It is up to the teacher and student to see if they are practical for their school situation. Any task documents from schools are not exemplars ; they are merely tasks that have been successfully used in assessment in Queensland schools but may have since been modified. The quality of Queensland wines is now recognised ajax antibacterial dish soap msds amongst the best in Australia. Overseas exports are increasing, particularly to international markets seeking premium quality boutique wines.
The Queensland wine industry has grown significantly over the years to cover a total of hectares. The majority of this growth has occurred during the past 20 years with significant plantings throughout the southeast corner of the State.
However, ajax antibacterial dish soap msds, winemaking is still somewhat of an art but ajax antibacterial dish soap msds strongly informed by science. Thus an interesting EEI can be undertaken in this context. After crushing the grapes the next step in the making of wine is the fermentation of the grape juice and pulp with various yeasts and bacteria.
Fermentation is an exothermic reaction so heat is generated during the process. To control the heat, the winemaker must choose a suitable vessel size or else use a cooling device.
In the case of an EEI, you might control the temperature by use of a water bath or a refrigerator. Fermentation at higher temperatures may have adverse effect on the woodworking and shed plans in stunning the yeast to inactivity and even "boiling off" some of the flavors of the wines.
How temperature and the final concentration of alcohol are related would make an ideal EEI. This is not such an important one and the effects may be small - but nevertheless important. You could repeat it with acidity as the independent variable and controlling the amount of sugar, ajax antibacterial dish soap msds, yeast, temperature and so on. As the alcohol concentration rises the yeast cell membranes become susceptible to rupture by the ethanol. Some yeasts are more susceptible than others.
Or you could look at the susceptibility of yeasts to [SO 2 ] - winemakers use SO 2 in the form of sodium metabisulfite to kill off wild yeasts as these are less tolerant than wine yeast to the SO 2. Sulfur dioxide is widely used in winemaking because of its antioxidant and antibacterial properties. You could hypothesise and test how SO 2 affects the performance of yeast.
Two ajax antibacterial dish soap msds methods for ajax antibacterial dish soap msds SO 2 in wine are included in the "sulfite" section later. Any fruit or juice works just fine although some require more sugar to be added. Also, my winemaking unit for chemistry teachers is available online. It is worth stressing here that you should not taste the wine being produced; this is not because of the alcohol but anorexia weight loss slowly rapidly because of the unsanitary conditions under which your wine is being made in a lab, not the Home Economics kitchen.
If ajax antibacterial dish soap msds intend tasting your wine then your risk assessment should state and evaluate that. The most common method is by redox titration. In this analysis, you add an excess of standardized acidified potassium dichromate solution to the wine which converts the ethanol to ethanoic acetic acid.
The amount of unreacted dichromate is then determined by adding an excess of potassium iodide solution which is also oxidised by the potassium dichromate to form iodine. The iodine is then back-titrated with a standard solution of sodium thiosulfate and a starch indicator.
The titration results are used to calculate the ethanol content of the original solution, ajax antibacterial dish soap msds. It is complex but works well and is very impressive. You have a problem if you are dealing with red wine as the red pigments mask the colour changes. In that case you have to extract the ethanol from the wine in effect, by various forms of distillation and carry on, as above, from there. Canterbury University NZ has quite a simple method for red wine: Chemistry teacher Emma Hodginkson from Mountain Creek State High has performed the Canterbury ethanol titration with her Year 12s for a few years and has found it very successful.
As it is a redox titration she says it works better in Ajax antibacterial dish soap msds 12 when the students have completed some redox theory whereas Year 11s find the calculations a bit heavy going. To overcome the practical difficulty in locating a small container to suspend above the dichromate - they use a plastic water bottle lid torous and cancer with cotton thread.
Some parafilm is used to seal the boiling tube, or a suitably sized stopper if possible. A pair of forceps is used to remove the dichromate tube without spilling into ajax antibacterial dish soap msds wine sample, the outside rinsed with water, and then titrated.
