wine. Small amounts would be used to prevent the wine from smelling too sulfurous. At the end of the procedure, one gram of potassium sorbate would be added to the wine to stunt further fermentation and production of carbon dioxide. By doing this, the bottle would be in no danger of bursting (The Fermentation Process, 2007).

Conclusions

The quality of the wine produced by fermentation of Marula fruits was average. Fermentation was not controlled properly, resulting in bacteria spoilage and the consequential acetefication of some of the solution. Due to the omission of yeast and inadequate preservation of the solution, a stunted fermentation resulted early in the production process. It can therefore be concluded that the attempted control of fermentation of Marulas fruits was not effective, resulting in a wine of mediocre quality. The fermentation process should be controlled better in future to produce a higher quality wine.

Uses of alcohol in our multicultural society

“Alcohol is a drug that affects the central nervous system. It belongs in a class with the barbiturates, minor tranquilizers, and general anesthetics, and it is commonly classified as a depressant”. (Alcohol consumption, 2010).

Alcoholic beverages are consumed in our multicultural society largely for their effects on the mind and body. Alcohol is often utilized within certain social contexts and even as a part of some religious practices (Alcohol consumption, 2010), as it is closely associated with enjoyment and as having symbolic value in celebrations. The effects of alcohol on the brain and body may vary greatly. For some, the substance may serve as an excitant. Under other conditions it can act as a sedative. When consumed as a beverage in high concentrations, alcohol becomes a depressant. This most often leads to a stupor and in more severe situations, coma (Alcohol consumption, 2010).

As a food, alcohol effectively has very little nutritional value beyond its caloric content. However, people in general society drink alcohol to reduce feelings of tension and anxiety and often to experience exhilaration. Many discover that drinking can help to suppress overwhelming inhibitions and tensions that interfere with the need to function effectively in social or economic situations. The anxiety-suppressing action of alcohol is largely due to a function of muscle relaxation and the removal of social inhibitions. Alcoholic beverages are used to cause a loss of socially expected restraints. The shy become outgoing or bold. Well-behaved people become disorderly and fearful people may become brave. In most modern societies today, the capacity of alcohol to serve as a social aid is valued greatly. (Alcohol consumption, 2010).

 Alcohol is important in pharmacology for use as a solvent for some active, more non-polar medicines (Alcohol consumption, 2010). Such medicines are not very soluble in water, which is comprised of polar molecules. These substances would more readily dissolve in alcohols, which are comprised of polar and non-polar parts. Alcohols with larger alkyl groups would be most preferable for non-polar medicines, as these are more non-polar than alcohols with smaller alkyl groups.

It has been scientifically proven that alcohol can act as a mild anticoagulant and reduce the risk of strokes and heart attacks, when just 15ml is consumed per day. The substance is also used for the prevention of what is known as delirium tremens (symptoms due to alcohol withdrawal) in alcoholics (Alcohol consumption, 2010). In some cultures, whiskey is used to treat colds and snakebites. Brandy is used to treat faintness. Spirits can be used as a tonic, beer for lactation and any other alcoholic beverage for the treatment of tiredness or overexcitement. However, these uses depend largely upon popular belief and not on sound medical fact. Physicians may prescribe an alcoholic “drink” to stimulate a sluggish appetite, to act as a vasodilator and to relieve premenstrual stress in women. Alcoholic beverages can be used to relieve aches and pains in elderly people (Alcohol consumption, 2010). However, these effects are once again more psychological than medically effective.

Alcoholic beverages most often become central in important personal and social ceremonies. These include rites of passage in most religions and all African cultures, medicine, birth ceremonies, initiations, weddings, feasts, conclaves, crownings, magic rites, worship rituals, hospitality, war declaration, peace declaration and funerals (Alcohol consumption, 2010).

