According to an advisory bulletin from the Iowa Alcoholic Beverages Division, the popular cocktail known as the Moscow Mule could be a public health threat.
This drink is commonly offered in copper mugs, and therein lies the potential problem. The FDA’s Model Food Code states that foods with a pH under 6 may not be in contact with copper and its alloys, because this toxic metal can make its way into the solution at higher acidity.
Copper is relatively insoluble in water, but acidic conditions can make it easier for extremely small amounts to dissociate, presenting a risk of exposure to abnormally high concentrations.
According to Hordyjewska et al., in their 2014 Biometals paper entitled “The many ‘faces’ of copper in medicine and treatment,” copper toxicity can involve gastrointestinal upset, abnormally fast heart rate, and breathing problems, along with some other unpleasant symptoms. These are found with acute exposure to concentrations of 3 mg/L and greater. If this number sounds high, that’s because it is. While this number concerns acute exposure, and not long-term exposure (like what may be happening in habitual Moscow Mule drinkers), it represents a surprisingly high minimum concentration for toxicity.
This certainly causes one to question whether the FDA rule can be used as an indicator of potential danger. However, copper toxicity is clearly not something to mess around with. So, while those copper mugs cry out for an annoying Instagram post, they should also give us at least a little pause. Here’s a recipe, in case you want to dance with the devil. Include copper at your own risk.
• 1-1.5 oz vodka
• 4-6 oz ginger beer
• Juice of a lime
Combine ingredients and drink over plenty of ice, with a lime wedge to garnish.
By Scott Bittner