What is a moscow mule?

A moscow mule consists of vodka, ginger beer and fresh lime juice, in the ratio 45 ml, 120 ml and 10 ml, served over ice.

The official recipe of the International Bartenders Association lists those three measures. First fill the mug or glass well with ice, pour in the vodka and the ginger beer, add the lime juice and stir gently once so everything is mixed. A slice of lime goes on top.

The ratio comes down to about one part vodka to almost three parts ginger beer. If you keep to that ratio when filling a bigger mug, the strength of the drink stays the same.

The copper mug is tradition and not a requirement: the official recipe mentions a mule cup or a rocks glass, in both cases filled with ice.

Copper conducts heat well. A copper mug therefore quickly takes on the temperature of the ice, and you feel that on the outside of the mug. The rest of the story is recognisability: the mug belongs to the image of this drink.

There are rules for copper in contact with acidic drinks. The American model code for the hospitality industry, the FDA Food Code, does not allow copper and copper alloys such as brass in contact with a food with a pH below 6 (article 4-101.14). Mugs lined on the inside with nickel or stainless steel are not covered by that and are readily available. If you want to be sure, look at the inside of the mug.

Ginger beer is made by fermenting a mixture of ginger, water, sugar and yeast; ginger ale is a soft drink of carbonated water with ginger flavouring.

Because of that fermentation, ginger beer originally has a small alcohol percentage, because it is bottled before the fermentation is finished. The version sold as a soft drink is less sweet than ginger ale and has a more pronounced ginger flavour. If you want to know exactly whether it contains alcohol, read the label.

The official recipe prescribes ginger beer. With ginger ale you get a sweeter and milder drink, and that is not wrong, but it is a different drink from the moscow mule on the official list.

A Moscow Mule with 45 ml of 40 percent vodka ends up in the glass at about 10 percent alcohol, and that is about 1.4 standard glasses.

The calculation is included so that you can check it. 45 ml of vodka at 40 percent gives 45 times 0.40 is 18 ml of pure alcohol. The glass contains 45 plus 120 plus 10 is 175 ml of liquid. 18 divided by 175 is 0,103, so about 10 percent alcohol by volume, calculated without the meltwater from the ice.

Calculated in grams: 18 ml of alcohol weighs 18 times 0,789, which is 14.2 grams. A standard glass in the Netherlands contains about 10 grams of alcohol, so 14.2 divided by 10 is about 1.4 standard glasses. This sum assumes ginger beer without alcohol. If the can or bottle does state a percentage, that comes on top.

You make a moscow mule without alcohol with 120 ml ginger beer, 10 ml fresh lime juice and a mug full of ice.

In place of the vodka, you can pour 45 ml of an alcohol-free alternative to vodka.

If you leave out the vodka entirely, the mug is not full. Then top up those 45 ml with cold water or with extra ginger beer, so that the ratio between lime and ginger beer stays the same as in the original. An alcohol-free alternative to vodka fills that same place without the alcohol percentage.

Let daarbij op de ginger beer zelf. Gegiste ginger beer kan een klein percentage alcohol bevatten. Moet de drank helemaal alcoholvrij zijn, lees dan het etiket. NIX18: geen alcohol onder de 18 jaar.

A mule with dark rum is called a dark mule, a mule with gin is called a gin mule. The build with ginger beer and lime stays the same.

On the official cocktail list, the rum variant appears under the name Dark ‘n’ Stormy, with 60 ml of dark rum and 100 ml of ginger beer in a highball glass with ice, topped with a wedge or slice of lime. The rum goes on last, on top, so that it stays in a layer on the ginger beer.

The gin mule follows the structure of the moscow mule, with gin in place of the vodka. This variant is not on the official list, so there is no fixed ratio; the 45 ml, 120 ml and 10 ml of the moscow mule is a workable starting point.