A few years ago I decided to get certified as a Cicerone—the beer version of a sommelier. During my studies, I learned what constitutes a “Beer Clean” glass. It was honestly something I’d never considered before. A clean glass is a clean glass, right? Wrong.
Things like detergent residue and lingering oils are pretty common on glassware, and they can alter the aroma and flavor of your beer—and their presence means that glass isn’t really clean. The good news is, there’s a really easy way to tell if that glass you’re drinking out of isn’t “beer clean.”
This hack comes with a downside: If you frequent dive bars or like to drink a beer or two at your average restaurant or airport bar, I’d recommend not reading any further. Once you know how to detect a dirty glass you won’t be able to avoid doing so, and I can tell you from personal experience that dirty glasses are pretty much everywhere.
Ok, you’re sure you want to know this? Really sure?
Alright, I warned you. You can tell a beer glass isn’t “beer clean” if you pour beer into it and bubbles cling to the sides. It will looks something like this photo below:
The head on your beer will also dissipate more rapidly in a glass that isn’t beer clean, and/or the foam won’t cling to the side of the glass as you start to drink:
This YouTube video does a solid job of giving you the full details:
The video (aimed at bartenders) also explains what to do to ensure you have a beer clean glass—if you’re the one cleaning it—going forward. You can tell if your beer glasses at home are clean by just dipping them in water. If the water coats the inside evenly, then you’re good. If you end up with droplets on the inside of your glass, it could be cleaner.
I learned all this a few years ago, and since then I think I’ve sent one beer back (the glass was covered in bubbles and the taste was honestly pretty awful). I wouldn’t recommend making a big stink about it unless your beer truly is awful. However, if you notice it happening more than once at your frequented watering hole, you might want to find somewhere else to drink.