Concentrating acetic acid from vinegar Vinegar seems to kill poison ivy or at least severely stunt their leaves. I am trying to increase the concentration of acetic acid and I put a bottle of vinegar in the freezer. I have looked at it and it has turned cloudy. I'm thinking if I poured this through a coffee filter I should be filtering out solid acetic acid. I might do this in the freezer because it might take some time. Does anyone think this will work? I might be getting water ice instead. Either way I would be separating the two. I could repeat this step and concentrate it further. Would I not really be filtering out anything? On another blog someone suggested buying aluminum acetate which has more acetic in it instead, but this might not be as effective.
If I understand correctly, what you described can be seen as a form of fractional freezing.

This is done in order to make alcoholic beverages more alcoholic (Eisbock is an example): the beverage is left to partially freeze and the ice is removed.
Since ethanol has a lower melting point (-114 °C) than water (0 °C), this effectively removes more water than ethanol.

But in your case, since acetic acid has a higher melting point (16 °C) than water, the solids will have a higher concentration of acetic acid and you would want to keep that instead of the liquid.