The number of breweries operating in the U.S. rose to an all-time high last year. The amount spent in the country on beer, too, experienced an increase — to a staggering $34 billion. Simply put, beer is America’s favorite alcoholic beverage. But not everyone likes beer, and it turns out there’s a scientific reason why.

Digital publication Live Science recently got to the bottom of the conundrum, after pulling studies and speaking to a New York-based professor on the topic. The publication concluded that there’s one reason some people can’t stand the taste of beer: bitterness.

One of the four essential ingredients in beer is hops. Scientifically known as Humulus lupulus, the cone-shaped flowers bring different flavors, including bitterness, to a brew. Just how bitter a beer tastes depends on the desired style and decisions made during the brewing process.

Bitter flavors are one of the five tastes that cells inside our taste buds can perceive (the others are sweet, salty, sour, and umami, or savory). We’re actually programmed to reject bitter flavors as our bodies link them to potentially harmful food, drink, and poisons.

Our mouths have evolved to contain 25 receptors for bitterness, compared to just two for salty. Genetic variations like the number or tastebuds a person has means some of us are extremely sensitive to bitterness (those are the ones who just can’t hop on the IPA train).

If you fall under this category, that’s a bummer. But look on the bright side: at least you’re less likely to be psychotic, as some scientists claim.