You. You're out drinking with your friends, matching them round for round. They're sippin' fancy whiskey, but you're saving money, sticking with the well specials. So why is it, halfway through the night, you're suddenly hit with a brutal headache, and everybody else is fine?
You've made it through the long week, and it's time for Happy Hour, Gizmodo's booze column. A cocktail shaker full of innovation, science, and alcohol. Shhhh, my brain!
First off, let's set the record straight. Just because something is inexpensive, that's doesn't necessarily mean it's bad. Tito's vodka, for instance, doesn't cost much, but it can go head-to-head in flavour and purity with uber-expensive topshelf brands. So when we say "cheap" what we really mean is "low-quality." That said, Tito's is more the exception than the rule, and cheap stuff is generally more likely to be low-quality.
Congeners, also known as fusil oils, are a byproduct of the mash fermentation process. They are, essentially, impurities. There are hundreds of types of congeners, some of which are higher-order alcohols (i.e. non-ethanol) that our bodies can't really process. Essentially, our bodies treat them as a poison, and a headache is a very common symptom of poison processing. That said, different people may be better or worse at metabolising and flushing these toxins.
Because all alcoholic beverages begin with fermentation, any type of booze is liable to have congeners. It is widely believed that because cheaper alcoholic beverages begin with lower-quality ingredients, more congeners are likely to be produced at the fermentation stage.
Say you have a big vat of fermented liquid and you want to turn it into a high-proof spirit. That means distilling it. Each time it goes through the distilling process, more and more congeners and impurities (which may cause headaches) are removed. Tito's, as an example again, is distilled six times. If you are buying bottom-shelf vodka, you'll be lucky if it was distilled twice. This process lends some credence to the idea that the cheap stuff is harder on your brain.
Filtration is another way that vodka brands attempt to clear out impurities. We made an activated-carbon filter and ran some terrible vodka through it. It actually made the booze a lot better. Bottom-shelf brands typically do the minimum for filtration because they're made en masse, and, after all, nobody is buying Georgi for the subtle and nuanced flavour.
Darker spirits, like brandy, whisky, and cognac, tend to have higher concentrations of congeners than their clear brethren—vodka, gin, or white rum. (Tequila is an exception.) This isn't a cheap vs. expensive thing, though, it's simply a difference in the distillation process. The mark of a good vodka is no flavour, whereas whiskey should have a distinct flavour.
Congeners are an important part of that equation. An experienced distiller actually cuts the spirit with trace parts of the congener-heavy parts of the distillation run. In the right quantity, it gives whiskey its characteristic bite. Whiskeys are also barrel-aged. As the spirits sit in a barrel over a period of months or years, the liquid leaches flavour, colour, and other chemicals out of the wood. This may be even more exaggerated in bourbon, which is aged in charred barrels.
These chemicals all affect different people in different ways. But the major distinction between high and low-end whiskeys (or whiskys, if we're talking Scotch) begins with what happens before it goes into the barrel for aging. It depends on the quality of the grains used from the outset, and thus how pure the distillate is in the first place. It matters how careful the distiller is with the way the spirit is cut. Distillers can still bottle up a whiskey made with a dirtier spirit—you can simply mask the problems with the intense flavours of barrel ageing.
You often hear that cheap red wine causes the worst headaches. There is actually a medical term called Red Wine Headache. The thing is, its exact causes are not understood, and the comparative price of a wine doesn't seem to be a factor, as every extremely expensive wines can cause Red Wine Headache. The leading cause seems to be histamines, which are present in grape skins. White wine, which is made without the skins, has far fewer histamines in it, and is much less likely to cause a headache. The histamine content can change from vintage to vintage. A year of bad growing weather can cause a significant spike in the histamines produced, and so a wine that didn't give you a headache last year can make a bomb go off in your brain this year.
Another factor is sugar content. Here is a time the cheap wines may be a culprit—they're often very sugary. Something like a cheap wine cooler may even have sugar added to it. Adding sugar to grape juice can accelerate the fermentation process, but this typically leads to an inferior type of alcohol. Also, the added sugar will cause a spike in your blood-sugar. When it comes crashing down, headaches are a common side effect. Liqueurs, candy-like spirits, and very sweet cocktails may have the same effect.
Drinking any alcoholic beverage, especially to excess, can lead to a headache and a bad hangover. The root of it all is dehydration. Alcohol is a diuretic. It makes you pee more, which means less water for your internal organs. Your organs then try to borrow water from anywhere they can, including your brain. As your brain dehydrates, it slightly contracts. This strains the connective tissue that holds your brain in your skull, resulting in a screaming headache. In other words, stay hydrated as you drink. Don't wait for the headache to start coming on. Once you're suffering, it can be difficult to recover, even if you pound water faster than a round of free shots.
Ultimately, if you're going to be drinking, you're putting your brain in harm's way. But evidence supports splurging on the good stuff. So when your wife wants to know why you blew all that money on a nice bottle of bourbon, just pour it neat and raise a glass—to your health, honey.