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Contents1.0 Abstract:................................................................................................................................4

2.0 Introduction:..........................................................................................................................5

2.1.0 Control hypothesis:............................................................................................................8

2.1.1 Variable hypothesis:..........................................................................................................8

2.2.0 Aim:....................................................................................................................................9

3.0 Risk Assessment:..................................................................................................................10

4.0 Materials: Must making.......................................................................................................13

4.1 Materials: Into the Fermenter.............................................................................................13

4.2 Materials: Sugar calculations...............................................................................................13

4.3 Materials: Racking the wine.................................................................................................13

4.4.0 Materials: Using a hydrometer........................................................................................14

4.4.1 Materials: Using a refractometer....................................................................................14

4.4.2 Materials: Using a multiparameter..................................................................................14

4.4 Materials: Acid-base titration..............................................................................................14

4.5 Materials: Assessing sulphur dioxide titration.....................................................................14

4.6 Materials: Concentration of alcohol titration......................................................................15

4.7 Materials: Aerating the variable wine..................................................................................15

5.0 Method: Must making.........................................................................................................16

5.1 Method: Into the Fermenter................................................................................................16

5.2 Method: Sugar calculations.................................................................................................17

5.3 Method: Racking the wine...................................................................................................17

5.4.0 Method: Qualitative tests- hydrometer...........................................................................18

5.4.1 Method: Qualitative tests- refractometer.......................................................................18

5. 4.2 Method: Qualitative tests- multiparameter.....................................................................18

5.5 Method: Acid-base titration.................................................................................................18

5.6 Method: Assessing sulphur dioxide titration.......................................................................19

5.7 Method: Concentration of alcohol titration.........................................................................19

5.8 Method: Aerating the variable wine....................................................................................20

6.0 Results:................................................................................................................................21

6.1 Figure 1- Control wine results..............................................................................................21

6.2 Results: Figure 2- Variable wine results...............................................................................21

6.3.0 Figure 3- Hydrometer for control wine............................................................................22

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6.4.0 Figure 5: Control wine Brix vs. Ebulliometer....................................................................22

6.4.1 Figure 6: Variable wine Brix vs. Ebulliometer...................................................................23

6.5.0 Figure 7: Salinity in control wine vs. variable wine..........................................................24

6.6.0 Figure 8: pH in control wine vs. variable wine.................................................................24

6.7 Figure 9: Ebulliometer results..........................................................................................25

7.0 Discussion:...........................................................................................................................26

8.0 Conclusion:..........................................................................................................................28

9.0 Appendices:.........................................................................................................................29

9.1 Reading a hydrometer:........................................................................................................29

9.2 Sugar calculations:...............................................................................................................30

9.2.1 Specific gravity correction table:......................................................................................30

9.2.2 Potential alcohol content table:.......................................................................................30

9.2.3 Our sugar calculations:.....................................................................................................31

9.2.4 Continued sugar calculations:..........................................................................................31

9.3.0 Calibrating refractometer scale:......................................................................................32

9.3.1 Refractometer scale example:.........................................................................................32

9.3.3 Labelled refractometer diagram:.....................................................................................33

9.4 Free sulphur dioxide quantities:..........................................................................................33

9.5.0 Titration calculations- Total mass of sulphur dioxide:......................................................34

9.5.1 Titration calculations- Titratable acid:.............................................................................35

9.5.2 Titration calculations- Concentration of alcohol:.............................................................36

9.6.0 Labelled multiparameter:................................................................................................37

9.6.1 Our multiparameter:........................................................................................................37

9.7.0 Aerating the variable wine- aerating machine.................................................................38

9.7.1 Aerating the variable wine- muslin lid.............................................................................38

9.8.0 Adding sugar to the must:................................................................................................39

9.8.1 Adding starter bottle to the must:...................................................................................39

9.9.0 Industrial gas trap:...........................................................................................................40

9.9.1 Balloon gas trap:..............................................................................................................40

9.9.2 Degrees to alcohol percentage conversion wheel:..........................................................41

10.0 Bibliography.............................................................................................................................42

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1.0 Abstract:

The fruit used in this investigation were canned pineapple and canned lychees, which were both in natural juices, and fresh strawberries. Various analytical tests, such as the usage of an Ebulliometer, hydrometer, refractometer and a multiparameter, were performed on the wine through its production to compare it those made in industry. Oxidation was chosen as a variable that was carried out on a small quantity of the wine, while the majority was left as the control to compare the difference in results that the variable caused. The results weren’t substantially different, which is believed to be because potassium metabisulphite was added to the variable wine, which helps to prevent oxidation from occurring. The final alcohol concentration recorded for the variable wine was 13.3% and the control wine was 13.7% so there was a difference of 0.4% alcohol. Oxidation didn’t quantifiably affect the specific gravity because the level of sugar in the wine can’t be altered by oxygen but oxygen can combine with glucose in aerobic respiration in which ethanol is not produced. Slight differences between the two wines were noticed in the pH values and the other multiparameter results.

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2.0 Introduction:

Wine is an alcoholic beverage that is typically made from the fermentation of grapes into either white or red wine (Smith, Monteath, Gould, & Smith, 2009). However wine-like drinks can be made from other types of fruit, which should be referred to in the name, such as; strawberry wine, because the word ‘wine’ by itself is technically and legally defined as grape wine (Smith, Monteath, Gould, & Smith, 2009). Wine production has become substantially more popular in Australia since it was introduced shortly after the First Fleet in 1788 (Smith, Monteath, Gould, & Smith, 2009). The Queensland Government supports the wine industry and there are many guidelines and laws regarding wine production (Smith, Monteath, Gould, & Smith, 2009).

The fruit used in this investigation included canned pineapple and canned lychees, which were both in natural juices, and fresh strawberries. The natural sugar within these fruits allows alcohol to be produced through the process of fermentation, which produces ethanol and carbon dioxide from glucose in the following equation: C6H12O6 2 CH3CH2OH + 2CO2 + 115kJ/mol (Smith, Gould, Monteath, & Smith, 2009). This is an anaerobic equation because fermentation doesn’t require oxygen and, in high concentrations, it is actually toxic to the yeast (Jacobs, 2007). However, yeast may still produce ethanol in the presence of oxygen if they are supported with good nutrition (Jacobs, 2007). Yeast needs sugar and energy to survive and aerobic respiration produces nearly 25 times the energy of anaerobic, which is seen in the following equation: C6H12O6 + 6O2 6H2O + 6CO2

+ 2830kJ/mol (Smith, Gould, Monteath, & Smith, 2009).