In the earliest agriculturally dependant civilizations, alcoholic beverages had many uses. Firstly, they had nutritional value. Secondly, they were the most efficient kind of medication available to treat certain illnesses and particularly for relieving pain. It would have had the capacity to help the shaman or priest and other participants to reach a desired state of ecstasy or frenzy to be able to “communicate” with supernatural spirits or gods. The substance’s “powers” were attributed to the supernatural. Alcohol is still used in “magic” ceremonies in African cultures today due to the continuation of such beliefs. As in modern society, alcohol was used in keystone ceremonies and allowed for more enjoyable festivities. Ancient uses of alcohol have influenced its role in society today. A drink is still used symbolically to announce friendship, peace, agreement and used in business of political relations.

In Judaism, consumption of alcohol is important in the celebration of circumcision of 8-year-old boys to celebrating weddings, toasting to the departed in funerals and on every Sabbath day. In these kinds of ceremonies, alcohol became synonymous with a strict attitude of respect for the importance of such occasions. Drinking too much is consequentially inappropriate. Becoming drunk in any social situation has thus become a rejected and negative practice (Alcohol consumption, 2010). In many other religions, red wine is used religiously to symbolize the blood of life and, in Christianity, to symbolize the blood of Jesus Christ (Alcohol consumption, 2010).

In Islam, the Koran condemns the drinking of wine. Consequentially, devout followers of Mohammed all over the world have strictly prohibited the use of any kind of alcoholic beverage at all. Similarly, some Christian denominations have also attested to the prohibition of alcohol consumption due to the detrimental effects it can have on behavior and the body. It is believed that loss of inhibition caused by drinking is disrespectful to the body and to the God in question (Alcohol consumption, 2010).

In South Africa and on the rest of the continent, maize, sorghum, bananas, honey, certain tree saps and many fruits have been fermented to produce a variety of exotic beers and wines. In the Zulu culture, for example, beer is made by the female and used to celebrate successful hunting trips or won battles by the males. It is also used by the Shaman and its consumption is not strictly controlled in these cultures (Alcohol consumption, 2010).

 The South African government has shown recognition of the potential of newer, science-orientated approaches to alcohol use. Research, education and therapeutic activities are supported, often through special institutions. This is done to maximize control of alcohol use in our society today. (Alcohol consumption, 2010).

Conclusively, the reasons for alcohol use can be summarized by its function as a facilitator of mood change in any desired direction.

Abuses of alcohol in society

Alcohol is commonly discussed in terms of its detrimental effects. The most serious and negative effect of alcohol on humans is alcoholism. The next most serious problems that may be caused are alcoholic diseases. Physical and mental problems arise directly or indirectly as a result of alcoholism or heavy drinking. Due to the negative effects that alcohol can have on the body and because of how it influences behavior when consumed in copious amounts, governments regulate its use by enforcing laws (Alcohol consumption, 2010).

In South Africa and the rest of the world, there has been a steady increase in the amount of alcohol consumed over the last century. This has resulted from an increased availability and accessibility of commercial alcohols. Advertising has played a large role in the higher consumption and consequential abuse of alcohol in our society today (Parry, C.D.H.; Pluddemann, A., 1998). In modern society, social pressure can often cause people to abuse alcohol in order to “fit in” and become socially acceptable to their peers. This is considered highly problematic due to the severe and varying consequences that alcohol has on the mind and body, particularly when it is consumed in large quantities. The most common problems that arise are “hangover” effects, which include headaches, nausea, dizziness, gastritis and dehydration. Physical and mental incompetence may last as long as 24 hours after the alcohol consumed has been metabolized. Frequent or heavy intoxication of the body by alcohol can cause severe disturbances to one’s health. These disturbances may include cardiac arrhythmias, acute hepatitis, loss of memory, fainting, cancer of the esophagus, stomach and other organs, and other mental impairments which arise in the long-term due to the eventual shrinking of the brain (Alcohol consumption, 2010).

