It’s been a tough couple of weeks for Moscow Mule lovers. The simple and delicious mix of vodka, ginger beer, and fresh lime juice is the perfect antidote to August’s heat and humidity. But the concoction has recently been called poisonous. What’s a drinker to do?
The trouble began with a report from the Iowa Alcoholic Beverages Division about the toxicity of the traditional copper mugs it’s served in. This news has given many drinkers a sobering scare. (That’s not to mention giving rise to a spate of doomsday headlines about copper poisoning and stories warning you to dump the mugs.)
But don’t throw out your mugs just yet! Chances are, they’re lined with food-safe tin or nickel. And even if they’re not, the science linking Moscow Mules to copper poisoning is fuzzy at best.
“If you have an acidic pH, some [copper] can leach off. Possibly,” says Svetlana Lutsenko, Ph.D., a professor at Johns Hopkins University and a researcher focusing on the mechanisms that regulate copper concentration in the human body. “This all needs to be tested because without facts we do not know whether it is a problem or not,” she says.
Copper, as Lutsenko reminds me, is “biologically very important.” You need copper to manufacture compounds, such as norepinephrine, so without enough copper you can get depressed. Our cells produce energy and metabolize iron because of copper. There’s actually a daily recommended allowance of 900 micrograms a day; also, she says, “moderate to mild copper deficiency may occur more widely than currently appreciated.”
Safety depends on dosage as is the case with alcohol or chocolate or coffee. “You’ll be fine with a cup of coffee, but with 10 cups you may not feel so well,” she says.
In any case, it’s unlikely that the copper in a Moscow Mule leached from its mug will take you down. As Lutsenko (who obtained her doctorate in physical chemistry in the Institute of Bioorganic Chemistry in Moscow) explains, there are multitudes of mechanisms that buffer against and eliminate excess copper if it happens to enter the body. “We have a sophisticated copper balancing system,” she says.
Bonnie Ransom Stern, Ph.D., a Washington, D.C.-based consultant on health sciences and risk assessment, also notes that some of the symptoms the recent news articles have warned against are overblown. Yes, going into a coma can be one of the syptoms of copper poisoning, but that typically occurs only in people attempting to commit suicide by drinking liters of copper solution, she explains. “Experiments where copper was added to drinking water found that around 6 mg. in a liter starts to induce adverse affects in some people,” says Stern. “Unless you let the drink sit for hours, it’s unlikely to reach that level.” If it does, you might feel nauseated or get the runs, only because the cells in your stomach got rifled up, but that goes away fairly quickly, she says, and, unless you have a genetic disease that can’t process copper (which your doctor would have likely informed you about long ago), the problem wouldn’t be systemic. Plus, she adds, your drink would start to taste metallic and bitter before enough copper is in there to cause a problem.
So, how ’bout a round of Moscow Mules in big fat copper mugs for everyone? “Absolutely,” Stern says, “I’ll drink more than one, and it wouldn’t worry me at all.” Lutsenko would join her. “Totally,” she says. “Without hesitation.” In fact, she had even bought one of those boxed Moscow Mule sets, complete with copper mug. “I thought it was cute,” she says.