Since announcing this week’s Booze of the Week is vodka, I was asked by a friend “Why do I get such miserable hangovers from cheap vodka, but not from premium vodka?” This is a question that has had scientists at each others throats for years. My first response to this question is that if a person is drinking premium vodka, its because they want to enjoy their drink, so they tend to drink a LOT less. When you drink cheap vodka, you’re really only looking for one outcome: to get drunk. So the reason you get worse hangovers from cheap vodka as opposed to premium vodka is because you drank more of it! But that’s not what you want to hear. You want to hear about cogeners and fusel oils.
Cogener is the term used for acetone, acetaldehyde, and tannins produced during the fermentation process. These impurities, when ingested, can exaggerate the symptoms that present during a hangover. In other words, they make the hangover worse. A byproduct of the distillation process is a fun little liquid called fusel oil.
Fusel oil is present in the first and last few ounces of the distallate and has long been considered to be hangover-inducing at best, toxic at worst. Fusel oil isn’t actually oil, but higher order alcohols produced during fermentation that travel into the distilled liquid. While it hasn’t been proven that fusel oil is any worse for you than ethyl alcohol, there is also no proof that it isn’t.
There are many other contributing factors to a hangover, but these two are the only relevant ones to this conversation.
Cogeners are produced during the fermentation process, but tend to not pass through the distillation process. If they do, only small amounts will, and generally only through one (maybe two) processes. Fusel oil, will always pass through the distillation process, but will only be present at the beginning or end of the process.
Many premium vodka distillers will boast about how many times they distill and filter their vodka. To cut costs, the cheaper brands of vodka are only distilled once or twice, and may not even be filtered. The more you distill it, the less impurities will be present. The same goes for filtration.
So, there you have it. In short, cheap vodka gives you nasty hangovers because it has more impurities that make the hangover worse.