During both anaerobic and aerobic respiration carbon dioxide (CO2) is produced so to avoid potentially harmful pressure building up in the fermenting vessel, a gas trap should be used (Deeds, 2013). This will allow carbon dioxide to escape but will not allow the entry of oxygen, which could spoil the wine. If an industrial gas trap is not available, a balloon can be put over the neck of the fermenting vessel and the carbon dioxide released will cause it to expand so if the balloon hasn’t inflated within 24 hours it may be an indication that the yeast isn’t active (Deeds, 2013).

Ethanol is only produced in anaerobic respiration but the yeast requires aerobic respiration for survival because of the energy efficiency (Deeds, 2013). As well as allowing aerobic respiration to occur, oxygen is useful in wine making as it stops excess hydrogen sulphide (H2S), which is a natural by-product from yeast in the process of fermentation (Zoecklein, 2003), from spoiling the wine and producing a foul smell by combining with it in the following equation: 2H2S(g) + 3O2(g) 2SO2(g) + 2H2O(g) (Dharmadhikari, 2010). However, in the presence of oxygen, phenolic compounds, which are made of chemical compounds that affect the colour, taste and texture of wine (James A Kennedy, 2002), become oxidised and the quinones (organic compounds) produced may then form brown polymers (Ribereau-Gyon, 2000). One of the by-products of this reaction is hydrogen peroxide (H2O2), which is an even stronger oxidising agent than oxygen (Ribereau-Gyon, 2000). Sulphur dioxide (SO2) can be added to the wine because it reacts with the hydrogen peroxide to stop any further harmful oxidation (Ribereau-Gyon, 2000). Adding sulphur dioxide preserves the freshness and flavours in the wine because oxygen can cause the loss of the natural fruity smell to that of vinegar and cause the taste to become more “nutty” (Dharmadhikari, 2010). Sulphur dioxide also hinders unwanted yeasts and bacteria (Plant, 2001) that thrive amid abundant oxygen

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(Dharmadhikari, 2010). Sulphur dioxide can be added through a few different methods but in this investigation Campden tablets, which are made of potassium metabisulphite (usually either 0.44 or 0.55 grams), or the powder form of this will be used (Smith, Monteath, Gould, & Smith, 2009).

In industry, the concentration of free sulphur dioxide should be calculated before adding more to ensure the right amount is added because too little won’t sufficiently prevent oxidation or microbe development and too much can cause a foul smell, known as rotten egg gas (Smith, Gould, Monteath, & Smith, 2009). The total sulphur dioxide content can be discovered through titration (see method 5.8) and is made up of the free sulphur dioxide and bound sulphur dioxide, which is combined with sugars and other compounds so it doesn’t have the same antioxidant and antibacterial effect (Smith, Monteath, Gould, & Smith, 2009). However, in Australia there is a legal limit on the total sulphur dioxide; 250mg/L in a dry wine (<35g/L sugar) and 300mg/L in a sweet wine (>35g/L sugar) and to be labelled “preservative free” there must be less than 10mg/L because some people may suffer an allergic reaction if the concentration is higher (Smith, Gould, Monteath, & Smith, 2009).

The amount of free sulphur dioxide within the wine can also be affected by the pH (Kearney & Bogolawski). The optimum pH for white wines is generally between 3.0-3.3 and between 3.4 3.5 for ‐red wines but this may slightly differ depending on the type of wine, however, wines are prone to spoilage and chemical instability when the pH rises above 4.0 as bacteria can reproduce in these conditions (Kearney & Bogolawski). Wine is more likely to stay fresher for longer and maintain its initial flavour and colour in the lower pH range (Kearney & Bogolawski). The freshness of the wine is related to yeast fermentation, oxidation, bacteria growth and fermentation, and protein stability, which are all impacted by the pH (Kearney & Bogolawski).

If the pH is becoming too high, it can be lowered by adding tartaric acid and thus the total acidity is increased (Smith, Monteath, Gould, & Smith, 2009). The total amount of acid in a wine is called titratable acidity, which is the concentration of both free and bound hydrogen ions (H+) and should ideally be between 6.5-8.5g/L (Smith, Monteath, Gould, & Smith, 2009). This can be determined through an acid-base titration in which the wine is titrated with sodium hydroxide solution until the equivalence point is achieved, which has a pH between 8.0- 8.4 (Hammond & McGraw, 2007). From there the mass of tartaric acid can be determined through calculations (see method 5.7) because in industry, it is assumed that the only acid contributing to the titratable acidity is tartaric acid (Megazyme International Ireland, 2012).

The concentration of alcohol in wine can also be determined through titration (see method 5.7). It is important to measure the concentration of alcohol because; it must be expressed on the bottle label in industry, it determines how much wineries have to pay the government in fees and for quality control (Smith, Gould, Monteath, & Smith, 2009). If the concentration of alcohol is too high; generally over 10-15%, the yeast will die but some strains can withstand up to 21% ethanol (Smith, Monteath, Gould, & Smith, 2009). Also, once the ethanol production peaks briefly during fermentation, it will then decline progressively as ethanol begins to accumulate within the wine (Jacobs, 2007). Alcohol concentration can be measured using an Ebulliometer based on the fact that ethanol boils at 78.5°C and pure water boils at 100°C (Smith, Monteath, Gould, & Smith, 2009). The boiling point of the wine, which contains a lot of water, is determined by the Ebulliometer and the

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difference between that temperature and the water’s boiling point is calculated (Smith, Monteath, Gould, & Smith, 2009). The difference in boiling temperature is directly linked to the presence of ethanol in the wine if there is little sugar content because sugar would increase the boiling point (Smith, Monteath, Gould, & Smith, 2009). Alcohol content can also be measured by a vinometer but sugar may interfere with the technique it relies upon so it can only be used to calculate alcohol percentage in dry wines (Hammond & McGraw, 2007).

The sugar levels in the wine can be measured using a Refractometer or a hydrometer. A Refractometer measures how well light travels through the wine, which is called the refractive index (Hammond & McGraw, 2007). A sample of the wine is placed under the prism cover plate then, while the Refractometer is pointed towards a source of light, the eyepiece is peered through to show the scale, which displays the brix % (1°brix= 1g sugar per 100mL liquid) (Hammond & McGraw, 2007). Because sugar breaks down into ethanol during fermentation, the potential alcohol of the wine can be determined from the °Brix in the following equation: Potential alcohol (%v/v) = 0.6 x °Brix – 1 (Smith, Gould, Monteath, & Smith, 2009). Light is passed through the wine and the degree of light bending is dependent on the quantity of dissolved solids present (Smith, Gould, Monteath, &Smith, 2009). Because the main dissolved solid in wine is sugar, the higher the refractive index (read on the scale) the higher the sugar level (Smith, Gould, Monteath, & Smith, 2009). However, the refractive index is dependent on the temperature and most refractometers are calibrated to 20°C so if that is not the temperature, adjustments to the reading have to be made using a temperature compensation table, which should be a part of the refractometer’s instructions (Hammond & McGraw, 2007).

