Moscow Mules—vodka, ginger beer and lime juice served ice cold—are one of the trendiest drinks at bars and restaurants across the country right now. And the signature copper mugs they’re served in have made a name for themselves too—we saw them on pretty much every holiday gift guide last year. But, it turns out those copper mugs might actually be dangerous. Here’s why.
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A recent advisory bulletin issued by The Iowa Alcoholic Beverages Division explains the state’s adoption of the FDA’s Food Code, which says “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.”
This poses a problem because the pH level of a typical Moscow Mule doesn’t even come close to a 6 when you consider its main ingredients, ginger beer and vodka, which are both acidic with a pH level of 4, and lime juice, which is even more acidic with a pH of 2. The potential danger occurs when these types of ingredients come in contact with the copper lining of the mug, as it can seep into the drink itself, resulting in food poisoning.
However, there’s a silver lining: According to The Iowa Alcoholic Beverages Division, copper mugs that are lined with another metal such as nickel or stainless steel, are “widely available,” exempt from this health concern and “legal” to serve (at least in Iowa). So if you own these trendy copper mugs already or you’re in the market for some, check with the manufacturer or read the fine print before you buy.
