If you’re a big fan of breweries, you might have noticed that many places have a glass rinser installed in the bar. Before the bartender pours your beer, they’ll flip the empty glass upside-down over the rinser, which will—you guessed it—rinse out the glass.

It doesn’t exactly seem like the most effective way to sanitize a stein that could’ve been used by a dozen other people just that night, right? Luckily for all of us, especially during flu season, the rinser isn’t actually meant to clean glasses, and whatever bar you’re at almost definitely runs everything through the dishwasher first.

According to VinePair, the glass rinser serves a few equally important purposes. One, it washes out any leftover dishwasher detergent or dust that might have settled in the glass, ensuring that you only taste refreshing, yeasty deliciousness.

Rinsing a glass right before filling it with beer also makes it more slippery, minimizing the friction between your beer and the glass and maximizing your chances of a smooth, even pour. A perfect pour can give your beverage the perfect head (the foam on top of the beer), too. Though getting a faceful of froth may not seem ideal, VinePair explains that those tiny bubbles release fragrance when they pop, and smelling the full, nuanced aroma of your beer can definitely enhance its taste.

And lastly, a nice cold rinse can lower the temperature of your pint glass, keeping your beer cool for a little longer. Since pint glasses don’t have handles or stems, you have to hold them with pretty much your whole hand—which warms your drink faster than it would in a wine glass. Starting out with a cold glass can definitely help.

Wondering what else you might’ve gotten wrong about everyone’s favorite fermented beverage? Find out the truth about 11 other common beer misconceptions here.

[h/t VinePair]