Hydrometers compare the weight of a liquid to the weight of water at 20°C (1g/mL) (Hammond & McGraw, 2007). This measurement is called specific gravity and it increases as the amount of dissolved solids increase, which, as previously mentioned, is mainly sugar in the case of wine (Smith, Gould, Monteath, & Smith, 2009). Thus, the specific gravity will drop as the wine undergoes fermentation because the sugar will break down. Specific gravity (SG) can be used to determine °Brix in the following equation: °Brix = 220 x (SG-1) + 1.6 (Smith, Gould, Monteath, & Smith, 2009).

Many factors influence the efficiency of fermentation, such as; temperature, pH, carbon dioxide and more (Smith, Gould, Monteath, & Smith, 2009). These factors also depend on the fruit and type of yeast used but generally white wine should undergo fermentation at 18-20 °C but it is possible to use a higher temperature if the wine maker wishes to establish more complex properties (Robinson & Jackson, 2011). Usually, red wine is fermented at higher temperatures up to 29 °C but if the temperature reaches much higher than that the flavours may “boil off” (Robinson & Jackson, 2011). Red wines can be fermented at lower temperatures, similar to the typical white wine temperature range, to bring out a stronger fruity flavour (Robinson & Jackson, 2011). The relationship between temperature and rate of fermentation are directly linked; so if the higher the temperature is, the faster the rate of fermentation will be and vice versa; if fermentation is occurring readily then the temperature will increase (Gladish, 1999). Therefore, the temperature must be monitored carefully as the ethanol fermentation can cause the wine to reach a temperature out of the optimum range and if the temperature exceeds 30°C, the yeast will either become inactive or die and thus the wine will be spoiled (Robinson & Jackson, 2011). Both pH and temperature can be measured with a multiparameter, but it also measures salinity, total dissolved solids and conductivity. In Australia, the legal limit of soluble chlorides in wine is 1g/L or about 1000ppm (Australian government, 2012).

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2.1.0 Control hypothesis:

It is expected that the alcohol concentration for the control wine will reach between 11.0-11.6% because of the mass of sugar that was added to the must. As seen in the equation for fermentation; per one mole of glucose two moles of ethanol are produced and because of this ratio, the alcohol concentration can be predicted. The must already contained about 78 grams of sugar per litre, which was determined from the specific gravity, and if no more sugar were to be added then the potential alcohol content would have been 3.9% but sugar was added to reach the desired ethanol percentage of 11.6%. Due to an error in initial calculations, 100 grams less of sugar was added than needed, which in 10L would only be 10g/L less. In the potential alcohol content table, the next increment down from 11.6% is 11.0% and 13g/L less sugar, therefore the expected potential alcohol is from 11.0-11.6%.

2.1.1 Variable hypothesis:

It is expected that the alcohol concentration for the variable wine will be lower than that of the control wine. This is because in high concentrations, oxygen can be toxic to yeast, which is required in the process of fermentation to produce ethanol. However, the yeast may still produce ethanol in the presence of oxygen if they are supported with good nutrition but it is likely that the ethanol production will be somewhat hindered by the oxygen present. Also, if there is more oxygen present then the yeast may undergo aerobic fermentation more often than usual, which does not produce ethanol.

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2.2.0 Aim:

To produce a fruit wine and conduct various analytical tests on it to compare it those made in industry. A variable is to be chosen and carried out on a small quantity of the wine, while the majority is left as the control to compare the difference in results that the variable caused.

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3.0 Risk Assessment:

Substance Risk Control Measure

Glassware Breakages and cuts Handle with care Dispose of broken glass

immediately and properly- using dustpan and brush, NOT fingers

Paring knife Sharp blade may cause cuts if used incorrectly.

May be used to stab another person, causing grievous injuries.

Keep knife sharp by means of sharpening stone using kerosene as lubricant. Blunt knives are more likely to cause injury due to the excessive force required to cut.

Store securely Always cut on or against

a wooden surface. Never cut on or against a hard surface, since this will blunt blade.

Carbon dioxide Harmless (in quantities generated during experiments)

Toxic at high concentrations in air due to absorption in blood, lowering the pH.

Magnesium burns in carbon dioxide to form magnesium oxide and carbon.

None required as it is armless in quantities generated during these experiments

Ethanol Highly flammable Slightly toxic; prolonged

contact with skin causes irritation

Forms violently explosive mixtures with nitric acid and other oxidising agents

Reaction of ethanol with acidified dichromate solution is highly exothermic

Reacts violently with potassium

Store and use away from ignition sources

Do not heat ethanol in a container over an open flame; use a water bath that is spark proof.

If a fuel is required, use metaldehyde or hexamine tablets

Only use as instructed; do not create mixtures

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sodium hypochlorite solution Toxic; evolves toxic chlorine gas

Skin irritant Corrosive

Wear gloves and safety goggles

sodium metabisulfite Moderately toxic; releases toxic sulphur dioxide, especially on contact with acids.

electric water bath Unless certified to be intrinsically safe, the electric components of a water bath are a possible ignition source

Check for electrical safety each time before use.

Test and tag at regular intervals

Do not use water bath with flammable liquids.

electronic balance Can be knocked off bench, with potential injury to feet

Danger of electrocution, especially in wet areas or if wiring is defective

Keep back from edge of bench

Keep clean and tidy; remove spilled chemicals immediately

Check wiring for damage each time before use

Test and tag at regular intervals

Electric vacuum pump Fumes can cause light-headedness

Fumes released from pump should be vented outside a window or into a fume cupboard; do not inhale fumes

Check for electrical safety (test and tag) at regular intervals, if used in laboratory or other hazardous environment.

Acetaldehyde solution Slightly toxic Do not ingest0.005M iodine water Lung-irritant vapour of

iodine evolved from the concentrated solution; toxic.

