Copper cups are safe to drink, and most Moscow mule cups are lined with another material that completely eliminates copper exposure and copper toxicity concerns. Even with unlined cups, copper poisoning is only possible when the body is exposed to large amounts of copper. As we explain below, guests are unlikely to be exposed to such a large amount of copper while drinking from a copper cup at a bar.

Is it safe to drink from an unlined copper cup?

Unlined copper cups are generally safe to drink, as there is little chance of copper poisoning. According to a study by the National Research Council, symptoms of copper poisoning appear only after ingesting 30 milligrams per liter of copper and placing it in an unlined pure copper cup for several hours.

This means guests would need to drink a litre of Moscow mules that have been sitting in unlined copper cups for hours before copper poisoning could occur.

Lined and unlined copper cups

For Moscow mule lovers, drinking from a pure unlined copper cup is unlikely to produce copper poisoning. Still, the potential cannot be ruled out. As a result, some bar owners may prefer to stock copper lined cups to facilitate maintenance, reduce health concerns, or comply with state regulations regarding the use of copper lined cups. You will find that many copper cups purchased are plated on stainless steel, nickel, or tin, or lined with these materials.

Copper cup safety

In July 2017, the Iowa Department of Alcoholic Beverages issued an advisory notice that raised safety concerns about copper cups. In this report, the department informed the public that, in line with the FDA's position, cocktails will no longer be served in unlined copper cups in Iowa.

Why does Iowa ban unlined copper cups?

Iowa banned the use of unlined copper cups following FDA recommendations. The FDA claims that copper may leach from unlined copper cups into foods and beverages with pH below 6. As a result, the FDA recommends that companies do not allow copper to come into contact with foods and beverages with this level of acidity. Moscow mules fall into this category, as both lime juice and ginger beer have pH levels below 6.

However, many states allow the use of unlined copper cups in bars. Be sure to check your state's regulations to find out which type of copper cup to use.

Unlined or lined copper cups are less likely to cause copper poisoning in bars. In order to fully ensure the safety of drinking, be sure to properly maintain your copper cup. If these cups are properly maintained, your guests can enjoy drinking from this quaint, special cup for years to come.