Wednesday, October 25, 2017

Checking for Titratable Acids

Recently, my husband ordered a paper chromatography kit for checking the titratable acids in our wine. We did this because we want to conduct a malolactic fermentation (MLF) on our Chardonnay. So, we needed to have some way of "seeing" what acids are in our wine. This kit comes with standards for malic acid, lactic acid and tartaric acid. Using a special solvent that is provided with the kit, paper chromatography allows the separation of these acids. It is a qualitative, but somewhat semi-quantitative means of ascertaining what acids are present in the solution being tested (wine).
This is rather hilarious for me because my husband has a Ph.D. in Chemistry. So, he had to dust off some of the cob webs in his mind to harken back to a time (General Chemistry 101 and the associated lab), where he actually did a paper chromatography experiment.
The paper that is provided is called the "stationary phase" and the solvent is the "mobile phase". As the mobile phase is being drawn up the stationary phase by capillary action, the compounds (wine samples) in the stationary phase get separated.
These are the results that we got for our wines:
The samples are labeled on the x-axis and the y-axis shows how the tartaric, malic, and lactic acids separated from the various samples. Based on this method, it appears that Chenin-7 contains very little, if any lactic acid.
Since we are conducting our malolactic fermentation on Chard-2 (Chardonnay-2), we will keep this chromatogram to refer to as our MLF progresses.

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