Use a fume cupboard or well-ventilated area

0.04M potassium dichromate solution

Slightly toxic Do not ingest

Potassium iodide Slightly toxic Do not ingest1M sodium hydroxide solution Corrosive to skin and

eyes; toxic. Do not ingest Wear gloves and safety

goggles0.1M sodium hydroxide solution Slightly toxic Do not ingest1M sodium hydroxide solution Moderately toxic Do not ingest0.1M sodium thiosulfate Moderately toxic; forms Do not ingest

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toxic gases on contact with acids and on heating

When using with acids or heat, use a fume cupboard or well-ventilated area

Sulphur dioxide gas Harmless in quantities generated during these experiments

Much higher concentrations can be highly toxic and irritating to lungs; may cause asthma attack

Extremely pungent odour

When using a higher concentration, use in fume cupboard or well-ventilated area

Sulphuric acid solution (0.5 M to 4 M)

Corrosive; strongly acidic Do not ingest Wear gloves and safety

gogglesSulphuric acid solution (4 M to 16 M)

Highly corrosive to skin and eyes; much heat evolved when mixing with water; evolves toxic fumes on heating

Always add acid to water slowly with vigorous stirring

Wear gloves and safety goggles

When using a higher concentration, use in fume cupboard or well-ventilated area

Phenolphthalein Harmless but has strong laxative qualities

Do not ingest

Pectinase Eye and skin irritant Wear gloves and safety goggles

Ascorbic acid 3% solution

Potassium metabisulfite 5% solution

Eye and skin irritant Wear gloves and safety goggles

Yeast

Refractometer Prolonged exposure to bright light can cause eye damage

Do not point at the sun

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4.0 Materials: Must making

Newspaper sheets (4-5) Bucket Chopping board Knives x2 Measuring jug Tea towel Elastic string Wooden stirring spoon Detergent Dilute domestos Fruit (6-7kg) Teaspoon Yeast nutrient

Acid blend Pectinase Ascorbic acid 3% solution Potassium metabisulphite 5% solution Funnel Tablespoon Sugar Yeast Glass cider bottle Balloon Scales Bowl

4.1 Materials: Into the Fermenter

Bucket Strainer Wooden stirring spoon Funnel Large demijohns x2 Cider bottles x2

Detergent Dilute domestos Newspaper sheets (4-5) Sheet of muslin Gas traps x4

4.2 Materials: Sugar calculations

Detergent Dilute domestos Thermometer Measuring cylinder Jug Calculator (optional)

4.3 Materials: Racking the wine

Detergent Dilute domestos Two demijohn bottles Plastic tube

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Newspaper Campden tablet x1 ½

4.4.0 Materials: Using a hydrometer

Detergent Dilute domestos 100mL measuring cylinder Funnel Hydrometer Newspaper

4.4.1 Materials: Using a refractometer

Detergent Dilute domestos Newspaper Refractometer kit Distilled water Paper towel Small sample of the wine

4.4.2 Materials: Using a multiparameter

Detergent Dilute domestos Newspaper Multiparameter 250mL beaker Wine sample (about 150mL)

4.4 Materials: Acid-base titration

Detergent Dilute domestos Newspaper 0.1M standardised NaOH solution Phenolphthalein indicator

250mL conical flasks x3 10.0mL pipette Burette Electric vacuum pump Clamp and stand

4.5 Materials: Assessing sulphur dioxide titration

Detergent Dilute domestos Newspaper 60mL control wine 40mL 1M sodium hydroxide solution

100mL standard iodine solution (approximately 0.005M)

30mL 2M sulphuric acid Starch indicator 250mL conical flasks x3

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20mL pipette Pipette filter 20mL measuring cylinder Burette

Clamp and stand Small funnel (optional) White tile

4.6 Materials: Concentration of alcohol titration

Detergent Dilute domestos Newspaper 10mL sample of control wine 60mL potassium dichromate solution

(0.04M) 100mL standard sodium thiosulphate

solution (0.1M) 30mL of 40% sulphuric acid 6g potassium iodide 250mL distilled water Starch indicator

10mL pipette 20mL pipettes x2 Pipette filter 250mL volumetric flask 250mL conical flasks with stoppers x3 10mL measuring cylinder Small funnel (optional) Burette Clamp and stand White tile Hot water bath

4.7 Materials: Aerating the variable wine

Aerating machine Muslin Elastic band

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5.0 Method: Must making

Hands were washed thoroughly with warm soapy water. Knives, chopping board, bucket, jug, wooden stirring spoon, glass cider bottle, a funnel and can opener were washed with warm water and detergent then sprayed with dilute domestos and rinsed. The working bench was covered in newspaper then the chopping equipment was placed on top. The strawberries were washed then hulled and chopped with the sterilised knives and placed in the bucket. The canned pineapple and lychees were opened and also placed in the bucket.

100mL of warm water was put into a jug with ½ teaspoon of yeast nutrient, ½ teaspoon of acid blend and ½ teaspoon of pectinase and swirled to combine then added to the bucket, which was then filled to the 10L mark with warm water. 10mL of ascorbic acid and 10mL of potassium metabisulphite was added to the bucket and stirred with a sterilised wooden spoon.

A funnel was placed in the opening of the glass cider bottle and 1 teaspoon of yeast, 2 tablespoons of sugar, 1 cup of warm water and ¼ teaspoon of yeast nutrient were poured in and carefully shaken well then left for about 20 minutes in a warm place until a frothy head developed. Two tablespoons of sugar were then added and the bottle was filled the rest of the way with warm water. A balloon was placed over the neck of the bottle to capture CO2 and a tea towel was placed over the top of the bucket and held in place with an elastic string and they were left in a warm place for 24 hours. The newspaper was thrown out, the equipment washed and the work bench wiped down.

The next day, calculations were done to determine the mass of sugar that needs to be added depending on the desired alcohol percentage of the wine (see method 5.2 and appendices 9.2). This was done with the use of a hydrometer, which can also be used throughout the winemaking process to monitor the sugar level that changes as a result of fermentation (see method 5.4). A wooden stirring spoon and a bowl were washed with warm water and detergent then sprayed with dilute domestos and rinsed. After the sugar calculations were done, the required mass of sugar was poured into the bowl, which was on a set of scales and it was then poured into the bucket as well as ¾ of the cider bottle (see appendices 9.8.0 and 9.8.1) contents then stirred with the wooden spoon. The tea towel and elastic string were replaced and the bucket was left in a warm place. The newspaper was discarded, all the equipment washed and the work area wiped down.

The next day, a wooden stirring spoon was washed with warm water and detergent then sprayed with dilute domestos and rinsed. The bucket’s contents were stirred thoroughly in attempt to assist the sugar in dissolving and to combine the flavours. The fruit was allowed to soak in the bucket for a few days.

5.1 Method: Into the Fermenter

Before straining the fruit, hands were washed thoroughly and a bucket, a strainer, a wooden stirring spoon, a funnel 2 large sealable bottles and 2 cider bottles were washed with warm water and detergent then sprayed with dilute domestos and rinsed. Newspaper was laid out on the floor and the bucket clean placed on it with the strainer on top. The contents of the original bucket were poured through the strainer in a few lots as the strainer had to be emptied of fruit when it became

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too full to pass the liquid through with ease. The fruit in the strainer was squished using pressure from clean hands to extract more juice and then emptied and the pouring continued until the original bucket was empty. The original bucket and the strainer were then rinsed and the strainer was placed on top of the bucket with a sheet of muslin in it which the liquid was then poured through. The empty bucket and the muslin were then rinsed and the strainer was placed on top of the empty bucket with the muslin in it and the liquid was poured through again.

