Half the fun of ordering a Moscow Mule is the copper mug in which it's served. According to cocktail lore, the gleaming metal vessels keep your drink extra cold and meld the flavors of vodka, ginger beer and lime together in a way no glass can. (Honestly, this is all bunk, but the mug is super Instagrammable.)
But now we have bad news for fans of the flashy gingery coolers: A recent bulletin out of Iowa brings the safety of that ubiquitous copper mug into question.
The Iowa Alcoholic Beverages Division released an advisory bulletin last week explaining that “High concentrations of copper are poisonous and have caused foodborne illness.” The bulletin’s primary purpose was to warn drinkers and bar and restaurant workers of the potential dangers of drinking the cocktail out of untreated copper. The report points to the FDA's Food Code, which states that "copper and copper alloys such as brass may not be used in contact with a food that has a pH below 6 such as vinegar, fruit juice, or wine."
The report goes on to explain that “The pH of a traditional Moscow Mule is well below 6.0.”
So what does that mean for your recently acquired, verging on obsessive Moscow Mule habit? Well, probably not much—namely because most eating and drinking establishments use copper mugs that are lined with perfectly safe metals, including nickel and stainless steel. So all you have to do is make sure you’re sipping out of one of these lovely nickel-lined vessels, and you can drink easy, knowing that the odds of getting poisoned by your favorite drink are slim to none.