Practical investigations
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I'm investigating wine and having real trouble discolouring red wine with activated charcoal. I know it’s supposed to work and the charcoal does need to be activated. But can the process be speeded up by: heating wine 35°C, adding acid, and powdering the activate charcoal, and then stirring for five minutes? Do you also know if adding PVPP (polyvinylpolypyrrolidone / polyclar) works? Many times thank you!
Igloo writes ...
Heating wine will cause its volatile components to vaporise away much more readily, so the use of heat to improve the efficiency of activated charcoal is probably not a good idea. If you are analysing the wine for the ethanol content, the concentrations of acids of low molar mass or esters, for example, the wine does need to be kept relatively cool, otherwise your results will appreciably underestimate the concentrations.
My advice would be to try another “brand” of activated charcoal. There are several types available, e.g. wood charcoal, animal charcoal, etc., and if you’ve had little success with one, why not try another? Experience shows that old samples of activated charcoal are unreliable. Try to use a freshly purchased sample, if possible.
As for the use of PVPP, this sounds like a very good idea. PVPP products are known to remove polyphenols (which cause turbidity) from beers and tannins from plant extracts and since the colour of red wine is mostly caused by the presence of tannins and partly by polyphenols, I’m sure that PVPP is worth trying.
Always carry out a risk assessment and check with your teacher before starting any practica work.
Risk assessment
Before attempting any practical work based on the advice and suggestions on this website, you must do the following. Identify any hazards, assess the risks from these hazards, and then decide appropriate control measures to reduce the risks. You must have these approved by those in authority in your school or college laboratory. Do not rely on what is said on this website.
For further guidance see our tutorial on Risk Assessment.
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updated: 02 March 2006
