Raman spectroscopy has been used to analyze beer before. There’s even a undergraduate exercise that will let a student calculate the percent alcohol in a sample. I want to try it. It’s definitely not just an excuse to try a bunch of different beers.
Raman is like the complement of IR spectroscopy. People are familiar with IR spectroscopy because it is commonly used in organic chemistry classes. Raman is better for aqueous samples than IR (usually) so it makes sense to apply it to beer. This spectrum adapted from Zou et al shows why. The peaks for ethanol are nicely distinguishable above a low background from water.
There are nice hand-held Raman instruments that will give all kind of useful information about a unknown substance. It has been used for things like law enforcement (is that powdered sugar or freebased adrenal glands?) and Department of Defense business. So it’s natural to apply it to beer. It should be possible to amass a big database of beer spectra, annotate it, and mine it for useful information.
But what we need is a cheap instrument that beer enthusiasts can use to take spectra and contribute. A Beer-o-scope or Beercorder. I’m not sure about the name. But as fun as that sounds, I do need to make sure it will work. To the lab!