[Tfrom]

Hello, this is my first post here!

Here is my situation: I need to do a relatively small presentation in class about what happens when you use cooking salt to treat a red wine stain.

Here is what I know so far:
Wine consists of many, many compounds and reactions between them basically happen all the time. Some of them, anthocyanidines are the main contributing force to colour intensitsy (red). Now, if I use cooking salt (sodium chloride, calcium carbonate, magnesium carbonate) and water on the stain, it becomes less visible over time, but there is also a blue hue that remains.

Now, where I need a little push in the right direction:

In my opinion, the blue-ish hue originates from the now alkalic pH (CO3- from the carbonates should give hydroxide ions). Am I right that the colour has to do with the structure of anthocyanidines that changes with pH? Any input is welcome here!

The decolouration as I understand it happens because sodium elutes the colour pigments from bigger polyphenolic compounds (pigments + copigments) and those now appear almost colourless-yellowish.

I hope my thoughts are not too vague but I need some confirmation/correction of my theories.

Big thanks in advance! Sorry for any mistake, not a native speaker.

[Borek]

the blue-ish hue originates from the now alkalic pH (CO3- from the carbonates should give hydroxide ions).

Kitchen salt doesn't contain carbonates.

[Tfrom]

Thanks for the reply! Yet my salt container has definately carbonates in it, at least it's listed as an ingredient. I think they are used as an abherent to increase pourability. Maybe additives differ regionally.