The last ¼ of the starter bottle was poured into the bucket and stirred with the sterilised wooden spoon. 0.5mL/ L must of ascorbic acid and potassium metabisulphite were added (5mL each). The two demijohn bottles were then filled with the liquid by pouring it through the funnel and then the leftover was poured into two cider bottles. Gas traps were put on each bottle, which were then left in a warm place. The newspaper and muslin were discarded and the strainer and bucket were washed.

5.2 Method: Sugar calculations

A measuring cylinder, hydrometer, thermometer and a jug were washed with warm water and detergent then sprayed with dilute domestos and rinsed. Newspaper was laid out on work bench and sterilised equipment placed on top. A sample of the liquid from the bucket was drawn off with the jug, carefully to avoid chunks of fruit and the specific gravity was found (see method 5.4).

The temperature of the liquid was taken and a specific gravity correction table (see appendices 9.2.1) was used to slightly adjust the reading from the hydrometer as necessary (if it is not 20°). Using a potential alcohol content table (see appendices 9.2.2); the specific gravity reading closest to that on the hydrometer (with possible adjustments) was chosen and then the mass of sugar per litre it needed to contain was read. The desired alcohol content for the wine was chosen and it was seen how much sugar is needed to achieve that by looking in the adjacent column under ‘sugar per litre’. The mass of sugar already acquired was subtracted from the mass of sugar in the desired alcohol to find the amount of sugar that needed to be added per litre then this was multiplied by the volume of wine (in litres) that is being made.

5.3 Method: Racking the wine

Two demijohn bottles (the same sizes as the ones currently in use) and a plastic tube were washed with warm water and detergent then sprayed with dilute domestos and rinsed. Newspaper was laid on the floor and the empty demijohn was put on top. One end of the tube was put into one of the full demijohns (which was on the table so gravity would assist the process) about ¾ of the way down, careful to not make contact with the lees in the bottom. The other end of the tube was sucked until the liquid started flowing through the tube and when it was nearly at the other end it was put into the mouth of the sterilised demijohn. The tube was held there until most of the liquid had been transferred; just leaving the lees behind and then the tube was quickly removed from the initial demijohn. The same was done with the other demijohn and then one full Campden tablet was crushed and put into the control wine and half of a Campden tablet was crushed and put into the variable wine (the smaller demijohn). The gas traps were replaced.

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5.4.0 Method: Qualitative tests- hydrometer

A 100mL measuring cylinder, a funnel and the hydrometer were washed with warm water and detergent then sprayed with dilute domestos and rinsed. On top of laid out newspaper, the measuring cylinder was filled about ¾ of the way, using the funnel. The hydrometer was placed in the cylinder and pushed down to coat some of the stem, and then the rest of the cylinder was filled with the juice. The hydrometer was spun to rid any gas bubbles that may have been attached, and the marking was read at eye level (see appendices 9.1) when it had stopped spinning.

5.4.1 Method: Qualitative tests- refractometer

The refractometer was first calibrated by placing a few drops of distilled water on the daylight plate and then prism cover plate was placed down, ensuring there were no gas bubbles in the liquid. The scale which displayed the °Brix was read when peering through the eyepiece towards a light source (not directly at the sun) and the contrast line should be exactly on the “0” mark. If it’s not, then the screw driver that comes with the refractometer can be used to twist the calibration screw until the line is exactly on zero. If the scale seems unclear then adjustments can be made by twisting the focus mechanism around the eyepiece. The water was then wiped away gently with paper towel and a few drops of the wine were put onto the daylight plate of the refractometer and the reading process was repeated. The same was done with the other wine after the daylight plate had been rinsed with water and it was rinsed again before being put away.

5. 4.2 Method: Qualitative tests- multiparameter

A 250mL beaker was washed with warm water and detergent then sprayed with dilute domestos and rinsed and the sensor tip of a multiparameter was washed thoroughly with warm water (after the cap was removed). On top of laid out newspaper, the beaker was filled about half way with the control wine and the multiparameter was turned on and sat into the liquid with the sensor tip immersed. The screen displayed the temperature and the first reading; either salinity, total dissolved solids, conductivity or pH and they were recorded. The mode button was pressed to show the next reading until all of them were recorded. The tip was rinsed off before replacing the cap and putting away (see appendices 9.6.0 and 9.6.1 for labelled diagrams).

5.5 Method: Acid-base titration

All equipment was washed with warm water and detergent then sprayed with dilute domestos and rinsed. On top of laid out newspaper, about 100mL of the control wine was poured into a Buchner flask and a rubber stopper was fitted securely in the top and the side arm was connected to a vacuum pump. The flask was shaken gently for about 2-3 minutes under vacuum. The burette was filled with 0.1M sodium hydroxide (NaOH). About 100mL of distilled water was added to a 250mL conical flask and 3-4 drops of phenolphthalein indicator was added a mixed well. Sodium hydroxide solution was added from the burette until the solution reached the equivalence point in which it turned a pale pink colour that persisted for at least 30 seconds. Then 10.0mL of the degassed wine

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was added into the conical flask using a pipette. For ease, the burette was filled to the top mark with the 0.1M sodium hydroxide and the initial burette reading was recorded. The solution in the flask was titrated with the NaOH from the burette until the pale pink colour persisted for at least 30 seconds. The final burette reading was read and the difference between it and the initial reading was calculated, which gave the titre value. Three lots of this titration were done, using 10.0mL from the same degassed wine in the Buchner flask each time and the average of the results was calculated. This number was put into the calculations as the titre value to discover the mass of tartaric acid in one litre of wine (see appendices 9.5.0).

5.6 Method: Assessing sulphur dioxide titration

All equipment was washed with warm water and detergent then sprayed with dilute domestos and rinsed. On top of laid out newspaper, 20.0mL of wine was transferred to each of three 250mL conical flasks using a pipette. To each flask about 12mL of 1M sodium hydroxide solution was added and the flasks were allowed to stand for 15 minutes to release sulphur dioxide bound in complex compounds. A burette was filled with standard iodine solution and the initial burette reading and concentration of the solution was recorded. To one flask, about 10mL of 2M sulphuric acid and 1-2mL of starch indicator was added and the mixture was immediately titrated with iodine solution. When the equivalence point was reached in which a blue colour persisted for at least 30 seconds, the burette reading was recorded. The method was repeated for the two other flasks and the burette was refilled with standard iodine solution before each. From the three results the average was calculated and put into the calculations to discover the total mass of sulphur dioxide as the titre value (see appendices 9.5.1).

