Quantifying the Rate Copper Leaches From a Copper Drinking Vessel Into Simulated Beverages Under Conditions of Consumer Use

The Moscow Mule cocktail, which contains ginger beer, lime juice, and vodka, is commonly served in a copper mug. There has been increasing concern that copper can leach into the cocktail, given the acidic nature of the drink. Under the experimental conditions studied, copper does leach from the copper mug into the beverage. We observed copper leaching into the cocktail solution at a rate of 0.048 +/- 7 x 10(-4) ppm copper/min at room temperature. The leaching rate was found to be dependent on the acidity of the solution (increasing at lower pH) and molecular oxygen content. We quantified the copper concentration using inductively coupled plasmaatomic emission spectroscopy (ICP-AES). The rate of copper leaching into the Moscow Mule cocktail was found to be significant and accumulated copper concentration exceeds the U.S. Environmental Protection Agency standards for drinking water within 27 minutes (World Health Organization, 2004). Any risk posed by the accumulation of copper, however, can be mitigated by serving the Moscow Mule cocktail in a copper mug lined with stainless steel to avoid direct contact of the acidic liquid with the copper surface directly, as stipulated by the Food and Drug Administration model Food Code.