Moscow Mules’ unique cups probably aren’t poisoning you — but that doesn’t mean drinkers can sleep easy just yet.
Iowa’s Alcoholic Beverages Division recently issued an advisory bulletin warning against serving beverages in copper mugs. The reasoning: 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, including Moscow Mules.
“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.”
Copper poisoning, similarly to lead or other metal poisoning, occurs after a period of exposure. According to food poisoning attorney Bill Marler, it would take years to ingest a dangerous amount of copper by drink drinking Moscow Mules alone.
“You’d have to drink from a copper cup every meal of every day for 25 years,” Marler told Business Insider.
If you’re only drinking Moscow Mules occasionally — or even less than every day — you’re probably not going to be poisoned.
And, if you’re drinking Moscow Mules at every meal, everyday, copper poisoning may be the least of your problems.
“You’re at more risk for alcohol consumption,” Marler said.
Studies have found that that are health risks associated with even moderate drinking, which has been found to be linked to certain cancers and earlier death. Someone who drinks a Moscow Mule every day with every meal (21 drinks a week) would be classified as a heavy drinker, meaning that they would be at heightened risk of high blood pressure, heart disease, and liver disease.