5.7 Method: Concentration of alcohol titration

All equipment was washed with warm water and detergent then sprayed with dilute domestos and rinsed. On top of laid out newspaper, 10mL of the control wine was put into a 250mL volumetric flask using a pipette and the volume was made up to the 250mL mark with distilled water and mixed thoroughly. From this diluted wine, a 20mL aliquot was put in each of three conical flasks. To each flask, a 20mL aliquot of 0.04M potassium dichromate solution was added. 10mL of 40% sulphuric acid was added to each flask using a measuring cylinder and a rubber stopper was inserted loosely into the tops of each and they were then heated in a water bath at about 45-50°C for 10 minutes. After 10 minutes, they were removed from the water bath and 2g of potassium iodide was added to each. A burette was filled with standard thiosulphate solution and titrated against the contents of one flask and when the initially brown solution formed a green colour 1-2mL of starch solution was added, which turned it blue. More thiosulphate solution was added to the flask from the burette until the equivalence point was reached in which the colour changes from blue to a clear green colour. The final burette reading was recorded and then the other two flasks were titrated using the same method and the burette was refilled before both. From the three results the average was calculated and put into the calculations to discover the concentration of alcohol as the titre value (see appendices 9.5.2).

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5.8 Method: Aerating the variable wine

A tube that was attached to an aerating machine (see appendices 9.7.0) was rinsed and put into the variable wine. The machine was turned on for about a minute to introduce oxygen into the wine. This was done every possible day after all the qualitative tests were done so the added oxygen and bubbles didn’t have an effect. Instead of inserting a gas trap, a sheet of muslin was tied over the neck of the bottle with an elastic band to keep bugs out but allow the entry of oxygen (see appendices 9.7.1).

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6.0 Results:

6.1 Figure 1- Control wine resultsDays since initiation

Temperature (°C)

pH Conductivity (ppb)

TDS (ppm)

Salinity(ppb)

Hydrometer Refractometer (%)

Ebulliometer (°C/ %)

Day 2 - - - - - 1.032 - -Day 9 - 3.42 1273 0.906 630 - - -Day 10 - - - - - 1.010 - -Day 15 18.1 3.52 1380 0.981 755 0.990 5.5 -Day 18 19.4 3.75 1391 0.985 962 0.988 6.5 -Day 22 17.8 3.60 1430 1.02 710 0.988 6.2 -Day 23 18.2 3.60 1422 1.01 706 0.992 5.8 Trial 1: 90.2/

14.0Trial 2: 90.4/ 14.0

Day 25 17.7 3.68 1434 1.02 708 0.998 7.0 -Day 29 20.6 3.75 1479 1.04 811 0.988 7.0 -Day 32 19.6 3.67 1509 1.07 751 0.990 6.2 90.8/ 13.7Day 36 19.7 3.65 1557 1.11 779 0.991 6.2 -Day 38 16.7 3.72 1531 1.09 761 0.992 6.7 90.7/ 13.7Day 39 18.2 3.69 1589 1.13 794 0.990 7.0 -

Days since initiation

Temperature (°C)

pH Conductivity (ppb)

TDS (ppm)

Salinity(ppb)

Hydrometer Refractometer (%)

Ebulliometer (°C/ %)

Day 10 18.2 3.48 1376 0.977 682 1.012 - -Day 15 18.5 3.44 1409 0.999 771 0.990 7.0 -Day 18 19.5 3.80 1406 0.992 764 0.989 4.0 -Day 22 19.4 3.75 1455 1.03 721 0.990 6.8 -Day 23 18.0 3.74 1436 1.02 786 0.992 7.0 -Day 24 - - - - - - - 90.7/ 13.1Day 25 17.9 3.66 1468 1.05 729 0.989 5.6 -Day 29 20.1 3.90 1597 1.11 873 0.990 6.8 -Day 32 19.3 3.71 1592 1.13 797 0.992 6.6 91.1/ 13.1Day 36 20.1 3.65 1612 1.14 809 0.990 6.4 -Day 38 17.0 3.74 1615 1.15 805 0.992 6.6 90.9/ 13.3Day 39 18.2 3.70 1676 1.19 834 0.990 6.7 -

6.2 Results: Figure 2- Variable wine results

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The table above displays the results from the qualitative tests that were performed on the control wine throughout the entire winemaking process. Note: The first number in the ebulliometer column is the boiling point for the wine and the second number is the percentage of alcohol it contains based on the difference between the boiling point of the water and the wine, which can be determined using a conversion wheel (appendices 9.9.2).

6.3.0 Figure 3- Hydrometer for control wine

6.4.0 Figure 5: Control wine Brix vs. Ebulliometer

6.4.1 Figure 6: Variable wine Brix vs. Ebulliometer

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1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 390.96

0.97

0.98

0.99

1

1.01

1.02

1.03

1.04R² = 0.914047847154468R² = 0.890933470992855

Hydrometer readings

ControlPolynomial (Control)VariablePolynomial (Variable)

Day since initiation

Spec

ific g

ravi

ty (S

G)

22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 390

2

4

6

8

10

12

14

16

R² = 0.685108165254735

R² = 1

Relation of °Brix to alcohol %

°BrixPolynomial (°Brix)% alcoholPolynomial (% alcohol)

Days since initation

°Brix

/ %

alco

hol

The graph above shows the relation of °Brix to alcohol percentage in the control wine over a period of time. It can be seen that the refractive index (measured in °Brix) is inversely related to the alcohol percentage so when the °Brix decreases the alcohol percentage increases.

The graph above shows the specific gravity from the hydrometer for the control wine versus the variable wine from day 1 to day 39 of the fermenting process.

6.5.0 Figure 7: Salinity in control wine vs. variable wine

9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 390

200

400

600

800

1000

1200

R² = 0.426946199430182R² = 0.584818826734903

Salinity (control vs. variable wine)

ControlPolynomial (Control)VariablePolynomial (Variable)

Days since initiation

Salin

ity (p

pm)

23

22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 390

2

4

6

8

10

12

14

R² = 0.476118792963272

R² = 1

Relation of °Brix to alcohol %

°BrixPolynomial (°Brix)% alcohol

Days since initiation

°Brix

/ %

alco

hol

The graph above shows the salinity for the variable and control wines from day 9 to day 39 of the fermenting process, during which the variable wine was being aerated. The salinity never reached over 1000ppm, so both wines are within the legal limit.

6.6.0 Figure 8: pH in control wine vs. variable wine

9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 393.1

3.2

3.3

3.4

3.5

3.6

3.7

3.8

3.9

4

R² = 0.662686694305097

R² = 0.581310405265197

pH values (Control vs. variable wine)

ControlPolynomial (Control)VariablePolynomial (Variable)

Days since initiation

pH v

alue

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The graph above shows the pH values for the variable and control wines from day 9 to day 39 of the fermenting process, during which the variable wine was being aerated.

6.7 Figure 9: Ebulliometer results

1 4 7 10 13 16 19 22 25 28 31 34 3712.6

12.8

13

13.2

13.4

13.6

13.8

14

14.2R² = 1R² = 1

Control vs. variable percentage alcohol

ControlPolynomial (Control)VariablePolynomial (Variable)

Days since initiation

Alco

hol p

erce

ntag

e

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The graph above shows the alcohol percentages, which were calculated from an ebulliometer, for the variable and control wines.

