The Hidden Danger Behind Moscow Mule Copper Mugs

The iconic copper cup used to serve this drink has a dangerous secret.

Two copper mugs on black stone coasters filled with a liquid and topped with a lime wedge

Shutterstock / Joshua Resnick

Fans of trendy cocktails, hold onto your limes: The Moscow Mule has just been deemed this summer’s most dangerous drink. For once, it’s not because of the alcohol. It’s because of the mug.

What’s With the Mug?

A traditional Moscow Mule is served in a copper mug, which over time has become as associated with the beverage as the stemmed glass is with the martini or thin flute is with champagne. Quite simply, it’s just not a Moscow Mule if it’s not encased in metal; the presentation is just part of what had made the cocktail iconic.

However, the drinkware actually serves a nonaesthetic purpose as well. Copper instantly becomes chilled when it is met with a cool beverage, leading to an extra-cold sensation when you drink the liquid. This insulation, up to 400 times more effective in cooling and holding cold than a typical glass, means that your drink won’t get warm no matter how long your sweaty hand grips the side. Some people say the copper lends the drink a unique metallic taste as well, but this is purely subjective.

Why It’s Dangerous

Sometimes, though, the things that we love might be hurting us. (Like chicken… are you making these mistakes with the raw bird?)

Whatever these voguish vessels gain in fashion and function is lost in safety. The Iowa Alcoholic Beverages Division recently issued an advisory bulletin warning that the classic copper cups can give people food poisoning. They suggest that no drink with a pH level below 6.0 be served in copper. FYI: the components of a Moscow Mule have an average pH of 4! Drinks that acidic might begin to actually break down the metal alloys in the copper, which can let dangerous compounds seep into the liquid. The result? One mixed drink we don’t want to be sipping.

Our Solution

There is a silver lining, however, and we mean that literally. If your copper mugs are lined with a silver-colored metal such as nickel or stainless steel, you stand little risk of copper poisoning. Forgoing the warnings could lead to some pretty icky business like stomach pain, yellowing of the skin and worse-so to be safe, it’s best to drink your Moscow Mules exclusively from copper mugs with an inner lining. Or sacrifice the recognizable appearance and serve in a normal glass instead.

Pro tip: Mimic that extra-frosty temperature by keeping mugs and cups in the freezer before you serve.

Looking for more ways to chill your party beverages? Click here for a genius party hack.