Living in our society today comes with the heavy, unavoidable burdens of stress that are brought about by fast-paced, busy and unhealthy lifestyles. It has been scientifically proven that the rate of depression across the globe has increased very significantly as a result (Alcohol consumption, 2010). Many people choose to consume alcohol in order to escape from the reality of their social pressures. This often leads to abuse of the substance. Some drinkers who feel more socially acceptable when drinking are willing to suffer mild and even the severe aftereffects of drunkenness for the sake of temporary euphoria and loss of inhibition. Frequent intoxication, even of a moderate degree, has a severe and burdening effect on the drinker. It can cause severe liver damage and atrophy of the cerebral cortex in more vulnerable people (Alcohol consumption, 2010).

It is often seen that the alcoholic experiences more social problems than the expected relief for which they drink. Due to the mental and physical impairment that alcohol causes when consumed in heavy amounts, alcoholics cannot function properly in the simplest of daily activities. For this reason, many alcoholics experience job loss and social rejection. The abuse of alcohol can cause serious aggression and result in verbal, physical and sexual abuse of others. The alcoholic will consequentially alienate even the people that matter most to them. Alcohol may be seen as the single greatest cause of the breakdown of family life (Alcohol consumption, 2010). If the problem is not attended to, poverty and even eventual death may result.

The social and economic costs of alcoholism and heavy drinking are heavy in societies all over the world. The annual costs of serviced provided due to these problems are measured in billions of dollars (Alcohol consumption, 2010). A large fraction of the work of police departments and the cost of local courts and jails is attributed to arrests and prosecutions for public intoxication and other incidents in which alcohol is involved. It has become very necessary for governments to intervene in order to maintain some control over the use of alcohol in society today (Alcohol consumption, 2010).

The drinking age in South Africa is 18 years by law, and it is illegal for any establishment to sell or provide alcohol to a minor. The government regulates this law due to the higher abuse of alcohol by more irresponsible adolescents and because of how studies show that alcohol consumption and abuse is skewed towards younger populations. Alcohol intoxication is closely associated with mortality and morbidity that are caused mainly by accidents and violence. According to Mr Jacob Zuma, alcohol has been associated with unsafe sexual practices and an increased risk of contracting HIV (Parry, C.D.H.; Pluddemann, A., 1998). In developing countries all over Africa, infectious diseases remain very viable causes of alcohol misuse. Studies associate this with poor nutrition and it can therefore be deferred that the consequential weakening of the immune system by such practices further increase susceptibility to opportunistic diseases (Parry, C.D.H.; Pluddemann, A., 1998).

One of the most serious abuses of alcohol is drunk driving. It is illegal in South Africa to drive whilst the concentration of alcohol in any sample of blood taken from the driver is more than 0, 05 grams per 100 millilitres (Alcohol and Legal Implications of Drunk Driving, 2007). Alcohol mentally and physically affects the driver by causing their reactions to become sluggish and judgment of other vehicles and objects on the road to become impaired. Due to high speeds and the much higher chances of causing a collision on the road, it is a very serious offense to drive drunk. The lives of the driver many innocent people on the roads are endangered due to drunken driving and negligence that is so common amongst people in society today. The “Arrive Alive” campaign on roads is one of the many examples of attempts by the South African government to reduce and effectively end the abuse of alcohol and the consequential increasing death toll on our roads (Alcohol and Legal Implications of Drunk Driving, 2007).

There is evidence that an expectant mother can endanger the development of the fetus by drinking even the smallest quantities of alcohol. Fetal alcohol syndrome may result from a variety of birth defects that arise as a result. The problem arises when people do not take medical advice seriously. Some negligent mothers are abusive to the lives of their children by consuming alcohol during pregnancy. The defects include disorders of the central nervous system, slower development, mental impairment and abnormal physical features. Some babies are so severely affected that they may die soon after birth. No amount of alcohol consumption should thus be considered safe during pregnancy (Alcohol consumption, 2010).

It can be concluded that the abuse of alcohol in our multicultural society today should be avoided due to the many serious and negative implications that are associated with its intoxication of the body. It is essential for the governments of all countries to strictly regulate consumption for a safer, more efficient and productive society.