Moscow mule

A Moscow mule is a cocktail made with vodka, ginger beer, and lime juice; garnished with a slice or wedge of lime, and a sprig of mint. The drink, being a type of buck, is sometimes called vodka buck. It is popularly served in a copper mug, which takes on the cold temperature of the liquid.
Some public health advisories recommend copper mugs with a protective coating (such as stainless steel) on the inside and the lip, to reduce the risk of copper toxicity.
Due to the popularity of the Moscow mule, other buck cocktails with different liquors or other ingredients have been labeled with the "mule" name in recent years. Variations with the name changed accordingly:
Another variation uses ginger syrup instead of ginger beer.
Other ingredients, such as carrot juice and angostura bitters, can also be added.
A variant which uses Mountain Dew soda in place of the ginger beer is known as a Moscow Mole.
George Sinclair's 2007 article on the origin of the drink quotes the New York Herald Tribune from 1948:
Mayo Methot's husband, Percy T. Morgan, an oil tycoon, was a co-owner of the Cock n' Bull restaurant.
This story was well known for years, however in 2007, a new version of the invention of the Moscow mule cocktail was published. In this story the cocktail's inventor was Wes Price, getting the idea from Hudes Potache, Morgan's head bartender and the drink was born out of a need to clear the bar's cellar, packed with unsold inventory, including vodka and ginger beer.
Eric Felten quotes Wes Price in an article that was published in 2007 in The Wall Street Journal
The Moscow mule is often served in a copper mug. The popularity of this drinking vessel is attributable to Martin, who went around the United States to sell Smirnoff vodka and popularize the Moscow mule. Martin asked bartenders to pose with a specialty copper mug and a bottle of Smirnoff vodka, and took Polaroid photographs of them. He took two photos, leaving one with the bartender for display. The other photo was put into a collection and used as proof to the next bar Martin visited of the popularity of the Moscow mule. The copper mug remains, to this day, a popular serving vessel for the Moscow mule.
According to a 1942 Insider Hollywood article, the Moscow mule was most popular in Los Angeles, where it originated. The Nevada State Journal (October 12, 1943) reinforced the mule's popularity in reporting: "Already the mule is climbing up into the exclusive handful of most-popular mixed drinks". It became known as a favorite drink of Reno casino owner William F. Harrah. In his book Beat the Dealer (1964), Edward O. Thorp did not name the Tahoe casino where he thought he had been poorly treated as a card counter. Instead, he wrote, "Immediately I had a Moscow mule", subtly hinting that the location was Harrah's Lake Tahoe, due to Harrah's then well-known proclivity for the drink.
Following the Russian invasion of Ukraine in February 2022, some American and Canadian bars began to refer to the drink as a "Kyiv mule" – referring to the Ukrainian capital of Kyiv – in protest of the invasion.
There are some health concerns related to the tradition of serving a Moscow Mule in a copper vessel. The ingredients in a Moscow mule cocktail are acidic, and the resulting beverage has a pH well below 6.0. This creates a problem when using traditional copper mugs without coating, as copper can start dissolving into acidic solutions. Copper in solution is considered toxic at concentrations above 1 mg/L. On July 28, 2017, the Iowa Alcoholic Beverages Division issued a statement that pure copper vessels should not be used to serve acidic drinks, but that "copper mugs lined on the interior with another metal, such as nickel or stainless steel, are allowed to be used and are widely available". The U.S. Food and Drug Administration (FDA) 2013 Food Code states that 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 or for a fitting or tubing installed between a backflow prevention device and a carbonator."
The FDA's Model Food Code specifically prohibits copper from "coming into direct contact with foods that have a pH below 6.0". The advisory relates only to solid copper mugs. Copper mugs that are lined with stainless steel or other food-safe materials are exempt from the advisory.
The risk of copper poisoning has however been questioned by Trisha Andrew, who teaches chemistry at University of Massachusetts Amherst, saying that the cold temperature and the short duration of a usual serving would not cause the copper levels to rise high enough to pose a risk.