One of the best things about Moscow Mules is how cool and Instagram-worthy the copper mugs they’re served in look, right? Unfortunately, those snazzy cocktail cups could actually cause severe food poisoning, thanks to the way the copper reacts to the ginger beer, vodka and lime juice in the cocktail. Say it ain’t so!
According to a recent advisory bulletin from the Iowa Alcoholic Beverages Division, there is a strong risk of foodborne illness when copper comes into direct contact with food (or, in this case, drinks).
“Iowa, as well as many other states, has adopted the federal Food and Drug Administration’s Model Food Code, which prohibits copper from coming into direct contact with foods that have a pH below 6.0,” reads the bulletin. “Examples of foods with a pH below 6.0 include vinegar, fruit juice or wine. The pH of a traditional Moscow Mule is well below 6.0. This means copper mugs that have a copper interior may not be used with this beverage. When copper and copper alloy surfaces contact acidic foods, copper may be leached into the food.”
According to the National Institutes of Health (NIH), symptoms of food poisoning from copper include abdominal pain, diarrhea, vomiting and jaundice, or yellowing of the skin.
“Sudden (acute) copper poisoning is rare,” a spokesperson from the NIH told The Washington Post. “However, serious health problems from long-term exposure to copper can occur. Severe poisoning can cause liver failure and death.”
Luckily, the Iowa Alcoholic Beverages Division says there’s a very simple way to continue serving cocktails in the copper cups: Simply make sure the insides are lined with another metal, such as nickel or stainless steel, and you avoid the risk of copper poisoning while still looking too cool for school.