Moscow Mules could be poisoning drinkers.
Or, to be more exact, the copper cup that the drinks are traditionally served in might be.
Iowa’s Alcoholic Beverages Division issued an advisory bulletin warning bars and restaurants against serving Moscow Mules and other beverages in copper mugs.
Iowa follows the Food and Drug Administration’s code that prohibits copper from coming into direct contact with acidic foods with a pH below 6.0. That includes vinegar, wine, and Moscow Mules, which are traditionally made with vodka, ginger beer, and lime juice.
“High concentrations of copper are poisonous and have caused foodborne illness,” the bulletin says. “When copper and copper alloy surfaces contact acidic foods, copper may be leached into the food.”
Over time, copper exposure can damage the liver and kidneys. In instances of acute copper poisoning, which is uncommon, someone who has consumed copper may experience nausea, vomiting, abdominal pain, and liver failure.
But according to Bill Marler, a lawyer who specializes in food-poisoning cases, copper poisoning from drinking Moscow Mules would take years to develop.
It makes sense that the FDA would try to prevent people from being exposed to excess copper, Marler said, especially because some people are additionally exposed in other ways, such as through water pipes. But to get copper poisoning from Moscow Mules alone, he said, a person would have to be drinking from a copper cup “every meal of every day for 25 years.”
“You’re at more risk for alcohol poisoning,” he said.