Question for the Oenochemist

Others welcome of course, but intended for Mark.

I tyipcally use Oxyclean to wash my stemware and decanter. I noticed on many occasions that when Oxyclean-infused water comes into contact with red wine residue, the water turns what appears to be cobalt-blue. What's the explanation for this Mark?

Thanks!

I'm not a chemist, but I think I remember enough from University to answer your question. The pH change caused by the oxyclean/water solution changes the color from red/purple to blue. If you live in an area with especially hard water, you will notice the same phenomenon when you rinse your glasses. Better living through chemistry!

http://antoine.frostburg.edu/chem/senes ... wine.shtml

check out this link and scroll down to "why roses are red and violets are blue".

Another neat experiment you can run, if you have hydrangeas growing, is to water one plant with a mild basic (alkaline) solution and the other with a mildly acidic solution; the acid-watered plants' flowers will turn blue while the alkaline-watered plants' flowers will turn pink.

I'm not Mark, FWIW, many home wine makers use dilute Oxyclean to sanitize surfaces that may come in contact with wine, especially, porous surfaces. Chlorine bleach can be used on non-porous surfaces, but require a thorough rinse. That being said, Oxyclean is an alkaline. The pigments in red wine change color wrt the pH, so that's why it changes. I once read an article (online) about anthocyanins and pH that described this, but can't seem to find it.
EDIT: Here's a good link: http://en.wikipedia.org/wiki/Phenolic_content_in_wine
From the link:

The color variation in the finished red wine is partly derived from the ionization of anthocyanin pigments caused by the acidity of the wine. In this case, the three types of anthocyanin pigments are red, blue and colorless with the concentration of those various pigments dictating the color of the wine. A wine with low pH (and such greater acidity) will have a higher occurrence of ionized anthocyanins which will increase the amount of bright red pigments. Wines with a higher pH will have a higher concentration of blue and colorless pigments. As the wine ages, anthocyanins will react with other acids and compounds in wines such as tannins, pyruvic acid and acetaldehyde which will change the color of the wine, causing it to develop more "brick red" hues. These molecules will link up to create polymers that eventually exceed their solubility and become sediment at the bottom of wine bottles.

I’m sure most of us are familiar with the “info-commercials” that demonstrates the “power of oxygen” using the classic Landolf Clock Reaction.
By simply pouring two solutions together chemical reactions will take place (not all at the same time, depending upon how quickly you pour them together and how well you mix them). Basically by simply mixing a solution of oxiclean with a little wine you are “bleaching” or “oxidizing” the wine (or the components of the wine, not all at the same time however). My guess would be that the oxiclean would first react with the SO2 in the wine (oxiclean most likely has some starch (good color indicator) as an ingredient) that’s why upon immediately mixing the two solutions it turns a “blue-ish” color.

Salute

Expanding on what Peter says above, you don't even need Oxycleen to see this if you have hard water. I've often noticed the last few drops of red wine left in a glass turning blue/violet as soon as I pour a bit of tap water in the glass to rinse it. The pigment molecules must be weak acids/bases which have somewhat different colors if they are predominately in the ionized or protonated state (this is the basis of pH indicator dyes, too).

Expanding on what Peter says above, you don't even need Oxycleen to see this if you have hard water. I've often noticed the last few drops of red wine left in a glass turning blue/violet as soon as I pour a bit of tap water in the glass to rinse it. The pigment molecules must be weak acids/bases which have somewhat different colors if they are predominately in the ionized or protonated state (this is the basis of pH indicator dyes, too).

Yep...depending on the ionization of the anthocyanin molecules (they come in red, blue and colorless) or the pH of the solution, the red or the blue will predominate. The anthocyanins act like a very narrow range litmus paper.

What all the rest have said, Ryan. The anthocyanins in wine are essentially the same as those found in hydrangeas (and, for that matter, the original litmus paper) and change color in response to changes in pH (red= acid, blue= base). Red wine is usually red (except when it's purple ) because the pH is between 3-4 (and that's why low acid New World wines look more purple than red), but if you look at red wine stains on teeth, they look bluish purple because the interior of your mouth is alkaline (pH 10 or so). OxiClean, being the trade name for sodium peroxycarbonate, is almost as basic as baking soda and so changes the color of your wine dregs faster than you can say Billy Mays.

p.s. Sorry for the slow response, but I've been quite busy as the organizer of this event.

Mark Lipton, resident oenochemist

Thanks everyone for the great responses, and to Mark for tying it all together. Actually, I find the fact that pH partly determines wine color an even more interesting concept that the original explanation of my question.