We’ve probably all been there. At the climax of a night of alcohol-fuelled revelry, an enthusiastic gesture knocks over a glass of wine. It tumbles, contents spilling onto the carpet and for reasons unknown, the wine is always red and the carpet grey.
The age-old advice of pouring white wine onto red is popular. It doesn’t work very well but people like it because there’s usually a bottle close to hand at a dinner party. And while it’s marginally better than dousing it with water, there are better and less expensive stain remover techniques.
There are a variety of ways that stain removers work. Generally speaking, they all rely upon dissolving the stain into a liquid. The liquid that does the dissolving is called a solvent. In this instance, the solvent is white wine and the stain is the red wine pigment.
A solvent can be water-based or oil-based. As you probably know, oil and water don’t mix, so you need to use a water-based stain remover on a water-based stain, and an oil-based solvent for an oily stain (WD-40 can dissolve many greasy stains, for example). This can be remembered as ‘like dissolves like’.
White wine is better at removing stains than water because of the alcohol it contains. Alcohol is great for removing both water-based and oil-based stains and is in all sorts of cleaning products. The chemistry is a little complex, but the alcohol molecule has two ends: a ‘polar’ end – meaning it has a charge – and a ‘nonpolar’ end that has no charge. The charged end helps to dissolve water-based things and the un-charged end dissolves oil-based thing. Alcohol also serves as a good stain remover because it has a low surface tension. Compared to water, alcohol will spread over a wider area, and cover the stain easily.
But before you pour that bottle of vintage Chardonnay all over your carpet, it is worth remembering that wine isn’t a particularly good stain remover. One experiment (conducted by a student) found that white wine ranks low down on the list of all available stain removers. Commercial stain removers are far more effective and versatile as they usually contain emulsifiers (which help dissolve fats), surfactants (which help further lower surface tension), enzymes (to break down the stain molecule itself) and/or whiteners (to mask the stain).
The alcohol content of white wine isn’t particularly high either, so if you want a drink that will get rid of the stain faster, then go for some gin or vodka.
Then again, that stain doesn’t look all that bad after all…
Answer by Dr Stu
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