The Moscow Mule as been a popular cocktail for a while. The cute copper mug it’s traditionally served in makes it easy to spot this trendy drink in bars and restaurants.
The problem isn’t the alcohol or other ingredients in the drink, but in the vessel the Moscow Mule is served in. Copper can leach out of the cup, into the liquid, and then be digested by drinker, which causes a serious health problem in the form of copper poisoning.
FDA guidelines clearly state that copper should not be used to cook or serve acidic foods with a pH level below 6, like vinegar, wine, and pickles, for example. If the low acid food are in direct contact with copper, that’s when the toxic metal can leach into the food or beverage it’s prepared in or served in.
The recipe for Moscow Mules calls for vodka, ginger beer, and lime juice, which are combined and served in shiny, eye catching copper mugs. Those ingredients come in way under 6.0 on the pH scale, which is what is causing the problem.
“High concentrations of copper are poisonous and have caused food borne illness,” a bulletin published by the Iowa Alcoholic Beverage Division explains. “When copper and copper alloy surfaces contact acidic foods, copper may be leached into the food.”
If Moscow Mules are your drink of choice, you should be familiar with the symptoms of copper poisoning, which include diarrhea, vomiting, abdominal cramps and pain, and jaundice. Copper poisoning is not usually fatal, but is very uncomfortable, so see a doctor if you think you have it.
The good news is that Moscow Mules are perfectly harmless if served in mugs lined with stainless steel or nickel. The exterior of the cup can still be pure copper, but if it’s lined with a safe metal, the problem is solved, since the beverage won’t come into direct contact with the copper.
The origins of the Moscow Mule date back to a Hollywood bar in 1941. The bartender of the Cock ‘N’ Bull invented the cocktail when he was overstocked with cases of vodka and ginger beer that weren’t selling. The Moscow Mule has been gaining in popularity ever since.
So the next time you order a Moscow Mule, ask the bartender or waitress about the mugs, and take a look before you take a sip to make sure the cup’s interior isn’t copper, but lined with stainless steel.