Why Does Darker Alcohol Like Whisky Cause a Worse Hangover Than Vodka and What Are Congeners?

A leaflet published by Health Scotland says the darker the color of the alcoholic drink, the worse the hangover would be.

Most people consume alcoholic drinks for their ethanol content.

However, many such drinks also contain amounts of other biologically active compounds known as congeners.

Congeners include complex organic molecules such as polyphenols, other alcohols such as methanol, and histamine. They are produced along with ethanol during fermentation or the drink’s aging process.

Congeners are believed to contribute to the intoxicating effects of a drink, and the subsequent hangover.

People who drink pure ethanol-based alcohols such as vodka have been shown to suffer fewer hangover symptoms than those who drink darker beverages such as whisky, brandy, and red wine, all of which have a much higher congener content.

The congener denounced as the main culprit in a hangover is methanol.

Humans metabolize methanol in a similar way to ethanol, but the end product is different.

Ethanol generates acetaldehyde, but when methanol is broken down, a major product is formaldehyde, which is more toxic than acetaldehyde and can cause blindness or death in high concentrations.

Ethanol inhibits the metabolism of methanol; this may be why drinking “the hair of the dog” can alleviate hangover symptoms.

Studies have found that the severity of different drinks’ hangover symptoms declines in this order: brandy, red wine, rum, whisky, white wine, gin, vodka, and pure ethanol.