The 1 Dead Giveaway You're Drinking Beer From A Dirty Glass At A Bar

The trick is to pay attention to what the bubbles are doing.

Half the draw of going out to bars and restaurants (for some of us, anyway) is that you’re paying someone to take care of the dishes for you. And while these establishments typically have cleanliness down pat, accidents happen, and sometimes you’re served a beer with someone else’s lipstick on the rim.

Even absent any obvious smudges or smears, beer professionals can tell just by looking if a beer has been poured into a dirty glass. The trick is to pay attention to what the bubbles are doing.

“Bubbles clinging to the inside of a glass where it meets the liquid part of the beer are usually a sign some residue, such as grease, dust, leftover beer or detergent, is present,” said Sara Hobday, head of beer research and curriculum at the Wine and Spirits Education Trust, the authority that certifies sommeliers and other beverage professionals.

(For the perfect visual example of bubbles clinging to the inside of a dirty glass, check out these photos.)

But, you may be thinking, beer is a carbonated beverage. Shouldn’t I be able to see some amount of bubbles in the glass? Indeed, you should — but where and how that carbonation appears can tell you if a glass is perfectly clean or if it could use another run through the dishwasher.