G'day folks,
Or you may be able to just use food dye if you really wanted - I remember reading somewhere that many food dyes are somewhat petroleum based.
Although that could just be 'fake news' put together by some overprotective mothers group haha.
True as far as it goes, but there are water-soluble and oil-soluble versions of the food dyes, and I've only ever encountered the water-soluble versions on retail sale.
That water solubility property can be used for an easy spot check for the presence of ethanol in a fuel sample, though.
A few drops into a say 20-50mL sample in a glass jar; if the colour settles in a droplet to the bottom - ethanol-free. If the colour disperses through the bulk liquid, it contains ethanol for sure.
