Moscow Mules, good for happy hour and even better for likes on Instagram, have enjoyed a renaissance as of late. And as with all enjoyable things, discovering the serious health risks they carry is right on schedule. This time, it’s the copper mugs the cocktails are served in.
The state of Iowa recently released a bulletin regulating the use of copper mugs by food and beverage sellers. The Food and Drug Administration’s Food Code, which Iowa has adopted, prohibits foods with a pH below 6.0 to come into contact with copper. A Moscow Mule, with its acidic ginger and even more acidic lime juice, has a pH “well below” 6.0.
In a traditional mug, that acidity breaks down the metal and causes copper to leak into the drink. This isn’t great; copper poisoning can cause diarrhea, vomiting, abdominal pain, and yellow skin. “Sudden (acute) copper poisoning is rare,” says the National Institute of Health. “However, serious health problems from long-term exposure to copper can occur. Severe poisoning can cause liver failure and death.”
So no, a Moscow Mule probably won’t kill you, unless your bartender has a seriously heavy hand. But there’s enough of a risk for Iowa to ban the copper mugs, unless they’re coated on the inside with a different material, like nickel or stainless. It’s safer, and still pretty enough for a photo op. If screening copper mugs for proper insulation is too much of a pain in the ass, use a glass. The drink will still taste good—spicy and refreshing.