Experts Are Sharing The 1 Dead Giveaway That You’re Drinking From A Dirty Beer Glass At A Bar

Another good sign to look for is called lacing. This is when that tasty, tasty foam sticks to the side of the glass as it empties. A clean glass, Hobday said, “allows for residual foam to stick to the walls as you drink your beer, forming a lace-like pattern of parallel rings on the empty glass.” 

A beer with no head, a head that fizzles out quickly or a beer that lacks visible lacing are all signals that your glass may not be what professionals refer to as “beer clean.” Smith mentions a couple of alternate explanations, though. 

“There is also the potential that the glassware is fine, but the taplines or beer itself is dirty or infected,” she said. Additionally, “there are very rare cases where taprooms still have cleaning solution left in the lines and this gets into the first beer pour of the day,” though this is most common at taprooms that offer self-pours, “where the consumer might not know what to look for when pouring a beer for themselves.” These cleaning solutions, she said, are typically blue or green, so in most cases it’ll be pretty obvious that something is awry.