And you thought the only risk was a hangover.
The state’s Alcohol Beverages Division issued the warning in regards to the copper mugs often used to serve the popular cocktail.
Turns out that the Food and Drug Administration’s Model Food Code prohibits foods with a pH below 6.0 from having direct contact with copper, and a traditional Moscow Mule—vodka, spicy ginger beer, and lime juice—has a pH “well below 6.0,” per the bulletin.
Although the advisory technically is directed toward Iowa residents, the risks are real for anyone who enjoys Moscow Mules in their traditional copper mugs.
According to Toby Amidor, R.D. and author of The Healthy Meal Prep Cookbook, when foods with a lower pH have contact with copper (like you'd find in a Moscow Mule mug), it leaches the copper out of the mug, which is dangerous to ingest.
“Too much copper can lead to nausea, vomiting, diarrhea, stomach pain, and metallic pain in the mouth. If you develop copper toxicity, though not very common, it can lead to heart problems, jaundice, coma, and even death,” Amidor says. “A doctor would conduct a test to determine if you have copper toxicity and then would prescribe a treatment to reduce the amount of copper in your body."
Moscow Mules aren’t the only thing that could lead to copper toxicity. “Copper pots have this same issue, especially when you’re cooking tomato sauce in them. They now line copper pots with materials like stainless steel so the copper doesn’t leach. The same idea can be done with the mugs,” Amdior says. “This has also been a concern with other metals and equipment such as lead from crystal bowls or glasses and pewter pitchers which are made from several metals that serve lemonade or other acidic drinks.”
Thankfully, you don't have to ditch your favorite hipster cocktail for good. You just need to switch to a copper mug that is lined with nickel or stainless steel, says Amidor.
These best-selling copper mugs from Amazon are a great choice if giving up your Mule is simply not an option.