A muddler is a bartender

Bartender

A bartender is a person who serves beverages behind a counter in a bar, pub, tavern, or similar establishment. A bartender, in short, "tends the bar". The term barkeeper may carry a connotation of being the bar's owner...

's tool, used like a pestle to mash — or muddle — fruits, herbs, and/or spices in the bottom of a glass to release their flavor.

Popular cocktails that require the use of a muddler include the Old-Fashioned

Old-fashioned

Old-fashioned may refer to:* Old Fashioned, a cocktail* Old fashioned glass, a type of drinking glass* Old-fashioned three, a basketball term* "Old-fashioned" a 1976 short story by Isaac Asimov* Old Fashioned, a racing horse...

 made with whiskey, the mojito

Mojito

Mojito is a traditional Cuban highball.Traditionally, a Mojito is not very strong and made of five ingredients: white rum, sugar , lime juice, sparkling water and mint. The original Cuban recipe uses spearmint or yerba buena, a mint variety very popular on the island...

 made with light rum

Light rum

Light rum , is a dry, light-bodied rum, light in color and lightly sweet in flavor. It is produced from sugarcane juice and molasses, and normally has a short aging period....

, the caipirinha

Caipirinha

Caipirinha is Brazil's national cocktail, made with cachaça , sugar and lime. Cachaça is Brazil's most common distilled alcoholic beverage . Both rum and cachaça are made from sugarcane-derived products...

 made with cachaça

Cachaça

Cachaça is a liquor made from fermented sugarcane.It is the most popular distilled alcoholic beverage in Brazil. It is also known as aguardente, pinga, caninha and many other names...

 (as well as the caipiroska

Caipiroska

Caipiroska is a form of Caipirinha prepared with vodka instead of the usual cachaça. It is a popular cocktail in Brazil and in Uruguay. It is also sometimes known as Caipivodka...

 made with vodka

Vodka

Vodka , is a distilled beverage. It is composed primarily of water and ethanol with traces of impurities and flavorings. Vodka is made by the distillation of fermented substances such as grains, potatoes, or sometimes fruits....

 instead of cachaça

Cachaça

Cachaça is a liquor made from fermented sugarcane.It is the most popular distilled alcoholic beverage in Brazil. It is also known as aguardente, pinga, caninha and many other names...

) and the mint julep

Mint Julep

The mint julep is a mixed alcoholic drink, or cocktail, associated with the cuisine of the Southern United States.- Preparation :A mint julep is traditionally made with four ingredients: mint leaf, bourbon, sugar, and water. Traditionally, spearmint is the mint of choiceused in Southern states, and...

 made with Bourbon whiskey

Bourbon whiskey

Bourbon is a type of American whiskey – a barrel-aged distilled spirit made primarily from corn. The name of the spirit derives from its historical association with an area known as Old Bourbon, around what is now Bourbon County, Kentucky . It has been produced since the 18th century...

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