from the works-on-both-whisky-and-whiskey dept.
There's nothing quite like the pleasure of sipping a fine Scotch whisky, for those whose tastes run to such indulgences. But how can you be sure that you're paying for the real deal and not some cheap counterfeit? Good news: physicists at the University of St. Andrews in Scotland have figured out how to test the authenticity of bottles of fine Scotch whisky using laser light, without ever having to open the bottles. They described their work in a recent paper published in the journal Analytical Methods.
[...] A 2018 study subjected 55 randomly selected bottles from auctions, private collectors, and retailers to radiocarbon dating and found that 21 of them were either outright fakes or not distilled in the year claimed on the label.
[...] Food scientists and chemists are also interested in using spectroscopy to identify the chemical compounds inside a whisky bottle. This involves shining a laser light into a substance, which scatters the light and breaks it into a spectrum of wavelengths.
[...] The challenge in applying such techniques to whisky is that the glass bottles themselves produce a large spectral signal, making it difficult to discern the chemical fingerprint of interest (that of the spirit inside). So spectroscopy is usually performed after whiskies have been removed from the bottle.
[The researchers] figured out how to shape the laser light into a ring instead of a focused beam, thereby suppressing the noisy signal from the glass.
Journal Reference:
Holly Fleming, Mingzhou Chen, Graham D. Bruce, et al. Through-bottle whisky sensing and classification using Raman spectroscopy in an axicon-based backscattering configuration [open], Analytical Methods (DOI: 10.1039/D0AY01101K)
(Score: 2) by driverless on Friday September 18 2020, @09:38AM (2 children)
As fake "extra virgin olive oil" (which most of it is) has taught us, the correct phrasing for any food counterfeit-detection mechanism isn't "we can now detect" but "we can currently detect until the counterfeiters change their mixture again to fool the check".
(Score: 2) by darkfeline on Friday September 18 2020, @10:06PM (1 child)
I don't think it's that trivial to trick spectroscopy. The best counterfeiters can do is make a bottle to block this technique, but that would itself be a giveaway that the bottle is counterfeit, unless the official product also switches to a bottle that blocks this technique (but why would they?).
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(Score: 2) by driverless on Saturday September 19 2020, @06:46AM
That's lab-grade spectroscopy run by experts. What'll be deployed isn't that but the cheapest possible automated process that sort of more or less gives a mostly OK result.
If it even gets deployed. For example in the case of olive oil since the international standards group for olive oil is very heavily influenced by major producers of cheap rubbish oil, they've rejected good tests like DAG and PPP and stuck with far less powerful, more easily-fooled tests that allow adulterated crap to be sold as high-quality oil.
So just because a test exists doesn't mean it'll get deployed, or if it is deployed that it'll be done in a form that can't be fooled.
(Score: 0) by Anonymous Coward on Friday September 18 2020, @09:46AM
1st world problem.
Not to worry, it will soon devolve into a 3rd world one and the problem will just disappear.
(Score: 2) by DannyB on Friday September 18 2020, @02:16PM (3 children)
Why would anyone want to drink Whisky or any alcoholic beverage, at all, but especially during a pandemic?
It's better to drink the kool-aid.
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(Score: 1, Funny) by Anonymous Coward on Friday September 18 2020, @03:51PM (1 child)
Indeed, mine's a bottle of Highland Park 19 y.o. kool-aid...
(Score: 0) by Anonymous Coward on Saturday September 19 2020, @04:51PM
Make America Grape Again!
(Score: 0) by Anonymous Coward on Friday September 18 2020, @05:55PM
No it's not. My favorite mixed drink is composed of equal parts diesel, Marvel Mystery Oil, and isopropyl alcohol. I haven't thought of a name for it yet, because I keep passing out. Go figure.
(Score: 0) by Anonymous Coward on Friday September 18 2020, @10:14PM
As usual, the details are slim enough to be very confusing, or at least very unsatisfying to the physics-inclined mind.
This is a Raman spectroscopy technique. With Raman spectroscopy you focus a laser on a material and you look at the light that comes from it to see what molecular excitations have occurred, and then you look up the spectral signatures you see to determine the material you're looking at. This particular technique uses backscattered light where you shine a laser on something and you look at the light that reflects back. Normally you would put your sample in a test vial because keeping it in the bottle allows whatever impurities are in the bottle glass to imprint a signature on what you're seeing from the whiskey. Apparently most bottles used for spirits are "Raman active", which cause high background signals if you're trying to look at the spirits inside them.
This particular setup uses an axicon lens [edmundoptics.com], which looks like a normal lens on one side, but it has cone-shaped glass on the other. What this does is it focuses light in a cone shape. If you go past the focus, the light as it propagates goes out in a very nice ring shape. They use this ring of light as their source and they bring the ring of light to a focus in the middle of the whiskey bottle; however, as the excitation light passes through the bottle glass it is not yet in focus and is still a ring. So the light comes to a focus in the whiskey, but they look at the backscattered light through the hole in the ring. Any excitation signals from the glass aren't part of the backscattered light to the detector. Using this approach over regular Raman knocks down the signal from the bottle by better than a factor of two.
(Score: 0) by Anonymous Coward on Friday September 18 2020, @10:18PM (1 child)
Why does my whiskey taste like someone's been shining lasers on it?
(Score: 0) by Anonymous Coward on Friday September 18 2020, @10:34PM
You dumbass, it's because you ordered the light whiskey [blogspot.com].