One caution in all of this: Manipulation of variables gives students a better chance of demonstrating all aspects of the assessment criteria. Alcohol content by distillation 2. Alcohol content by Ebulliometry 3. Alcohol content by boiling 4. Alcohol concentration by dichromate oxidation and titration 5. Alcohol concentration by Vinometer 6. Alcohol concentration Western Australia - Chemistry in Context. Many are just different strains of the same yeast but grow differently.
A good research question might be: There is a problem however, ajax antibacterial dish soap msds. For example, temperature, pH, sugar concentration, amount mass of yeast, surface area and so on. But when you are comparing two different categories of a variable, ajax antibacterial dish soap msds, such as type of yeast wine yeast vs. The choice of the categorical variables is not as common as using a continuous variable in Senior Chemistry EEIs, partly because categorical variables have their peculiar difficulties and this makes the design of this EEI far more complex than it looks at first glance.
It is not just a matter of comparing equal amounts of the two yeast products on the amount of alcohol produced. Do the yeasts each have an optimum pH and if so what pH will be chosen for the grape juice and why?
Is surface area a concern maybe if one is a bottom fermenter, and another a top fermenting yeast. Will a low sugar or high sugar juice be used - important as it may be the alcohol itself that inhibits the yeast.
And what about the dependent variable alcohol concentration: Some yeasts are slow eg the CY Slow White yeast from France takes its time but gets there in the end; it would be a brave decision to cut it off after 7 days. Lastly, some yeasts convert malic acid to alcohol as well as converting the sugar. Imagine using a yeast such as the Lalvin C from France which partially degrades malic acid. Another terrific idea for a wine EEI. The two common fruit sugars used in winemaking are glucose and fructose.
Grape juice is made up of these in roughly equal quantities. Another sugar used in the fermentation industry is sucrose cane sugar. Sucrose is frequently used as a cheap carbohydrate by breweries, wineries and other fermentation-based industries employing yeast.
It is a di-saccharide composed of D-glucose and D-fructose linked by an alpha-1,4 glycoside bond. In the initial stages of fermentation, sucrose is rapidly hydrolyzed into glucose and fructose by the action of the enzyme invertase on this bond. Then the sugars are transported across the cell membrane where they ferment and form alcohol. So investigating the fermentation of sucrose is really also about studying the fermentation of a mixture of glucose and fructose. This suggests a terrific EEI: As fermentation proceeds the ratio of fructose to glucose increases.
Therefore, fermented grape juice will contain more fructose than glucose as residual sugar. Fructose is the sweetest hexose sugar, approximately twice as sweet as glucose, and thus the wine gets an undesirable fructose sweetness, unbalanced by the sweetness of glucose.
So here is the starting point if you are doing an EEI. Pose the Research Question: One delicious complication though is that when glucose and fructose are mixed as in the case of fermenting sucrose; ajax antibacterial dish soap msds in an artificial mixture the glucose ferments faster than fructose.
Glucose seems to inhibit fructose, ajax antibacterial dish soap msds. Hmm - now that is tricky. Your EEI could look at the fermentation rates of glucose and fructose separately - keeping everything the same except the independent animal allergies homeopathic of initial concentration.
An then look at a mixture - or just look at sucrose as a natural mixture. What are you going to measure? The progress of the fermentation can be assessed by measuring the concentration of residual sugar or of the ethanol, or by the amount of CO 2 produced. The density can also be used as an index. You could also monitor the reaction with a gas pressure sensor. There are lots of other gas sensors too, ajax antibacterial dish soap msds.
Reducing sugars in wine 9. Carbon dioxide by titration Polyphenol Index or Permanganate Index Tests for reducing sugars British Nutrition Foundation ajax antibacterial dish soap msds Bottles of wine usually show the words "contains sulfites". Sulfites are widely used in winemaking as a preservative to protect wines from oxidation and microbial spoilage but some people are sensitive to them.
A friend of mine has enjoyed white wine with sulfites for decades without a problem, but has become sensitive in his older age. This sensitivity can cause a reaction that range from mild to severe: Thus, the government requires labeling of any food or beverage with a sulfite concentration of more than 10 ppm.
These three species are pH dependent but in wine with a pH of the first two species homeopathic anti fungal creams. But you need the right amount: Two titration methods for the analysis of sulfur dioxide can be downloaded here.