US state issues warning over copper cocktail mugs

A US state department has issued a formal warning over the use of unlined copper cocktail mugs, claiming that they could poison imbibers.

moscow mule cocktail in copper cup with mint and lime garnish

Copper mugs have gained in popularity in recent years as a trendy cocktail receptacle, and are particulalry common when serving a Moscow Mule.

However Iowa’s state Alcoholic Beverages Division has issued an advisory bulletin reminding bartenders of the danger in using unlined copper mugs, warning of the poisonous nature of copper and copper alloys when mixed with acidic foods.

The state’s Food and Drug Administration’s Moral Food Code prohibits copper from coming in direct contact with foods that have a PH below 6.0. Such liquids include vinegar, fruit juice and wine, as well as lime juice, a key ingredient in many cocktails, including the Moscow Mule.

High concentrations of copper are poisonous and can cause foodborne illness, it said, as copper can leach into foods when it comes into contact with acidic foods. Copper toxicity, sometimes referred to as hypercupremia or copperiedus, can also occur from eating acidic foods that have been cooked in uncoated copper cookware.

According to the NHS, symptoms of copper poisoning include vomiting, stomach pains, confusion, drowsiness and fainting fits. Thankfully, mugs lined with stainless steel or nickel are deemed safe.

“The PH of a traditional Moscow Mule is well below 6.0,” the warning states. “This means that copper mugs that have a copper interior may not be used with this beverage.

“However, copper mugs lined on the interior with another metal, such as nickel or stainless steel, are allowed to be used and are widely available.”