7.0 Discussion:

The hydrometer was not read properly every time it was used so some of the readings were recorded wrong, which caused the results to appear very out-of-pattern so a definite trend could not be concluded. Some of the readings were recorded much too high so the potential alcohol level would have been expected to be much higher than it was in reality but the mistakes were found and adjustments to the results were made to what the readings actually were. There is a possibility of the adjusted readings not being 100% accurate and that would affect the display of the results but not as severely as the initial mistakes.

The refractometer and multiparameter weren’t always calibrated before usage so the results obtained from those tests may be slightly affected because if they weren’t reset to neutral beforehand then some residue from a previous test may alter the results and thus the relationships between different results may be seen differently. Also, the °Brix from the refractometer weren’t adjusted according to the temperature even though the result is based off the assumption that the temperature was 20°C. The refractive index is temperature-dependant so the results that were obtained would have been slightly different because the temperature wasn’t accounted for but not by a substantial amount.

After each time the wines were racked, potassium metabisulphite was added to both the control and variable wines. Potassium metabisulphite provides the wine with a source of sulphur dioxide, which serves the purpose to not only stop unwanted microbes from growing but also to prevent oxidation. The purpose of the variable wine was to introduce oxygen to determine the effect oxidation has on wine compared to the control but the oxidation would have been hindered by the added sulphur dioxide so the difference would be less dramatic than planned. Next time, the potassium metabisulphite should only be added to the control wine and another form of antimicrobial agent added that doesn’t also prevent oxidation.

As seen in figures 3 and 4, as fermentation occurred the specific gravity dropped because the sugar was being broken down to produce alcohol so the density of the water decreased. Towards the end of the time period, the trend began to ease off because the alcohol percentage was reaching its peak. The difference between the control and variable hydrometer readings aren’t significantly different because the introduction of oxygen didn’t affect the amount of sugar in the wine but caused the percentage of alcohol to be lower due to the oxygen inhibiting the yeast from producing ethanol from the glucose. Because oxygen was more abundant in the variable wine, aerobic respiration, which doesn’t produce ethanol, may have taken place more than in the control wine and thus a lower alcohol percentage was produced.

It can be vaguely seen in figures 5 and 6, that the refractive index (measured in °Brix) is inversely related to the alcohol percentage so when the °Brix decreases the alcohol percentage increases. This is because the main dissolved solid in wine is sugar so the higher the refractive index the higher the sugar level and glucose (a type of sugar) produces alcohol in fermentation. So the glucose breaks down to produce ethanol, which makes the °Brix drop and simultaneously the alcohol percentage increases.

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In figure 9, it can be seen that the percentage of alcohol for the variable wine was lower than that of the control. This may be because in high concentrations, oxygen can be toxic to yeast and yeast is required in the process of fermentation to produce ethanol. Though the yeast was still producing alcohol, it was slightly hindered by the oxygen present. Also, the extra oxygen present may have caused the yeast to undergo aerobic fermentation more often than usual, which does not produce ethanol. Whereas in the control wine; the lack of oxygen would have resulted in more anaerobic respiration and thus more ethanol.

Figure 8 shows that the pH values for both wines weren’t dramatically different but for the majority of the time, the variable wine’s pH was higher than the control’s. That is likely to be because the ethanol concentration in the variable wine was lower than that in the control so it was less acidic.

The titratable acidity should ideally be between 6.5-8.5g but through a titration and calculations, it was determined that the control wine contained 6.22g/L. The legal limit for total sulphur dioxide concentration is 250mg/L in a dry wine (<35g/L sugar) and 300mg/L in a sweet wine (>35g/L sugar) and the control wine had a calculated 0.91g/L. The salinity never reached over 1000ppm, so both wines are within the legal limit.

It was expected that the alcohol concentration for the control wine would reach between 11.0-11.6% because of the mass of sugar that was added to the must. The wine actually reached 14.0% at one point but then decreased to 13.7%, which is still more than expected. This may have occurred because the initial sugar content, measured by the hydrometer, was higher than measured, which would cause more ethanol to be produced than expected. The sample of must that was taken to read the hydrometer in was scooped off the top of the must bucket so there may have been a higher concentration of sugar at the bottom. It was expected that the alcohol concentration for the variable wine would be lower than that of the control wine because the oxygen would inhibit the fermentation process and this was correct.

In future investigations; the mass of water produced should be measured to determine how much more aerobic fermentation is occurring in the oxidated wine compared to the control wine because water only results in aerobic respiration of yeast and not anaerobic. This would then justify the lower alcohol percentage in the variable wine.

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8.0 Conclusion:

A fruit wine, made from strawberries, pineapple and lychees was made and various analytical tests were conducted upon it to compare it those made in industry. The titratable acidity was just below the ideal range for wine, the total mass of sulphur dioxide was over the legal limit and the salinity for both wines was below the legal maximum. Oxidation was chosen as a variable and carried out on a small quantity of the wine, while the majority was left as the control to compare the difference in results that the variable caused. The results weren’t substantially different, which is believed to be because potassium metabisulphite was added to the variable wine, which helps to prevent oxidation from occurring. The final alcohol concentration recorded for the variable wine was 13.3% and the control wine was 13.7% so there was a difference of 0.4% alcohol. Oxidation didn’t quantifiably affect the specific gravity because the level of sugar in the wine can’t be altered by oxygen but oxygen can combine with glucose in aerobic respiration in which ethanol is not produced. Slight differences between the two wines were noticed in the pH values because the higher concentration of ethanol caused the control wine to have a lower pH throughout the majority of the process.

It was expected that the alcohol concentration for the control wine would reach between 11.0-11.6% because of the mass of sugar that was added to the must. The wine actually reached 14.0% at one point but then decreased to 13.7%, which is still more than expected. This was concluded to be because the sugar content, read off the hydrometer, may have been higher than measured because the sample was taken from the surface of the must when the sugar content could have been greater at the bottom, thus causing more ethanol to be produced than expected. It was expected that the alcohol concentration for the variable wine would be lower than that of the control wine because the oxygen would inhibit the fermentation process and this was correct.

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9.0 Appendices:

9.1 Reading a hydrometer:

Picture source: http://www.avogadro-lab-supply.com/content.php?content_id=2

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This picture gives an example of a specific gravity reading off a hydrometer, which should be read at the bottle of the meniscus and at eye level.

