Help please! Science project question

[meganruby]

I have done a experiment testing the ethanol content in a white wine sauce after different cooking periods by titrating it and have gotten odd results. The sauce contained a cup of 13% alcohol volume wine and a cup of chicken stock and an onion. It was prepared and frozen until I was ready to test it. When I tested it my 0 minute cooking time sample (the one the hadn't been heated at all) got a result of 2% where as i expected it to be at least 6% as I thought most of the ethanol would have still been present. Do have any idea why I might have gotten these results?

[Marqq]

I have done a experiment testing the ethanol content in a white wine sauce after different cooking periods by titrating it and have gotten odd results. The sauce contained a cup of 13% alcohol volume wine and a cup of chicken stock and an onion. It was prepared and frozen until I was ready to test it. When I tested it my 0 minute cooking time sample (the one the hadn't been heated at all) got a result of 2% where as i expected it to be at least 6% as I thought most of the ethanol would have still been present. Do have any idea why I might have gotten these results?

 

How long was it frozen, and at what temperature (don't frozen aqueous solutions sublime)?

Also-- 1 cup 13% alcohol + 1 cup stock + ~2/3 cup onion = 2 2/3 cups, so that 13% alcohol is already down to ~4.875%.

Finally, how would the alcohol dissolved into the fat of the stock affect your results and the titration technique?

[WorldOfBiochemistry]

The preparation of the sauce, after the addition of the ethanol, how many time?

 

I have done a experiment testing the ethanol content in a white wine sauce after different cooking periods by titrating it and have gotten odd results. The sauce contained a cup of 13% alcohol volume wine and a cup of chicken stock and an onion. It was prepared and frozen until I was ready to test it. When I tested it my 0 minute cooking time sample (the one the hadn't been heated at all) got a result of 2% where as i expected it to be at least 6% as I thought most of the ethanol would have still been present. Do have any idea why I might have gotten these results?

[Vulgaris]

Ethanol won't freeze in a common freezer and will therefore evaporator despite the fact that the sauce was frozen. If you freeze a mix of ethanol and water you will end up with sort of a slush ice, as the water freezes but the ethanol stays liquid. Therefore, if you stored the sauce for even relatively short time I would suspect the ethanol content to drop significantly. Apart from that, you need to consider how other compounds in the sauce interferes with the titration. Some of the alcohol will move into the onion, is that taken into account? If there is any fat in the chicken broth (there probably is) some of the ethanol will be dissolved in that. Are you able to extract that in your titration method?

 

I would suggest to redo the experiment where you do a titration right after you prepared the sauce, excluding the freezing step. Just to see the effect of storage. If it's significant, consider either to avoid the storageing all together, or make sure to use glass containers (don't fill it all the way up or the glass will break when the water freezes and expands!). The ethanol won't be able to escape from the glass containers.

 

This shows why it is important always to include controls in your experiments! .

 

Good luck!