Group 4 Internal Assessment
Partners: Bhavya and Katherine Research question: Does the concentration (mol dm3) of sulphur dioxide in wine rise or fall when exposed to air for different time periods (0, 75,150,225, 300 minutes)? Purpose:
Many adults enjoy the consumption of wine but are not aware of the different preservatives and chemicals that are added to the drink. Sulphur Dioxide, which is added to many food products including wine because it acts as a reductant, is ‘well known as a poisonous and allergenic substance (Eco-consult, n.d), making it a somewhat harmful ingredient. The purpose of this experiment is to determine how the amount of sulphur dioxide in white wine is affected by the exposure to the air over different time periods and whether this will negatively or positively affect the human body.
The boiling point of sulphur dioxide is -10˚C, therefore when it is above this temperature it is expected to evaporate. According to Rutherglen Estates, an Australian wine company,(Rutherglen Estates, 2011), the concentration of sulphur dioxide in wine reduces when subjected to aeration, this loss of sulphur dioxide increases over time. This reduction in sulphur dioxide can be beneficial for people with allergies but can be harmful for the wine as oxidation causes a loss of the fruity flavour, browning, and the development of aldehydic or nutty flavours (Dharmadhikari, 2013).
As the wine is left out for longer the sulphur dioxide content falls.
The amount of Sulphur dioxide
Amount of time
The equipment used
The rinsing techniques
The measurements of each
Sodium hydroxide (12ml)
White wine (20ml)
Sulphuric acid (10ml)
Starch indicator (2 ml)
+/- 0.5 seconds
+/- 0.06 ml
10ml measuring cylinder
25ml measuring cylinder
400ml White Wine
240ml of 1M sodium hydroxide
200ml of 2M sulphuric acid
300ml of 0.005M iodine solution
40ml starch indicator
Experimental Set up:
There were many steps undertaken to manage the variables within the experiment. The same person used the timers to make sure that the independent variable, the amount of time, was managed efficiently and accurately. There were also many steps taken to manage the controlled variables. The equipment used was controlled by using the same equipment during the entire experiment and the rinsing technique was controlled as it was completed by the same person and numerous rinsing’s were done to make sure that there was no leftover residue from previous experiments. Finally, the measurement of each substance was managed as the same equipment and person was used to measure out each substance for each titration.
1. Rinse all equipment with water, then distilled water, then the solution which will be in the piece of equipment. 2. Pour 80 ml of wine into a beaker.
3. Repeat step 2 for 5 beakers labelling them and leave them each for 0h, 1h and 15 minutes, 2h and 15 minutes, 3h and 15 minutes, 4h and 15 minutes respectively. 4. Fill burette with standard iodine solution. Record initial burette reading. 5. Pipette 20ml of wine into 4 separate conical flasks.
6. Add 12ml of 1M sodium hydroxide solution to each flask.
7. Leave for another 15 minutes.
8. Add 2ml of starch indicator, and 10ml of 2M sulphuric acid to each flask. 9. Titrate each flask with the iodine solution.
10. Stop when the solution turns a blue indigo colour and record final burette reading. 11. Repeat steps 4 to 10 at appropriate time.
12. Record findings.
Initial Volume (cm3) +/- 0.02 cm3
Final Volume (cm3) +/- 0.02 cm3
Titre(cm3) +/- 0.1cm3
Average titre (cm3)+/-0.04cm3
Bibliography: Dharmadhikari, M 2013 Wine Aeration and Its Adverse Effects, Iowa State University, accessed 25 November 2013, .
Shanahan, C 2011 Is aerating wine just hot air?, Rutherglen Estates, accessed25 November 2013, .
The use of Sulphur Dioxide in Must and Wine n.d., Eco-consult, Pdf, accessed25 November 2013, .
Xavier, L n.d. Titration, UCDAVIS, accessed 25 November 2013, .
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