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Drinking beer straight from the bottle is very dangerous

Hygiene, gas and bacteria: the hidden risks of drinking beer without a glass

I am an epidemiologist by profession. The other day, after leaving my research center and before going home, I decided to stop for a beer to clear my head a bit, at a bar that is relatively close by, on one of the busiest and most stately streets in Prague. I was surprised when I ordered a specific beer, a Van Pur Premium: it is a light pale lager, with a golden color and white foam, a malty aroma with floral and herbal hop notes, and a balanced bitterness with a sensational flavor. But my surprise was complete when it was served to me in the typical ice bucket… but without a glass.

I stood there watching and noticed that several customers were drinking straight from the bottle. Obviously, I called the waiter over and asked him to bring me a glass, while also asking why they no longer serve that transparent glass object that allows you to pour the beer into a container, regulate the foam, and carry out the oxidation process and partial elimination of gas and impurities. The waiter did not really know what to say. He told me that a couple of weeks earlier, the owner had instructed that from that moment on, they should not provide that extravagant element commonly known as a beer glass… unless it was expressly requested. Which I did.

And the thing is, a few days later the same phenomenon occurred in another good establishment. It is clear that for pubs and bars there is an advantage: fewer glasses, fewer breakages, fewer dishwashers, less cleaning time. But it is surprising that customers, in general, almost like unthinking little animals, adapt to the custom without questioning it. Not only for reasons of manners, which also matter; it is not pleasant to see mouths attaching themselves to bottles as if they were baby bottles, although that is anecdotal. There is also the loss of enjoyment of flavor and appreciation of the beer’s values and qualities: aroma, foam, texture, real temperature… everything changes when there is no glass.

But what is important, what is truly serious, is something else: hygiene and health.

The bottle neck: the “dirtiest” part of a drink

When you drink directly from a bottle, you place your mouth precisely on the area that has the most contact with the outside: the neck. And that neck has had a long life before reaching your table.

From the moment the bottle leaves the factory until it reaches your hand, it usually passes through a logistics chain: pallets, trucks, intermediate warehouses, back rooms, cold storage, deposits. Along these routes, bottles may be exposed to dust, splashes, dirty surfaces, hands, reused boxes and, in some cases, facilities with pest control issues. There is no need to imagine horror movies: it is enough to remember that a warehouse is an ecosystem. Where food and drink are stored, there is a risk of insects and rodents. And where there are rodents, there is potential environmental contamination; they do not need to “bite” a bottle for their surroundings to be a problem.

It is worth being precise here: the real risk for a healthy consumer in a decent bar may be relatively low, but it is avoidable, and what is concerning is the normalization of “drinking from the outside” without even a minimal hygienic barrier.

What types of infections could be transmitted?

Most problems would not come from “the beer itself”, which due to its composition is not the best breeding ground for many bacteria, but from whatever is on the outside of the glass that comes into contact with your mouth.

Gastroenteritis: microorganisms that cause diarrhea and vomiting can be transmitted through fecal–oral contamination via dirty surfaces (not glamorous, but it is the classic route).

Respiratory viruses: if a bottle is handled by many hands and ends up in your mouth, it becomes a perfect bridge for viruses transmitted by indirect contact (especially if you then touch your face).

Cold sores and other contact infections: sharing bottles or mixing them up by mistake on tables is a classic.

Skin or mucosal infections: small cuts on lips or gums are entry points if there is contamination.

There is no need to panic, but it is important to understand a basic idea of epidemiology: probability multiplies when we repeat a behavior thousands of times. It is not “this beer”, it is the generalized habit.

Gas: drinking straight from the bottle introduces more CO₂ and your body notices

In addition to hygiene, there is the physiological issue: drinking beer directly from the bottle usually causes you to swallow more gas.

Why?

You do not “break” the CO₂ through the fall into the glass and the controlled formation of foam.

The narrow neck makes you drink faster and take larger gulps.

More air and gas mix in each sip, and your stomach becomes the container for that pressure.

Typical result: bloating, belching, reflux, gastric discomfort;
and in sensitive individuals, worsening of gastritis or acidity. The glass (or mug) is not a whim: it is a tool that allows the beer to release part of its gas, allows the aroma to emerge, allows the body to receive it better, and makes the experience cleaner and more pleasant.

“But I’ve been drinking like this all my life, and nothing has happened to me”

That is the phrase I hear most often in public health. And it is true… until it isn’t.

Epidemiology does not work with individual anecdotes; it works with populations and repetition. Many habits do not make you ill “always”; they make you ill “sometimes”, and in many cases, beyond infections, organisms are damaged over time in a silent way. And when a bar decides to eliminate glasses as a system, it is pushing hundreds of customers toward a less hygienic practice purely for operational convenience.

What to do (without dramatics)

Always ask for a glass. Without embarrassment, just as we ask for clean cutlery.

If it is served without a glass, demand one. If the bar feels uncomfortable, ask yourself why. If you are at home and decide to drink from the bottle (because yes, sometimes you feel like it), at least: rinse the neck with water and soap, dry it with a clean napkin, and avoid sharing it. If you have reflux, gastritis or are prone to bloating: glass, no exceptions.

Conclusion

A bar not wanting to clean glasses may be “efficient”. A customer accepting to drink from the exterior of a bottle as if it were normal is not. There is a difference between being flexible and giving up the basics.

The beer glass is not extravagant: it is hygiene, it is health, it is flavor, and it is culture.

And if someone looks at you strangely for asking for a glass, remember something simple: you are not being fussy; you are being sensible.