The Science Behind Shaking, Stirring, And Muddling Cocktails

The alchemy of bartending can seem mysterious, with precise measurements, the flourish of a shaken mixture, a grinding of ingredients, or a swish of a wand-like bar spoon through a concoction. While the magical composition of cocktails is debatable, it's clear that exacting bar-top science is the key to a perfect drink. To help us dispel myths and uncover truths about why we shake, stir, or muddle our cocktails, Molly Horn, chief mixologist and spirits educator at Total Wine & More, is our expert advisor.

The age-old question, Shaken or stirred?, asks how you'd like your drink, but first it's useful to understand the why. Horn makes the answer simple, reminding us of the value of "that important cocktail ingredient: water!" Adding just the right amount of dilution to your drink balances its ingredients, makes it more approachable, and transforms a concocted glass of straight liquor into a refreshing cocktail. Along with the dilution that shaking and stirring both contribute, they also chill the drink.

How long you shake your cocktail may depend on the desired level of dilution, but using the right ice also has a profound impact. Horn highlights what can make or break the shake, suggesting using one or two-inch square ice cubes for improved texture and integration of flavors with the right amount of dilution. She says, "Imagine shaking [a] cocktail with chipped, crumbly ice for too long — instead of too strong across the board, it will taste bland, watery, and out of balance."

Horn also describes that in over-diluted drinks, sour flavors can become more prominent, overpowering the sweet element and upsetting the equilibrium. "The same thing happens if you fill your cocktail glass with ice before you build and shake your cocktail — that ice starts to melt in the glass while you work, and you're left in a similar predicament."

Counterintuitively, over-dilution can also result from using too little ice and failing to lower the temperature enough. Horn offers a key pointer on proper technique that makes a notable difference: "Fill your shaker or stirring glass ALL the way up with ice — the more ice, the less it will melt in the production of the cocktail but the better it will chill your beverage!"

Shaking a cocktail yields a colder drink than a stirred one, due to small flecks of ice that break off and melt in the drink. Speaking more scientifically, the shaken method chills a drink faster, with shaking achieving in seconds what stirring takes minutes to do. 

So what does stirring have over shaking? Well, dilution taking longer gives the bartender more control without the variable of chipping ice flakes. Shaking can also make cocktails like negronis or Manhattans cloudy. While stirred drinks lack the aerated texture that some shaken cocktails have, they can offer a smoother or silkier mouthfeel. If you need a drink to be warmer, boozier, or more intense, then stirring is likely the way to go.

Another key part of mixing many cocktails is muddling, which is the process of crushing ingredients in the shaker, mixing glass, or directly into the serving glass. How much thought can really go into pulverising herbs or fruit at the bottom of a glass, though? Well, as Horn describes, "Muddling in a cocktail is similarly nuanced in that there are a few different ways to do so depending on the ingredients being muddled."

"Starting with the most common, a sugar cube for an old fashioned, you want to really grind that sugar cube down. Adding the bitters directly to the cube before muddling makes it easier and helps to form a paste of sorts for the base of the cocktail."

Conversely, muddling more fragile ingredients, such as herbs like mint or basil requires a softer touch. "You have to be much more delicate and gentle, really only bruising the herbs — otherwise they can very quickly get bitter and throw off the balance of the cocktail. This also goes for muddling whole fruit wheels or wedges that still have the peel, as over-muddling those can also release too much of the bitterness in the pith."