What To Do When There's A Fly In Your Glass Of Wine

When a dead fly is discovered in soup, proper restaurant etiquette dictates a specific customer response: alert the server, and discreetly request a replacement. This request should, of course, be honored, and often the restaurant will not charge for the affected item. Hygiene is the driving force behind this strong response. According to a 2004 study from the "International Journal of Food Microbiology," flies can transmit harmful bacteria, including foodborne pathogens like salmonella and E. coli.

However, the etiquette differs if a dead fly is found in a glass of wine. Why? For several reasons, including the fact that wine possesses properties that reduce the risk from harmful bacteria that flies may carry. Flies, more commonly fruit flies in the case of wine, are also unlikely to affect the wine's taste. Therefore, if you're not too squeamish, the appropriate action is to calmly remove the intruder and continue as if nothing unusual has occurred.

If you are disturbed by such an occurrence, or if you believe you can detect a taste difference, then it's perfectly acceptable to ask for a fresh glass.

Why the fly etiquette is different for wine

Wine possesses antibacterial properties, but that's not the sole reason the risk of infection is so minimal. Wine also contains alcohol, phenolic compounds, and is acidic, with a low pH level. As a 2020 study from the journal "Foods" indicates, these factors collectively work to impede the development of foodborne pathogens such as E. coli.

Of course, even though wine drinkers face a lower risk of infection from bacterial pathogens, this risk is not entirely eliminated. If a glass were to contain enough flies, they could potentially deposit a sufficient quantity of bacteria to reach the threshold for an infectious dose. Yet, the likelihood of a single fly causing this is very low.

What's more, the human body provides an additional layer of protection, primarily thanks to its stomach acids. Pathogens generally do not tolerate acids well, as these can disrupt their DNA structure. Pathogens also dislike cold environments. Therefore, chilled wines offer yet another line of defense, further reducing the likelihood of potential infection.

The taste difference in wine is negligible

Some wine connoisseurs claim that they can detect the difference a single fruit fly makes to the taste of their wine. However, in most cases, a fly won't noticeably change your drink's flavor, and it's unlikely that non-experts — even those who have experience in blind wine tasting — would detect any difference. This, of course, doesn't mean finding flies in your wine is enjoyable. In fact, some enterprising entrepreneurs have even capitalized on consumers' aversion to these unwanted intrusions by marketing preventative wine covers. But if a fly does happen to drop into your glass, there's really no need to immediately call over the server or sommelier.

That being said, if you do happen to notice a subtle difference in taste, by all means, feel free to politely request a replacement for your current glass of wine. In all likelihood, your request will be promptly honored.