Officials say those Moscow Mules could have a sickening kick if you’ve been repeatedly drinking the cocktail in a completely copper mug.
The Moscow Mule contains non-alcoholic ginger beer along with a shot of vodka and a very generous splash of lime juice.
“The problem with the copper mugs is that copper is a heavy metal and as such it can become toxic, if not fatal, over a period of time, so it’s not an immediate danger,” says David Werning of the Iowa Department of Inspections and Appeals. “If we find the use of copper mugs in an establishment we inspect, it’s cited as a violation of the food code and then the establishment is given time to correct it.”
The bar or restaurant has the option of taking any drink served in a copper mug off the menu — or getting new copper mugs, which have a nickel or stainless steel lining inside and a “food-safe” lacquer finish on the outside. Werning says he can’t recall an Iowa bar or restaurant being cited for the use of solid copper mugs.
Federal guidelines state the food or drinks with a pH balance below 6 are not to come into contact with copper — as that can cause food-borne illnesses.
“When the pH of the, in this case, beverage is lower than 6.0, the copper leaches into the beverage and then it’s consumed by the person,” Werning says, “and then, over time, it can become fatal.”
Werning says there’s a major reason why most if not all bars and restaurants in the state use the appropriate copper mugs with a lacquered exterior and a stainless steel or nickel lining. A solid copper mug is far more expensive.