9.2 Sugar calculations:

9.2.1 Specific gravity correction table:

Picture source: (Hammond & McGraw, 2007)

9.2.2 Potential alcohol content table:

Picture source: (Hammond & McGraw, 2007)

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The above photo shows a table that is used during calculating the mass of sugar required to reach the desired potential alcohol content. Once the specific gravity is read off the hydrometer and necessary changes are made using table 8.2.1, the current potential alcohol content can be found in column 3 and the current mass of sugar per litre (in grams) can be seen in column 2 all in the same row.

The above photo shows a table that gives the required adjustments for the specific gravity reading based on the temperature of the liquid.

9.2.3 Our sugar calculations:

9.2.4 Continued sugar calculations:

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The above photo shows the first half of the calculations required to determine the mass of sugar that needed to be added to the must on day 2 to start the fermentation process.

The above photo shows the second half of the calculations required to determine the mass of sugar that needed to be added to the must on day 2 to start the fermentation process.

9.3.0 Calibrating refractometer scale:

Pictures’ source: http://www.grapestompers.com/refractometer_use.aspx

9.3.1 Refractometer scale example:

Pictures’ source: http://www.grapestompers.com/refractometer_use.aspx

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The picture above shows the scale in a refractometer, displaying °Brix, while it’s being calibrated with pure water.

The picture above shows an example of a scale in a refractometer, displaying °Brix, while a few drops of an unknown liquid is placed on the prism.

9.3.3 Labelled refractometer diagram:

Picture source: http://www.intercononline.com/jokisch/RHB-32-refractometer.htm

9.4 Free sulphur dioxide quantities:

Picture source: (Smith, Monteath, Gould, & Smith, 2009)

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The photo above shows a table that suggests a guideline for the quantity of free sulphur dioxide that should be contained in white wine dependant on its pH.

The picture above shows a labeled refractometer diagram; including all parts referred to in method 4.4.1.

9.5.0 Titration calculations- Total mass of sulphur dioxide:

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The photo above shows the calculations of the mass of sulphur dioxide in the control wine. These calculations used the average titre value from the titration (see method 5.6).

9.5.1 Titration calculations- Titratable acid:

35

The photo above shows the calculations of the total acidity in the control wine, assuming that all the acid is tartaric. These calculations used the average titre value from the titration (see method 5.5).

9.5.2 Titration calculations- Concentration of alcohol:

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The photos above shows the calculations of alcohol concentration in the control wine. These calculations used the average titre value from the titration (see method 5.7).

Sensor tip

Mode buttonOn/ off button

Temperature reading

Other qualitative readings

9.6.0 Labelled multiparameter:

Photo source: http://www.industrysearch.com.au/Multi-Parameter-Pocket-Tester-PCSTestr-35/p/93204

9.6.1 Our multiparameter:

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Sample of wine

The above photo shows a labeled multiparameter to assist with method 4.4.2.

The above photo shows a multiparameter from one of our control wine tests.

9.7.0 Aerating the variable wine- aerating machine

9.7.1 Aerating the variable wine- muslin lid

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The above photo shows the aerating machine used to introduce oxygen into the variable wine.

The above photo shows the muslin that was tied around the neck of the variable wine to allow oxygen entry, instead of using a gas trap.

9.8.0 Adding sugar to the must:

9.8.1 Adding starter bottle to the must:

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The above photo shows the starter bottle being added to the must.

The above photo shows the sugar being added to the must after the calculations were done.

9.9.0 Industrial gas trap:

9.9.1 Balloon gas trap:

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The above photo shows balloons that were used to stop the entrance of oxygen but capture carbon dioxide that the yeast produced during fermentation.

The above photo shows a gas trap that was used to stop the entrance of oxygen but capture carbon dioxide that the yeast produced during fermentation.

9.9.2 Degrees to alcohol percentage conversion wheel:

Picture source: http://www.dwinesupplies.com/dws/itemDetails.asp?sn=&pid=2228

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The above photo shows a wheel that converts the difference in boiling points of the wine and water to the alcohol percentage when spun correctly.

10.0 Bibliography

Australian government. (2012, October 11). Wine Production Requirements. Retrieved August 24, 2013, from Australian Government ComLaw: http://www.comlaw.gov.au/Details/F2012C00776

Deeds, S. (2013, March 13). Yeast Propogation with Aerobic Respiration. Retrieved August 19, 2013, from Woodland Brewing Company: http://woodlandbrew.blogspot.com.au/2013/03/yeast-propogation-with-aerobic.html

Dharmadhikari, M. (2010). Wine Aeration and Its Adverse Effects. Retrieved August 2, 2013, from Iowa state university extension and outreach: http://www.extension.iastate.edu/wine/aeration

Gladish, S. (1999). Take Control of Must Temperature--And Reap the Benefits. Retrieved August 22, 2013, from WineMaker: http://www.winemakermag.com/stories/techniques/article/indices/19-fermentation/653-take-control-of-must-temperature-and-reap-the-benefits

Hammond, M., & McGraw, J. (2007). Fruit Wine EEI Resources. 1-2.

Jacobs, J. (2007, September 4). Ethanol fermentation. Retrieved August 20, 2013, from Wikipedia: http://en.wikipedia.org/wiki/Ethanol_fermentation

James A Kennedy, M. A. (2002). Effect of Maturity and Vine Water Status on Grape Skin and Wine Flavonoids. Retrieved July 10, 2013, from American journal of enology and viticulture: http://www.ajevonline.org/content/53/4/268.abstract

Kearney, C., & Bogolawski, M. (n.d.). Winemaking and the importance of pH testing. Retrieved August 20, 2013, from HANNA Instruments: http://www.hannainst.com/usa/whitepaper/Winemaking%20and%20pH.pdf

Megazyme International Ireland. (2012). TARTARIC ACID. Retrieved August 23, 2013, from Megazyme: http://secure.megazyme.com/files/BOOKLET/K-TART_1209_DATA.pdf

Plant, C. (2001). The Use of Sulphur Dioxide (SO2) in winemaking. Retrieved July 12, 2013, from BCAWA: http://www.bcawa.ca/winemaking/so2use.htm

Ribereau-Gyon, P. (2000). Handbook of Enology: Vol 2: The Chemistry of Winemaking.

Robinson, J., & Jackson, S. (2011, March 4). Fermentation in winemaking. Retrieved August 23, 2013, from Wikipedia: http://en.wikipedia.org/wiki/Fermentation_in_winemaking#cite_note-Oxford_pg_268-9

Smith, D., Gould, M., Monteath, S., & Smith, R. (2009). Chemistry in Use, teacher guide. Sydney: McGraw-Hill Australia.

Smith, D., Monteath, S., Gould, M., & Smith, R. (2009). Chemistry in Use BOOK 2. Sydney: McGraw-Hill Australia.

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Zoecklein, B. (2003, March 5). Series of notes on sulfur-containing compounds in wine. Retrieved August 20, 2013, from Enology notes: http://nanaimowinemakers.org/Steps/H2S_Issues.htm

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