Zythophobia (from Greek zythos, "beer") is the fear of beer. The #1 reason why they have zythophobia is that beers contain alcohol, which is an unhealthy stuff. Because beers are alcoholic beverages, zythophobia is considered a branch of methyphobia (fear of alcohol), along with oenophobia (fear of wine). Consuming beer and other alcoholic drink can lead to both short-term, such as difficulty in thinking, rage, fainting and loss of balance, and long-term effects, such as memory loss, kidney rupture, and heart failure. Another reason they fear beer is not their effects, but the contents in it, especially that beers contain fermented yeasts, giving them belief that there could be live yeasts in beers and consuming it would put parasites in the body leading to unpleasant effects.
Zythophobes not only avoid drinking beer, but not letting others drink beer in the vicinity, like in the room or even anywhere in the house. Zythophobes are usually afraid to have parties because beers are traditional served in parties. Since bars are public places where people drink beer, zythophobes would avoid going to bars, or in other words zythophobia can lead to tavernaphobia, fear of going to bar.